Construction and Waterproof Design

PROCESS

Once the contracts are awarded, questions are asked by successful bidders, usually during construction. Depending on the project particulars, the process can take on many paths from this point. Based on recommendations of the American Institute of Architects (AIA), requests for information (RFIs) are but one of many documents for processing changes to the contract documents. RFIs are most often initiated by contractor or subcontractors needing more information.

They can also be asked by the owner's team, or offered by design team members, depending on the client, contractor, and project dynamics (schedule). Other documents that one might use would include architect's supplemental instructions (ASIs), requests for proposal (RFPs), directives, and change orders (COs).

Over the years, these basic documents have been expanded.

ASIs were intended to be clarifications to scope previously shown in the documents and initially (at least in theory) had zero cost and time implications. They simply were to be clarifications. For example, the ASI could instruct the con tractor as to which color paint to use where or to supply a dimension to assist in layout. RFPs initially were supplemental drawings issued by the design team for the contractor to price. These often were for added scope but could be as simple as evaluating optional carpet pricing for glue-down carpet squares in lieu of roll goods. After the owners received the proposed price for the change, they could make a decision as to whether or not to proceed with the change.

There are at least three variations of directives. If something comes up during the course of construction that requires immediate action, a directive may be issued.

We have seen the architect, contractor, and owner all use directives in one project.

The architect might issue an architect's field directive (AFD) such as the addition of water stops in a concrete pour that may be underway. A contractor may issue a directive to proceed with work that was not shown rather than hold up the progress of the job. An owner may direct a contractor or construction manager (CM) to proceed on a cost-plus basis, on a not-to-exceed basis, or even on a pricing directive.

Only one client in all our experience used directives like his or her favorite credit card or checkbook. When a contractor received a directive, he or she felt confident they would be receiving additional payment for the work. This was on a resort project where time was money. As it relates to the envelope, a directive might be a good way to add a detail or get an additional membrane put on the wall before the next materials goes on.

PRE-CONSTRUCTION

Preconstruction meetings can be very beneficial to all parties. It’s an opportunity for the designers, owners, and contractors to discuss upcoming issues with the subcontractors. It’s a good time to express how important the building envelope is to the success of the project and to begin to get buy-in for the hierarchy (relative importance) list developed earlier. As the meeting relates to the site, site sections, water tables, soils, drainage, bearing capacities, and the upcoming season can be discussed. If it’s going to be raining during piping and foundation excavation, this is a good time to make plans of action. Most important, it may be the first time the subcontractors meet the project manager for the owner or the design team. Familiarity can lead to open communication throughout the next year or two.

Continuing with the preconstruction meeting theme, roofing, waterproofing, and wall installation subcontractors also should be present at the meeting.

Great success can result from spreading out the plans on the meeting table and going through the details one by one. Perhaps the subcontractors will have a good idea as to how to improve a flashing detail, or you can talk about substitutions for materials that may not be readily available owing to global pressures or new materials on the market that might work better than what is shown in the plans. This should not be seen as a chance to substitute lesser cost solutions for what was required by the contract documents. This is also a good time to discuss those seldom read documents-the specifications. Of particular interest, you should review warranty, mockup, shop drawing, and testing requirements. Try to build camaraderie through your mood and actions.

SUBMITTALS

Properly processed submittals modify the contract documents. They usually provide more accurate and detailed information than the design documents.

The initiator is usually a subcontractor who specializes in this scope, perhaps an installation-only subcontractor or perhaps a material supplier. Designers and construction engineers need to take their time reviewing shop drawings and every other form of submittal for compliance with contract documents and for coordination with every submittal that has come before. Of particular importance to me are submittals that define points of interface between systems.

Dimensions are only the first thing to verify. Check the thicknesses of materials and their composition, and read manufacturers' recommendations. We recently learned of delaminating metal-clad wood windows used in an ocean front home in West Palm Beach, wherein the manufacturer specifically stated that these windows should not be used on or near the coast.

Most window and door submittals stop at the edge of the product being pro vided. This can disguise important flashing, membrane, fastener, and sealant considerations that will affect the envelope's performance against the elements.

Check to ensure that the particular extrusion shapes provided work with the intended geometry of the sections. All these steps should be undertaken first in the general contractor (GC) or construction manager (CM) office by their field engineer or person of similar responsibility before forwarding them to the designer for review. In the ideal world, all specification requirements are met by the product being submitted. If something needs special attention, the con tractor should put a green cloud around it, and note it for the architect or engineer to look at with their marks then made in red. The same process just described should be performed by the design team after receipt. If either the GC or designer is too busy, too lazy, or perhaps unaware of the importance of full review of submittals, problems that could have been avoided will have a higher probability of happening.

SCHEDULING

Most construction contracts contain language requiring detailed schedules for activities shortly after award of the contract. These schedules are comprehensive task lists with sequencing and durations for all major components of the building. Such schedules frequently list submittal dates and allow reviewers time for the process of approval. Three important activities as they relate to the building envelope are the roof and wall systems, windows skylights and mock ups. The initial schedule will serve as a planning tool for sequencing all construction activities for the duration of the job. It’s usually updated constantly as things change in the dynamics of a construction project in the real world.

The reason we list roof, wall, and mockups is that we want to make certain that these submittals come in sufficiently early to permit adequate time for review, as well as time for revised, returned submittals. The issue of mockups gets over looked all too often or delayed until they are less useful. We urge everyone to have mockups built early in the schedule. These often solve details for the most complex conditions on the envelope and let everyone know the sequence of trades required to build these details. Often, in the rush to get buildings done on time, trades can get shuffled around, submittals get sent in late, and (as an example) the stucco crew can get ahead of the flashing or roofing counter flashing crews. These out-of-sequence installations can help the schedule but can lead to pathways for water intrusion and compromise the performance of the building envelope.

