Should You Finish Your Basement?

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Perhaps your basement is under a modern house, with plumbing roughed in and room dimensions defined: a basement that was built with the intent that it would one day become part of the living space. On the other hand, suppose your basement is little more than a cellar and contains an old- fashioned “octopus” furnace, a coal chute, and racks to hold screens or storm windows depending on the season. Should you finish your basement? If you need extra living space, even the cellar can become attractive and usable space.

One example was a 95-year-old farm house with a cellar roughly 20 feet square, or about 400 sq. ft. of usable floorspace. The owner had four teen-age children and decided to finish the basement as a rec-room to take the wear and tear away from her living room. The contractor was most doubtful of the possibilities when he observed the crumbling sandstone walls, the cracked floor, and the low headroom. But the lady had her own plans for the space: all she wanted was someone to carry out her plan. The sandstone walls were plastered with a stucco-like finish; pipes were moved to make a clean surface for application of a wall board ceiling; and a large hole was cut into the reinforced floor of her living room. A circular stair was installed in the hole and the former cellar became a very attractive extension of the living room above; an extension that isolated noise and pro vided privacy while being in reality only an 8-foot deep “conversation pit.”

While recalling worst-case examples, it's true that some basements simply are not very good candidates for finishing. Make an inventory of the problems in your basement and decide whether they can be corrected before making any decision to invest your time and money.

The Space: How Usable?

The first step is to decide what you will use the space for. Is there sufficient headroom? Comfort requires, and building codes may decree, that your basement have a minimum of 7 1/2 feet of head room. Many houses, especially those tract houses built right after World War II, were built with ten- course basements. This means that the concrete blocks were stacked only ten courses (rows) high, yielding only a scant 7 feet of headspace (ten rows of 8” block, plus mortar joints).

Consider also that steel or wooden support beams which run down the center of the floor can be en closed or otherwise dealt with. But in older houses, where attempts have been made to reinforce sagging floors, one may find support beams and posts that must either be relocated at some expense and effort, or will so obstruct any rational planning as to make the job inadvisable.

Converted furnaces with huge “octopus” ducts may also provide a barrier to a successful basement remodel. If the old furnace is due for replacement and you are prepared to pay the cost of a complete overhaul of the system, finishing the basement may then be worthwhile. Stairway location too can be a problem, but it's not terribly difficult to reposition the stairway if that's the only objection to the project (see PLANNING AND JOB SEQUENCE, Section 2).


Does your basement have windows large enough to provide light and ventilation? Without such windows a basement can be a dungeon. Does the basement have an exterior door, or are windows large enough so that an adult person can crawl through them to escape a fire or other emergency? Your building code may require optional basement exits for basement space that's occupied (see PLANNING AND JOB SEQUENCE, Section 2).

Basement Water and Moisture

Moisture Problems

A common sight for contractors or building inspectors is to find basement windows that have not been opened for many years. Often, one will see basement windows that obviously have been painted shut. This is always the case when one finds strong mildew or mold odors, black mildew stains on walls or undersides of floors, or water stains at low levels on concrete walls, where the walls meet the concrete floors. Owners or occupants often complain of the odors when quite obviously they could be eliminated by opening the windows, perhaps using fans to pull the fresh out door air in an open basement window at one end of the basement and out through another open window at the opposite end. Fresh air, which can contain little humidity on a warm summer day, will not only pick up excess basement moisture and remove it, the air will freshen the interior as nothing else will.

Basement surfaces such as concrete floors and walls are usually cooler than the air, so any moisture will condense when it reaches the cool concrete, and form droplets of moisture. This appearance of moisture forming on cold surfaces is a sure sign that humidity is building up in the basement, and that additional air circulation or ventilation is needed. Not only will the accumulated moisture damage the building materials in the basement, the high humidity is very uncomfortable for the occupants of the space.

Open the windows, and consider installing vents in areas where moisture is present. No pro is impressed with those vent dampers that let the dryer exhaust spent heat and moisture into living space. The heat thus saved is negligible: one obviously should not use such a device on gas clothes dryers or other appliances, and the potential for creating moisture problems in the house is very high. Vent dryers directly outdoors to get rid of the moisture: the reclaimed heat from 3 or 4 loads of dried clothes per week is negligible.