Well-crafted schedules link activities that need to follow each other to prevent such out-of-sequence installations from happening. The initial schedule should also show critical path activities, calling attention to key tasks that must be completed by a specific time if the target completion date is to be met. One more important aspect of the schedule is float (or fluff). Float is time in excess of what may be required, extra time if you will, so that if something takes longer than anticipated, it does not affect the next task in sequence. An achievable schedule will have float in many areas when it’s first developed. A good team will man age float, even adding to the float whenever possible early in the job.

Finally, with regard to the schedule, make certain that sufficient time is allowed for dry-in to be achieved prior to starting inside finishes. Look to see the relationship between the start of roofing activities, wall sheathing, glazing, and door installations as it relates to stocking the job with interior sheathing, insulation, etc. Make certain that there is float in the roofing schedule to permit installation to slip a few rain days (or weeks) without causing delays. See where heating, ventilation, and air-conditioning (HVAC) equipment startup is relative to finishing drywall, installing any wood products, etc. Then look at substantial completion and the preceding activities. Make certain that there is adequate time for punch-list inspections and corrective work. The worst schedules can lead to installations out of sequence, installing roofing when the lightweight concrete is still wet and paint or sealant application before substrates are sufficiently dry, clean, or cured, etc. Don't let the schedule cause future problems.

If a conflict arises, get the construction team together with the design team to figure out a way to work around the situation. There are ways to overcome most challenges; they just may not be obvious at first glance, easy, or free.

As an example, we would like to share with you a detail that was developed for a project where the roofing contractor was 2 months behind schedule. The metal stud and drywall crews were ready to install sheathing and begin stucco activities.

Unfortunately, all flashings were in the roofer's contract. The detail as designed required the flat-seam metal roofing installation to be complete before stucco could begin --. The CM needed the stucco subcontractor to start immediately. As the on-site architect's representative, we were able to develop a revised detail -- that revised the design to enable stucco work to begin in advance of roofing. The simple work-around enabled work to proceed without compromising the performance of the envelope. Don’t allow the schedule to be an excuse for creating future problems.

Roof-to-wall detail, as designed. Wall Framing Wall Sheathing Vapor Barrier Vertical Leg of Flat Seam Roofing Stucco with Weep Screed Flashing Metal Roofing; Roofing Membrane Roof Sheathing Roof Framing; Roof-to-wall detail, as built. Wall Framing Wall Sheathing Vapor Barrier Counter-Flashing Stucco with Weep Screed Sealant in Flashing Metal Roofing; Roofing Membrane Roof Sheathing Roof Framing

LONG-LEAD ITEMS

As soon as the contract is awarded, scheduled tasks should include purchase of long-lead items. For those unfamiliar with the term, it applies to items that require a long time between initial intent to purchase and delivery of completed items. This frequently may include fabricated steel parts such as bar joists and custom structural members or curtain wall systems. The reason these are important to recognize is their potential impact on closing in the building.

Successful projects manage to coordinate installations of roof and wall components so as not to affect the proper sequence and duration of trades. Failure to acquire long-lead items on schedule can lead to an interruption to the optimal rate of application, curing times, hydration, or other deviations to the trades that follow.

EARLY-BID PACKAGES

There are several ways that construction schedules can be shortened. One way is to put more people on each installation crew. Another is to work three shifts.

While there may be projects where this is the only way to achieve the owner's objectives, it’s certainly not the normal way buildings are built. It’s not unusual for projects to work 10-hour days or 6 and 7 days a week, but this is usually reserved for a short burst and not for several months. One method for delivering buildings earlier is to get an earlier start. Since we can't usually get under contract sooner or speed up the permit review process, we have to look elsewhere. One other place to look is in shortening the design process, but designing a custom building takes time, and the process is iterative. It’s completed in stages, with solutions being developed through a process of calculation, analysis, and synthesis. It often requires an accumulation of information from outside sources such as surveyors, soils-testing labs, and other people.

All these take time. Often, it takes longer to get questions answered by the client group than it does to design the building.

Rather than take a chance on shortening the process of architecture, structure, mechanical, electrical, furniture, landscape, acoustics, and all other design disciplines, it has become common to break out early-bid and construction packages. This can work in concert with long-lead items, as touched on earlier. On one of our current projects, we were able to submit an early foundation package and get it fabricated and the foundations built while the building permit was being completed and accepted. The result was a 4-month reduction in total project duration. When inflation rates approach 10 percent per year and you are able to purchase materials soon after contract award, the time saved could lead to more than 4 percent savings in project cost. A lot of material, such as concrete, steel, piping, mechanical and electrical systems, gear, and fixtures, can be bought sooner as a result of good planning and an early-bid package.

One thing that I've learned is that the sooner you get the building finished, the sooner the owner quits making changes. Changes can kill a project's momentum and lead to lower cost-effectiveness and less profitability for all involved.

STORAGE and PROTECTION

Manufacturing companies such as General Motors are expert in ordering materials from suppliers and stipulating delivery just in time for installation.

Builders have moved in the same direction but have not achieved the same control over their suppliers. Often we will accept a delivery more than 6 months before we need something. There are several reasons why this can occur, and if it’s part of the purchasing plan, then provisions must be made to protect early-delivered materials. Some suppliers can store materials until needed, whereas others must deliver them to make room in their yards. Some purchasers store materials in air-conditioned storage areas. This protects them from the elements and theft.

The worst thing that can happen to stored materials is exposure to water.

Materials stored on site need to be well covered and stored in an area that won’t flood or even be wetted by wind or rain. The other important consideration is preventing wind-borne mold spores from settling on the materials. Both water and mold spores must be prevented from contact with materials, especially porous materials with organic content such as wood and paper products.

Most construction specifications will address protecting materials and work in progress. Exterior walls constructed out of concrete masonry units (CMUs) or brick should be covered with a waterproof membrane after each day's work or before rain events during working hours. These coverings should be maintained in a manner as to not be displaced by wind or by other trades. Failure to do so may lead to water getting in the wall where it’s not supposed to be.

This can lead to mold growth that may go unnoticed for months or years until a trigger event in the future leads to occupant complaints and potential remedial work. Once spores begin to spread their tendrils, the best means for correction is removing the materials. Another problem caused by masonry exterior walls getting wet is excessive efflorescence. This is the result of moisture causing reactions with lime, calcium or other chemicals in the wall. Efflorescence is very difficult to stop once it begins. If possible, protect masonry, brick, stone, and block until the exterior finish is applied, whether it’s paint, stucco, or a clear protective coating such as silane. Install roofing, flashings, gutters, and drains as soon as proper sequencing will allow.

Interior materials are even more important to protect against water and mold spores prior to installation, especially organic and hygroscopic materials that may contain paper or wood. Any material that gets installed inside the vapor barrier has a greater potential to affect future occupants than those outside the membrane. Paper-backed gypsum wall board, typically referred to as drywall, is the first interior finish material to be installed in many projects. Depending on the type of exterior wall system and the number of floors and wings, drywall installation may begin before the building is totally dried in and the air conditioning system is on. As soon as the subcontractor hangs the first interior walls near an exterior wall, get your umbrella out because it’s going to rain. With 3 inches of rain on the floor in areas, drywall will be getting wet. We recommend against installing any interior products that contain paper or wood until the envelope is complete or temporary closure is in place. Ideally, the temperature and humidity should be less than 90ºF and 50 percent, respectively.

Often electrical equipment rooms need to be constructed before the envelope is dried in so that temporary power can be distributed. One way is to construct them out of metal studs and fiber-reinforced gypsum products that are made without paper. This permits panels to be set, doors and hardware to be installed, and wires to be connected with an acceptable level of safety and control.

COORDINATING THE TRADES

Depending on the project team, coordination can be easy or nearly impossible. The best general superintendents make it possible for all trades to work together in noise and harmony. There is no such thing on a job site (at least not in our experience) as total peace and harmony. There is always grumbling. You can't make everybody happy all the time. But a good superintendent has the ability to get cooperation. A good superintendent will have planned the job and managed the schedule so that subcontractors can get in and get done with the least interference or interruption by others. More important than harmony is cooperation, and it starts with attitude. Hiring a good bunch of subcontractors and giving them enough time and money is a great starting point. Giving them space to do their work and get ting those before them to finish is the real trick. Due to the complexity of many building envelopes, you may have more than 12 subcontractors whose efforts have to be managed for one detail to work. A simple wall section may require the organization of 15 different trades. If one of them, e.g., the metal framing sub contractor, installs his or her work wrong or doesn't finish, it affects everyone who follows. Project schedules are usually updated weekly as a result of status checks and available work force. A material shortage can throw trades out of sequence if corrections are not made in the schedule as the problems are made known.

One of the beauties of a big project is that there are usually other areas of the project where a group of workers can be assigned in response to change in another area. This keeps the overall building schedule on track. Work that must be done off scaffolding creates its own challenges. The subcontractor paying rental for the scaffolding may not wish to leave it up in one section after his or her scope is done, and it’s uncommon to have two different trades working off the same scaffolding at the same time unless it’s provided by the GC or CM. When it comes to constructing multiple wythe walls and/or complicated details requiring close coordination between framers, sheathing installers, flashings, and finish material installers, it’s a good idea to limit the number of subcontractors. Try to award the flashing to the subcontractor installing the sheathing, membrane, and finish material. You may find that subcontractors often coordinate better among themselves because they work for the same boss than if the roofer is to install the flashings and another subcontractor has the membrane in his or her contract. Coordination of trades can begin with a careful award of subcontractor bids.

This is another benefit from building a mockup before work starts on the building. The subcontractors will learn who needs to go first, who goes next, and how best to work out the interface before they get up on scaffolding --. Let the subcontractors work it out on the ground before anybody has expended much material and labor on the project. This can lead to a better understanding of the intent of the drawings and give everyone involved more time to look at alternatives or to review the mockups and explain their expectations for quality workmanship.

--- Resolve details before you get on the scaffolding.

--- Outside corner void in slab.

ATTENTION TO DETAIL

It doesn't take much of an opening or a void in the exterior wall system to allow air and water intrusion. The old attitude of doing your job as fast as you can and letting the next guy worry about fixing problems you cause cannot be tolerated. Such a mentality can be pervasive and end up carrying through from beginning to end. A good project starts out right. Beginning with the design team, attention to detail often separates good envelopes from problem projects.

When that attention is carried through the construction personnel as well, it will result in better fit of parts, better scheduling for delivery of materials that work, and less air and water intrusion.

Each successive trade needs to be on the same page, starting with utilities and site work. If the utilities go in wrong, say, the storm drainage piping is run too flat, it can lead to roof drain failure or burst piping and fittings in walls. If the finish grades are not correct, surface water can be carried up to the exterior walls. The slabs must be cast properly, laid out right, and placed properly. When the foundation or floor gets installed with a problem, this can trickle through all the following subcontractors' work. Corrections should be made as soon as possible --. This outside corner condition for a resort was left uncorrected despite being reported to the general superintendent. We were told for weeks that the subcontractor would get around to fixing it. On the following Monday morning, the framing crews had already framed up the exterior wall, and exterior sheathing was installed before 8:00 A.M. The contractor allowed the condition to remain untreated long enough for it to become too much trouble to correct it. The resulting void was large enough to put a golf ball in. It was on the punch list at project closeout and received some cementitious patch material from the outside, after paint was on and landscaping was in. Slab-edge dimensions and form-stability issues can be the most problematic in closing off the floor to foundation and wall-sill condition. No project ever goes without some problems, but successful projects deal with these challenges as they come up-- preventing them from becoming problematic.