Be aware of the potential for moisture problems when you choose the materials for finishing your basement. For example, use louvered doors in stead of solid slab doors, so moisture will not be trapped in closets or laundry space. Choose open shelves and wire baskets for storing clothes, rather than closed drawers that will trap moisture. Any basement bathroom should have an exhaust fan, preferably connected to the light so the exhaust is running anytime the light is on.

Basement Water

Few problems have provided a greater opportunity for homeowner rip-offs than wet basements. And yet, the National Association of Home Builders has always maintained that the great majority of wet basements are wet because roof and ground water are permitted to run into the basement. The NAHB estimates that perhaps 95% of all wet basements could be dried up inexpensively, usually by the homeowner’s own efforts.

Basement waterproofing contractors maintain that the cause of the wet basement is a “high water table.” The water table is the depth at which the ground or soil is totally saturated with water. A call to your local building inspector, or a local excavating contractor, will inform you where the water table is in your area. Keep in mind that modern building departments seek to avoid problems with new houses, and will not issue building permits for basements if they believe that the water table will cause the homeowner future trouble. Another potential problem is for the building department or city itself: permitting construction in areas where the water table is high causes the city problems with the sewer system, because any water that enters the basement ultimately winds up going down the floor drain and into the sewer treatment facility.

For further convincing, consider this quote from HouseMaster of America, a national network of home inspectors: “Based on HouseMaster of America’s experience, most wet basement conditions could be alleviated with minimum effort and expense. This is due to the fact that most water penetration (into basements) occurs because its major causes rain water from the roof and surface water are not attended to, and water accumulates around the perimeter of the house and eventually seeps in.” The key here is the phrase “alleviated with minimum effort and expense.” This means that you may have problems with roof rain gutters, or with the grade of the lawn around your basement. If the grade (slope) of your lawn is such that it lets water run back toward the basement, the water will find its way into the basement. Use a level and straight 2 x 4 to check the slope of the lawn on all sides of your basement.

Be aware that digging a flower bed or installing a concrete slab for a walk, drive, or patio may disturb the grade that was established by the builder, and you must add dirt to reestablish a good slope on all sides of the basement. Be aware, too, that the presence or absence of roof rain gutters on your house is not significant. If you have no rain gutters it simply means that the contractor checked that particular site for grade or slope, the width of the roof overhang, and the proximity of your house to your neighbor’s house. The builder then decided that the basement would stay dry without having rain gutters: he may have made a bad decision, and some future development shows that rain gutters are needed to collect the rain water and snow melt from your roof and deposit it far away from the foundation or basement walls. Many people will stubbornly assert that the house doesn’t need rain gutters, simply because it has never had gutters: never mind that there has been a long-term water problem with the basement.

If you have gutters and you still have basement water problems, check the condition of the gutters. Gutters that are loose, or sagging, or rusted through can collect vast amounts of water and then deliver it all in one spot, where it can seep back against the basement wall and enter there. Repair, replace, or reattach gutters as needed. Check also to see if the ground pipes are in place and are delivering water at least 6 to 8 feet away from the basement wall. If you observe houses as you drive through your city you will note that many have downspouts that dump roof water in a pool next to the basement wall: there are no ground pipes at the bottom to carry the water away. If you look in the bushes, you may see that the problem is simply a missing ground pipe: the person who mows the lawn just throws the ground pipe in the bushes to avoid having to move it each time he mows. Each downspout can easily deposit 200 to 300 gallons of water against the basement wall: a 1 inch rain deposits 1,200 gallons of water on a 1,200 sq. ft. roof. Replace or add ground pipes.

If leaks persist take a walk around the house during a heavy rain, and try to see the flow patterns the water makes. You may spot a steady stream of water that runs directly toward a wall or window well. Your task then will be to provide a diversion so the water will run away, rather than toward, the house. Solving your water problem may be as simple as installing a plastic cover over a window well, or damming the water’s path with a wheelbarrow of dirt.

Finally, seal all cracks in the basement with patching (hydraulic) cement. Then apply one or more coats of waterproofing sealer to the interior side of the walls, to seal out water, insects, and radon.