Attention to detail is more of an overall theme than it’s a practice applied to any one issue. It means paying careful attention to the general conditions and specifications. Don’t just scan the table of contents and decide to read only the portions on payment applications and start date. While some general conditions may be standard, off-the-shelf "boiler plate" specifications, you may find some of them useful in understanding what is important to the client. The sections on verification of existing conditions may be important in remodeling, as might sections on responsibility for code research and compliance. For building warranties and testing criteria, you need to look at the front end as well as the particular division you are bidding. Specifications often list acceptable manufacturers, materials, fasteners, and requirements for testing and approval agencies such as Underwriter's Laboratories (UL), American Standards for Testing and Materials (ASTM), etc.

As they relate to air and vapor membranes, specifications often list thicknesses, perm ratings (dry cup and wet cup), tack ratings, facings, reinforcing, contents, volatile organic compound (VOC) limits, application techniques, and more. Pay attention to the specifications; ask questions if you don't understand something.

Do your own research. Ask people you trust, even sales representatives or your peers. Sometimes it helps just to hear yourself talk about something. It doesn't happen often, but specifiers can make mistakes too. Review the plan and section details with a keen interest toward where the vapor barrier is in the wall system and roof sequence. Look to see how this fits with your planned sequence of installation. Look at flashings, windows, doors, and louvers and compare the details with what you have built in the past in the same climate and building type. Pay attention to compatibility issues. These can occur in metals, particularly where two different metals come in contact with one another. Metals with different valences (this has to do with their available electrons for chemical reactions) will react with one another. You should isolate dissimilar metals, such as steel, lead, copper, iron, and aluminum. Stainless steel doesn't react (much) when it comes in contact with any of these, so it’s commonly specified for use- especially where exposed to weather or view.

Paying attention also applies to observing construction in progress. Look at what is going up as to how it may affect your scope. If something just doesn't look right, there is a chance it isn't right. It’s amazing how when you walk the job site on a daily basis you will observe some activity that attracts your attention. On closer examination, you may learn something that is done well or see something that is not. Of special interest are voids in materials, large gaps between systems, penetrations that were not planned, and finishes going on before preparation is complete. Some of these items can be loose-fitting or unsecured components, dirty substrates, lack of or wrong fasteners, or worse- things that were left out.

Blocking and nailers can be a lot of work to install properly before sheathing begins. It takes a special kind of trained eye to look at framing and determine the places where sheathing needs end nailing or coping needs screws. If left out, these pieces can result in materials coming loose in heavy winds, and this allows rain in the envelope and water damage or flooding. After Hurricane Charley, we could see which builders had installed nailers and fasteners in corner conditions just by seeing what came loose and what stayed in place. This was especially evident in shingle roofing and vinyl siding.

We have observed roofing going on before surrounding work was framed in and wall finishes being applied before roof flashings were installed. We have seen installers try to hide rips in membranes by covering them up before too many people arrive at the job site in the morning. By carefully observing the details and specifications, and by watching it all go together, most future problems can be avoided-by fixing them before they can become problems.

--- Out-of-square drip edge.

--- Check for square using diagonal measures.

DIMENSIONAL TOLERANCES

We touched on this previously but feel that it’s important enough to make into a separate topic. With computers doing a lot of our dimensioning in design, we can get dimensions on plans down to the thousandths of an inch-but it doesn't help us very often. Construction dimensions seldom should be listed in increments smaller than 1/8 inch. Unless a part or component is being fabricated by a computer, about all humans can lay out consistently is eighths. There needs to be some room for the width of a line or sawblade to permit a construction worker the opportunity to make hundreds of cuts each day and the building still fit together adequately.

Designers should never dimension walls, floors, beams, columns, decking, or any thing else construction workers are to fabricate and install to 1/64”. You should plan for some flexibility. This is especially useful when different materials are being joined, such as windows being installed in concrete block and stucco walls.

Concrete blocks aren't always the same size, the joints vary in width, and the jamb may not be perfectly plumb, but in the end, they have to work together. Skilled and experienced carpenters can plan their cuts so that when wall sheathings and vapor barriers are installed, there is a consistent 1/2-inch gap between the prepared rough opening and the aluminum or wood window, but when they come back in the morning, the wood may have moved or warped. We must construct buildings so that they have room to move without causing leaks.

Design dimensions are important to maintain within acceptable deviations.

Overall out-to-out dimensions are usually adhered to closely, but the angle of wall intersections is harder to check. In tilt and precast concrete construction, there are many opportunities for layout errors to be made that may result in future difficulties. Every panel point and window or door opening gets formed and poured long before it’s used and sometimes before the floors are built. Prior to concrete placement, the forms should be checked and rechecked for conformance with intended dimensions and for "square." The length of one diagonal should equal the other diagonal measurement --. If not, the angles or side lengths are off, which could result in panels going up out of plumb or level.

Resulting voids between panels could vary in width, making it difficult to seal them properly, and this can be noticeably offensive --. Once dimensions are not followed or things get out of plumb or level, it can become difficult to make subsequent materials fit and seal properly.

More problematic than a void that may be too big is one that gets too small.

When window openings are completed, membranes and sill pans are installed, and the windows don't fit, this is another challenge. The cause is not as important as the cure. Maybe the wrong style windows arrived, or maybe the dimensions weren't checked closely in shop drawing review. Perhaps the rough openings did not account for the thickness of the sill pans and two layers of self-adhesive membrane (SAM) and folded air infiltration barrier (AIB). This is what we have tried to prevent and where things can go bad. This is where the right corrective decision is critical. It gets back to time and money. The project may have been waiting for these windows for months and needs them installed to get the next draw from the bank. Maybe the brick or stone is already on the building.