(top) White powder or stains at corners between walls or walls and floor indicate efflorescence from moisture problems. (bottom) To check moisture source, tape aluminum foil on the concrete wall Check after 24-48 hours. Moisture on back of foil indicates seepage or leaks; moisture on foil face indicates condensation (high humidity). Basement may have either, or both, problems.

(above) Mix etching chemical into water as directed on label instructions. Etching product etches and cleans the concrete surface. Note rubber gloves; also wear eye goggles for protection. (Below) Use nylon brush to apply the etching chemical to the efflorescence. A 5% solution of muriatic acid can also be used for cleaning concrete.

Use a wire brush and scraper to clean away slag and efflorescence. Wear eye goggles. Fill minor holes and level form marks in concrete with Portland cement or patching product.

Cracks between floor and walls should be filled with hydraulic (waterproof) cement. Widen crack with a mason’s chisel and hammer. Widening the crack permits penetration of hydraulic patching into crack. Use a mason’s pointing trowel to apply hydraulic cement patching to the floor cracks. Note worker is applying patching material at 45- degree angle up the wall.

Drain Maintenance

In the past, homeowners have considered that the proper time to clean sewer drains is after they have backed up into the basement and caused a mess. A much wiser approach is to consider drain cleaning to be a regular maintenance procedure rather than an emergency, after-the-fact job. It is only good sense to clean drains periodically to avoid the damage and inconvenience of water in the basement.

20 Use a nylon brush to apply a quality masonry waterproofer to all walls, as a final insurance against future leakage.

In most metropolitan areas cleaning the main sewer drain (from the house to the street sewer main) involves having a professional run a steel cable device through the 4-inch diameter drain pipe. At the end of the steel cable is a set of revolving steel blades that scrape the interior of the pipe free of grease, hair, tree roots, and other obstructions. Because city lots usually have short set backs (the distance from the front of houses to the curb or street) of under 50 feet, figure a charge of $100 to be at least a starting point for estimating the cost of sewer drain cleaning. The charge obviously may vary widely, governed by such factors as the general economy in your area, whether servicemen are paid union wages, the length of the sewer drain pipe, and whether the pipe is already partially clogged with tree roots, which may take hours to cut through. The best approach is to look for special rates offered by plumbers or sewer cleaning services during winter or off-season times when a non-emergency, routine cleaning can often be had at near half-price rates.

Ask the serviceman how often you should have your sewer drains cleaned. If you have problems with tree roots penetrating into sewer pipes and clogging them, the serviceman may suggest an annual cleaning; if there are no trees to block sewer drains, you might be safe in having the drains cleaned every two years.

Whatever your serviceman suggests, it's wise to follow his advice and observe preventive maintenance with drains. Neglected drains can fill with roots until the cast iron drain pipe breaks. Then, your only option is to have the drain pipes excavated and replaced. Even the cost of sewer drain replacement may be minor, compared to the mess and damage to walls, furniture, and carpets from a backed-up sewer drain.


Asbestos is a known cause of such diseases as lung cancer, asbestosis, and mesothelioma. The evidence is that asbestos-related diseases are most common in industrial workers who have been ex posed to asbestos over a period of years. Even with daily exposure, it takes years for asbestos-related diseases to reveal themselves. There is no recognized safe exposure level for asbestos.

As long as asbestos is not disturbed so that fibers can become airborne, it does not pose a health hazard. If you are remodeling, leave any asbestos products in place if possible. For example, you might just place another layer of plywood over floorcovering that contains asbestos, rather than removing it.

If you remove old ceiling tile in a basement remodeling, or if you decide to replace old heating equipment that has asbestos insulation covering pipes or ducts, you may wish to contact your local Environ mental Protection Agency office for advice. The EPA offers a homeowners’ guide titled Asbestos in the Home. The EPA also has a list of approved Asbestos Abatement Removal Contractors. Don’t fall for any hustlers who are cashing in on asbestos fears.


Radon is a radioactive gas that's odorless, color less, and tasteless, and is generally thought to be second only to smoking as a cause of lung cancer. Radon became an issue when it was found in high levels in houses that were built with materials that had been contaminated by uranium mine waste, back in the ‘60s.