What happens next? Cram them in place and caulk over the gaps real fast so that nobody sees it? Cut off the fins so that the windows aren't so wide? Cut back the jamb returns a half inch on each side? After all, who will notice? Any of these three proposed solutions can result in potential leaks at the windows. Forcing the window into an undersized opening can lead to bending of the jambs or sills. This can result in bound operation or warps, and it would not leave room for expansion and contraction. Don’t ever caulk over a movement joint-that job is for sealants, and without proper joint geometry and bond breaker, sealant joint performance will be compromised. A project that is designed and specified for fin-type windows should not have non-fin windows installed without redesigning the opening protectives. This can lead to massive water intrusion and lawsuits the builder probably will lose. If the jambs are cut back, there is a good chance that the membrane may be exposed or cut. There are two obvious options that come to mind; however, avoiding this situation is the best solution. Having the windows premeasured and built to fit the openings before they are delivered would have prevented this from happening. Of the two options available, modifying the windows is probably the least problematic solution if the waterproofing is complete and the finishes are on. Have the installer measure the openings and take the windows apart, re-cut them, and re-glaze them prior to returning them to the job site. This may prove prohibitive in terms of both cost and schedule. The other option is to back up and remove the finishes, peel back the membranes, and correct the openings.

We recommend that similar types of actions be taken when the envelope gets penetrated by louvers, conduit, or pipe after the finish is installed. We offer the example of the 4-inch pipe the plumber has to install after the exterior wall has been complete and painted --. In this illustration, we had the stucco carefully removed for an area about 12 inches past the pipe penetration in all dissections. Wire lath was cut, screws were removed, and the lath was peeled back. The hole then was cut through the exterior sheathing, oversized by about ½”--.

--- Detail for vent pipe penetration of wall. Insulation Glass-Mat Sheathing AIB SAM Strip SAM Strip Fiber Cement Siding Fiber Cement Siding Plywood Blocking AIB Flashing Fiber Cement Plinth Block Sealant Vent Pipe Manufactured Gravity Type Vent

A new square of SAM was installed, primed to the sheathing, and behind the original SAM by a few inches. The new SAM was primed and sealed to the old SAM.

A new piece of envelope AIB was cut and installed on top of the SAM. We then had the AIB (in this case Tyvek Commercial wrap) sealed to the pipe with Tyvek tape after cleaning the pipe and taped to the surrounding AIB. This was stucco exterior finish, with cement board trim, so we installed an 8 inch square of cement board to trim the penetration. We then had j-bead installed around the edges, leaving a small void for sealant --0). The lath around the hole was repositioned and wired to strengthen the cut mesh, and new three coat stucco was applied. This is the least common path of correction but would result in the responsible parties learning from their mistake. Sealing patched air and vapor barriers is not difficult.

--- A clearly marked RFI with circles and arrows.

ASKING the RIGHT QUESTIONS

With so many advances being made in chemistry and material sciences, new products are being introduced to building industry each year. No one person or firm could possibly know everything about any of them. With information so readily available on the Internet, it has become the first source of information for many designers and builders alike. There are articles on products, means, and methods for most products, but you have to be a little careful. Much of what you may read can contain biased information, such as from a manufacturer's sales representative. Sales representatives tend to recommend their own products and list problems with their competitor's. Manufacturers' data sheets, catalogs of products, and manufacturers' recommendations for use generally are the most reliable sources of technical data. Check the permeability ratings for yourself. Look at Material Safety and Data Sheets (MSDSs) to see recommendations for worker's safety, off-gassing information, and possible solvents used. See how long the materials can be exposed to ultraviolet (UV) radiation before voiding the warranty. Find out how long the materials take to cure and how soon after application they can be covered up. Call the factory technical department and talk to them about your location and planned use. Ask the tech people for tips and tricks.

Another excellent source of good information is the installing subcontractor.

This source should be familiar with materials used in the region and may have first-hand knowledge about success stories or failures associated with the system. Of course, installers can be the most biased, and their information should not be the only data used in making decisions. An installer might tell you that you don't need to use fasteners in window fins because the caulk will hold them in or that you don't need to use an AIB because the sheathing is good enough.

Local building code officials also can be a good source of information on the performance of systems, as well as on the right way to install them. Other sources can include associations involved in similar work, such as trade unions, or local sections of Association of Building Contractors (ABC).

One of the best quality-control measures we have used is walking the job site as work is progressing and looking around. See if you can figure out things for yourself. If you see something you don't understand, ask someone on the crew (preferably the foreman or superintendent). If you see that someone is installing out of sequence, ask yourself, is it going to work right? Perhaps the worker is doing the right thing, but it’s inconsistent with the design documents. What do you do then? Ask the architect! The one group that should know the most about the way a designed system of parts should go together is the design firm. RFIs are the right way to document the question. An RFI should be generated to ask the designer for additional guidance or feedback. The best RFIs are complete, well written, and list reference drawings. Many RFIs should contain a copy of the section of the reference drawings that is in question, with circles or arrows clarifying the desired information. It can be as simple as asking for more dimensions to lay out a wall. If this is the case, draw a line with arrows or tick marks, and put a circle where you want the dimensions --. RFIs that are poorly worded, confusing, and/or not accompanied by a sketch often take longer to answer and may in fact produce an answer to a different question than was intended. RFI answers should be posted to the contract drawings in both the design and construction offices. Any RFI that affects life safety or structural integrity typically will get signed and sealed and provided to the permitting agency.

MANAGING CHANGE

Managing the changes that may occur in more than 3 years of design and construction can be a task in itself. Controlling the process is important as far as keeping the project on schedule and under budget and maintaining the integrity of the building envelope are concerned. Over this 3-year period, thousands of decisions must be made by a variety of team members with different back grounds and interests. From the earliest concept drawings and schematic estimates, each successive stage requires further development of the concept and further refinement of the design. After bidding and award, changes are made during buyout of subcontractor contracts, in development of submittals or shop drawings, and every day on the job site. Two-way communication is the best defense against changes that can come back to cause trouble. It’s important to document change by written notes, issuing memos and minutes from meetings, copying sketches, and correspondence, to all team members affected and by changing the plans and specifications.

Keeping track of changes made in the plans can be accomplished in many ways. Different firms have chosen a variety of means for documenting changes.

The set of plans that are approved for construction by permit review authorities typically get a stamp of approval by that agency. Those plans should be updated as any substantive change occurs. One way is by marking on them the date and reference RFI that changed them. Another is to copy and paste the RFI answer on the plans, perhaps on the back of the preceding page so that notice it when the plans are open.

It’s the responsibility of the three project management team leaders to make certain the changes don’t result in unexpected or unacceptable envelope performance. The owner, builder, and designer all have a stake in the final performance of the completed project. The liability for future problems can reside in any or all of the firms involved. Most important to watch out for are potential reductions in performance of roof, wall, floor, foundation, windows, membranes, flashings, insulation, sealants, and HVAC systems. If the team successfully manages change affecting these critical components throughout design and construction, then the envelope should have the best chance for great performance over time.

We have touched on the ASI and RFI processes, directives, RFPs, and many tracking mechanisms for change. This is an appropriate place to elaborate on change orders (COs). Some large projects may have 2,000 or 3,000 thousand RFIs. Some of these have a potential impact on time and money. Contractors and especially subcontractors need to be paid extra for approved items without waiting until the end of the job. Change order requests (CORs) or requests for change orders (RCOs) can be used by the GC and CM teams to provide item-by item tracking of several separate items. These can act as shopping lists for the owner to pick and choose from. Those that get approved can be combined into one monthly change order. Once change orders get approval signatures from the three parties (i.e., owner, architect, and builder), the approved values can be added to the contract sum. Contractors submitting monthly payment requests (referred to as pay reqs) then can include the approved scope items in their invoices. By keeping up with project costs in this manner, managers can avoid surprises when the project approaches closeout. Managing total project costs by adjusting contract sums on a monthly basis can prevent having to cut scope during the end of a project when there isn't much work remaining.

QUALITY CONTROL and QUALITY ASSURANCE

The theory of design and building are one thing. Once people get involved in the real world, nothing is quite as clear and simple as it was in the office. All the good intentions and great program and design ideas now need to be built. The dynamics of the workplace make it much more difficult to build buildings in the real world than in a laboratory environment. Starting with the first construction-related activities, each person who performs work can affect the next person's success.

The layout crew needs to convey locations and elevations of building corners to the site-work people. Excavation, fill, and compaction all can have an impact on future structural systems performance. Application of subgrade membranes is the first critical component installation that must be observed closely. Depending on foundation design and the selected membrane, installation can be as easy as stretching out a sheet of plastic. On the other hand, membrane installation can be quite challenging. Maintaining a complete and uninterrupted protective membrane can mean sealing hard-to-reach penetrations as well as coordination with forms and shoring.

Take and study photographs of the process, and forward them to the manufacturer's representative or waterproofing consultant if you have any concerns regarding work that is proceeding.

Protection of the membrane, once placed, can be even more challenging. If allowed, we recommend using concrete bricks to space structural steel above sheet membranes in lieu of metal chairs. Chairs create concentrated loads into sharp metal corners. You might not see any damage on inspecting the rein forcing steel. If you do, it can be patched up. Most damage is done by workers walking on the steel during concrete placement. Only once have we seen a crew stop placing concrete in an area where the membrane was punctured long enough to fix the tear.

It’s always a good idea to check a slab-edge form for level and square before placing the concrete. Check for square the day before, and check for level right before the concrete goes in. Edge forms can change elevation from people or machines imparting loads on them. If there are underfloor membranes that need to lap vertical-face membranes, make sure that the laps are in the right direction. You would not want water coming down a wall membrane to get behind a slab membrane. If you are using a bentonite-type product, we have been told that the lap direction doesn't matter. Just in case, lap bentonite products to avoid backwater laps. Make certain that adequate fastener spacing is used to hold the bentonite mat strips in place until backfill is complete. Watch the backfill process to make certain the mats are not damaged by equipment operation.

Compaction of fill should be done in lifts to ensure that the fill is tightly pressing the bentonite side to the concrete. Make sure that sealed laps in rubber or plastic sheet membranes are clean and sealed properly. Avoid backwater laps in sheet membranes in case the seal is not 100 percent watertight. Laps below the water table typically go in the opposite direction than above the water table because water will be rising up toward grade.

If strip footings are used with CMU stem walls and floating slabs, this should not be below seasonal water table elevations. Floating slab edge conditions typically get expansion joint material treatment that is not acceptable for use with hydrostatic pressure. Watch as materials get delivered to the project site to make sure that the materials are in good condition when they arrive, are not damaged during unloading procedures, and are protected from the elements during and after receipt. Require concrete and brick products to be delivered on pallets, with plastic protective wrap. Don’t allow unprotected block cubes to be placed on the ground, where some CMU get in contact with contaminants that can fuel future mold growth. This goes for interior building materials, as well as exterior wall components. Air-conditioning equipment and ductwork are very important, along with paper-backed or wood-based sheathings.

Look closely at the details for subtle things at the intersections of exterior walls with ground floor and grade. If slab-edge recesses are shown, the starting and stopping points for the pockets need to be coordinated with doors. If there is a detail calling for flashings or a water stop, make certain that they are carried out. Review the drawings for coordination between finish floor and finish grade elevations. Make sure that exterior wall sections provide a means for stopping water intrusion between floor and wall --. Look at where water will go if and when it encounters the vapor barrier.

--- Wall designed to stop water penetration.

Depending on the structural and skin systems selected, work may proceed in many different sequences. Assuming that we are building a load-bearing exterior wall system, we can watch alignment of exterior wall materials with the edge of the slab to avoid cantilevered framing, which can provide easy pathways for water --. Before air or vapor barriers are installed, look to see that all electrical, mechanical, and plumbing penetrations have been either installed or planned in order to avoid future penetrations of the completed barriers. If air barriers are used, make certain that laps are proper. Since the air barrier needs to be a complete, uninterrupted system, make certain that the air barrier is sealed to the edges, sides, bottom, and top. Plan for future airtight seals for any portions of the work that may not be complete, such as soffits and fascia. Look for things that don't make sense, such as wall membranes that might not have been shown where needed. It’s often much easier to see something left out as the building goes up than it was from the computer workstation.

--- Avoid poor alignment of finished

If a vapor barrier is used, make sure that the materials to which it will be applied is ready to receive it. For sheet membranes, make sure that primers are applied to nonporous materials and at laps. Make certain that window wraps are installed the right way, sill pans are placed in sequence, and everything fits.

Make certain that gaps left for sealant are uniform and of the right size and shape. Make sure that fasteners are installed so as to limit undesirable movement when subjected to wind loads and other dynamic forces. If liquid membranes are to be applied to masonry units, make sure that the block was struck smooth and not tooled. Look for defects in the block or cracks in the mortar that may reveal structural problems and could cause problems in the future. If CMUs have been knocked loose or their mortar didn't bond to both sides of the joints, have that fixed before the membrane goes on. If a sheet membrane is used above grade, look to make sure that the installation is fully adhered to the substrate. Watch the workers as they roll the SAMs with the special tool. Make certain that membranes drip over flashings below, not behind them.

This kind of attention to detail does not come without effort. You must make time to walk the project site and look at plans and shop drawings.

Do research about products you aren't familiar with. Avoid substitutions.

If substitutions are made, take extra time to study the way that change could affect future trades. Don’t accept fin-type windows if the details call for something else unless and until you have looked at what the change does to the performance of the systems. Require the design team to redraw the details affected, and issue revised details to the field for construction. Don’t accept verbal acceptance and expect that to close the issue. Don’t think that this kind of change can be covered in as-builts at the end of the job.

--- Workers field modified sill pan to the point of ruin.

Wall flashings must be installed in the right sequence for water to cascade down harmlessly. If flashings are not installed properly, water can get in behind wall membranes. Think about wall flashings as a way to get water from behind one material to in front of the next. If a wall finishes subcontractor is ahead of the flashing subcontractor (often the roofer), then changes may have to be made in the original detail --. In this example, the stucco crew wanted to go before the flat-seam metal roofing was installed. The detail was drawn initially with the stucco J-bead being installed after the roofing was on and flashed to the wall. The detail was redesigned to allow installation of a counterflashing the roofer could tie into later --. This permitted the wall moisture reduction barrier (MRB) and stucco J-bead to be installed before the roofing installation, even though this is not what was intended. This kind of work-around allows trades to keep moving even if others are finished ahead of them, as was intended in the design documents. Even more important is the fact it did not result in a detail with poor performance.

Look for sill pan installations to make sure that the fit is right and that lapping of materials and placement of shims, backer rod, sealant, and fasteners are as intended. The sill pans had been delivered a little late. The subcontractors had cut up the wall membrane and cut important components off the sill pan to try and make it fit the opening.

Check the fasteners to see that they are the same material, size, and con figuration. If 300 series stainless steel fasteners are specified, put a magnet up against them as a field test. The magnet should not be attracted to the fastener because 302, 304 and 316 stainless have such low iron content.

Check to see that fasteners are spaced as required, that they are fastened into the desired material, and that they are not causing deflection in the fastened material, etc.

--- Plumbing vent stack.

--- Void in asphalt.

--- Coping photo with no saddle.

--- Louver installed too close to roof.

--- Plumbing vent stack detail. Welded S. S. Cover; Stainless Steel Clamp; Vent Pipe Flashing w/Fasteners Per Manu.; Sealant Cap Membrane Flashing Plies (2) Strip in Plies Field Cap Membrane Ply Vertical Base Membrane Flashing Ply Second Cut, Staggered from First Membrane Cuts.

First Membrane Flashing Ply Target Base Sheet Membrane Coverboard Insulation (If Required) Thermal Insulation (If Required) Roof Deck Minimum 2" Vent Pipe Anchored to Roof Deck

Look for things above the roof that don’t look right. It might be a good idea to look for things you reported earlier that were reported to have been fixed.

You may find something interesting, such as a plumbing vent stack that is too low to the roof --. On a flat roof, a new boot can be applied and sealed easily around the perimeter. Our favorite detail calls for stripped-in membrane to be hot mopped up the face of the stack boot with a termination clamping ring. A one-piece flashing ring welded to the boot flashing is a long lasting solution --. Other things to look for are voids in the membrane or areas that might have been filled with liquid asphalt roofing cement rather than covered with a membrane product. -- the void caused by shrinkage of a 4-inch-deep asphalt fillet that was so large that we could put a pocket knife in the crack. This kind of crack allows a lot of water in somewhere, and it would be difficult to find from below.

Look for copings that should have had saddle flashings --. You may remember the saddle flashing discussion and detail from section 4. The saddle was to have been installed behind the wall membrane, and behind the metal siding (not surface applied and sealant applied). On a recent roof walk at substantial completion, we discovered an air intake louver whose sill was within 4 inches of the roof surface --. We had mentioned this, months earlier and had been assured that every effort would be made to remedy it. Even more troubling are big, obvious concerns, such as a chunk of tilt wall that had broken off the panel when being erected --. The con tractor had 5 months to patch that panel before paint and roof-edge metal went on. This is unacceptable and is evidence (in our minds) that the superintendent didn't walk around enough. We would rather believe that than think that he knew it was still there and his subcontractors hadn't fixed it, and he let it go.

Taking frequent walks around the job site also has an overall quality-assurance effect that is immeasurable. When workers see you walking around looking at their progress, and you express a genuine interest and concern in what they're doing, it can have a profound impact on their attitude. When you walk around trying to help coordinate things, perhaps asking questions, trying to learn, and not pointing fingers, most workers will take a little more care in what they do.

This attitude can spread through all levels of workers on the job and have a unifying effect. This kind of team attitude can lead to better two-way communication. If one worker comes up to you with a question that might not have been asked, it could result in the avoidance of a future problem.

--- Corner of wall missing.

PUNCH LISTS

At some point, typically near substantial completion, a punch list is generated that is intended to contain each and every item that is not compliant with the contract documents. Some punch lists go beyond this to include personal preferences and "wish list" items. If the team is proactive, the punch list is short because issues that have come up all have been addressed by this time. We have seen 200-page spreadsheets generated from punch-list walks. This usually indicates that the contractor is not complete and may be using the punch list for something other than it’s intended. A punch-list walk should be scheduled after the contractor has done his or her own list and the subcontractors have completed the vast majority of listed items. An exception might be a task that requires several steps, such as three-coat stucco and paint to repair some thing damaged by equipment.

--- Standing water on roof.

--- Voids in envelope.

A punch-list walk should begin at one level, such as the roof, and work its way down to the ground. Life safety, structural, and building envelope observations are the most important to identify. You should look at roof membrane installations after it has been flooded or after a rain shower. Many of us like to look less than 24 hours after a rain event. Any water that is still standing on the roof long after the rain stops can be problematic and must be reported and remedied.

Look for properly sealed laps in membranes --, roof drain installations, and any obvious voids. Measure the heights of louvers, vents, flashings, and other accessories above the level of the roof membrane. Of course, these should have been reported earlier and fixed by now, but you never know. Access hatches and skylights, inside and outside corners, and overflow scuppers should be inspected for tears, fishmouths, or other visible defects. There should not be any standing water or puddles anywhere on the roof-certainly none deeper than a quarter of an inch. If you can put a coin (preferably a penny, dime, or quarter) on any surface ponding, it should not cover the quarter. Look at flashings and copings. Look for ways that water can get behind or under roof products. It’s always a good idea to review the plans and submittals before starting the punch-list walk and to take the plans with you.

After the roof is complete, perform a comprehensive evaluation of wall, window, and door areas. Look for workmanship, adhesion, flashings, and proper laps, fasteners, etc. Some things will be obvious, while others may not be readily seen. Look for closeness of fit and finish between all component parts that make up the building envelope. Even in a cavity wall system, look for voids that can be easy pathways for wind driven rain --. Again, most of the potential water-intrusion problems should have been seen during the installation of materials and fixed by now. Most won’t be visible at the time of the punch-list walk. Notice sealants and flashings, weeps, vents, control and expansion joints, and other exposed pieces of the puzzle. Review water test results, and if possible observe the test in progress.

TEST and BALANCE

Mechanical systems should have been running for some months by now.

Hopefully, precautionary measures were taken to prevent dirt and contaminants from coming into ducting, cooling coils, and grilles during construction. A thorough test and balance (T-B) report will list every fan, pump, valve, and grille in the completed systems. They should have compared actual with design values and made adjustments as required to meet design criteria. This may require replacing sheaves on fans to get sufficient volumes and pressures of moving air.

Similarly, pump outputs and water temperature (if applicable) should be very close to design values. If a T&B report does indicate that nearly every diffuser has exactly the value it was designed to have, ask to see a representative few retested, selected at random. If the numbers are too close, they might not have achieved real test values. If they can't get close to design values (within about 5 percent), the system needs to be remedied. The designers and installing sub contractors need to figure out the problem and fix it.

It can be difficult for a T-B firm to create loads with which to test system performance. Buildings that are tested in the spring or fall won’t have the ambient air temperatures to challenge the capacity of chillers. Values such as chilled water supply temperature won't be as far removed from returning temperature as they would with a 100ºF outside air temperature. Building control systems can be thoroughly tested, though. They should be run through every operational scenario anticipated, and operation of each heating and cooling element should be confirmed. You may choose to recommend a retest of the system after 4 or 7 months when loads are at peak values.

ONE-YEAR-WARRANTY TOUR

It’s usually a good idea to schedule the warranty tour with the owner, builder, and designer all present. This can be a good way to continue the relationship you worked so hard to build for 2 or 3 years. It can be a very cordial walk, with no problems to report. This can be a nice culmination to the effort put forward by all. Conversely, you may find components or systems that show signs of impending failure. Maybe the roof membrane is tearing at the inside corner by the stairs, or maybe the sealant is coming loose from the window jambs. This is a good opportunity to show the owner that you are on his or her side, looking out for his or her best interests. Maybe you can list a few deficiencies and have the subcontractors come back to fix them at no cost to the owner. This can be a great way to strengthen the relationship and will improve your chances for repeat business. Beyond this, this is the best way to prevent future problems that may come back to haunt your firm.

Look for evidence of water intrusion, condensation, or discoloration. See what the owner has changed since the building was completed. Ask about occupant comfort; see if there were any complaints about office temperatures that couldn't be improved by control set-point modifications. Ask about any maintenance or repair issues that have come up. By learning what worked well and what didn't, you can create your own lessons-learned memo to share with your design and construction staff. This kind of feedback loop can reduce future problems and build the kind of reputation we are all striving to have and to keep.