How serious is the risk? The Environmental Protection Agency suspects that radon may be responsible for as many as 100 lung cancer deaths per day. It is believed that the risk increases with exposure. Most risk estimates are based on lifetime or long- term exposure, plus the level of radon contamination.

Radon is measured in picocuries. A picocurie is 1/trillionth of a curie, a unit of measure for radioactivity. The permissible limit for radon is set at 4 picocuries per liter of air, shown as 4 pCi/1.

To assess the risk, consider that one source estimates your lung cancer risk from 4pCi/ 1 to be equal to the risk of dying in a home accident: the risk at 20 pCi/1 radon exposure is equal to the risk of dying from an auto accident. But the jury is still out: recent reports indicate that the state of Iowa may have the highest concentration of radon in the nation, but Iowa has a low rate of lung cancer. What is certain is that radon is definitely suspect; that radon levels are greatest in the basement, and anyone who contemplates finishing off basement space would be prudent to do some preliminary testing for radon.

It is obvious that one factor is the way we live and use our houses. Those who spend a great deal of time in a basement workshop, or who have bed rooms or recreation rooms in the basement are at greater risk than those who spend little time at home.

There are areas where radon levels are known to be high, but radon should generally be monitored on a house-by-house basis, because radon can appear anywhere. And, despite the media attention given to radon, statistics indicate that the majority of homeowners have not tested their homes for radon. If you plan to finish off your basement or even if you don’t you should test for radon.

Home centers and department stores offer radon test canisters containing activated charcoal. Just open the canister and leave the unit in the basement for 3 to 7 days. Then close and seal the canister and send it off to a laboratory. The cost for this test, including postage and laboratory work, can be about $40. Another test device is called an alpha track unit. The test uses a sheet of polycarbonate plastic as a recording surface. The exposed plastic sheet is struck by alpha particles from decaying radon, and is left in place for 3 to 6 months. Then the dents in the plastic are counted by a lab oratory to find the level of radon present. This test costs between $25 and $50. If these low-cost tests show no radon, or show levels under the 4 pCi/1 permissible level, it's safe to proceed. In most cases the level of radon will not increase, but you may decide to retest from time to time to be sure radon levels are safe.

If tests show higher levels of radon, don't panic and let yourself be the victim of any radon control rip-offs. One home in an area known for high radon levels, the “Reading Prong” in New Jersey, showed radon levels at 3500 pCi/1: a contractor reduced this level to 2 pCi/1 in one day’s work, for a total cost of $1,300. If radon levels are high, contact your state radiation protection office for further advice.

Remember that the repairs recommended for radon control are good basic procedures to control air infiltration and moisture and insect entry as well. Caulk or patch (with hydraulic cement, if there is also a threat of water seepage) any cracks in basement walls or floor. Then apply a coat of waterproofing sealer such as United Gilsonite Laboratories’ (UGL) Drylok to all walls. Install ducts so that furnaces, fireplaces, or dryers can draw outside air for combustion or for drying. Appliances that draw combustion air from the interior will create low indoor air pressure and in crease radon infiltration.

Provide ventilation so that fresh air continually flows into and out of the basement. There is almost no health threat that's not decreased by good ventilation: radon, moisture/humidity and chemicals such as formaldehyde all are reduced or eliminated by continuous ventilation of the basement or workplace.

Some states or local governments offer free radon detectors: your local building inspector should be able to help you locate the right office for radiation protection. Or, call your regional Environmental Protection Agency office, as shown on the next below.

Effect on Resale Value

A common subject for discussion on homes has been the effect of certain remodeling projects on resale value. Finishing a basement can return the project’s cost or more, depending on whether you do it yourself or pay contractor prices if the basement is a walkout or daylight basement. Walkout or daylight simply means that the basement level is partially exposed, so that doors and windows open onto ground level or grade. If the basement space is below grade so that no ground level entry door is possible, and windows are high and small so they let in little sunlight, any return on remodeling investment will be limited.

If you do most of the remodeling work yourself, so the cash investment is for materials only, you should get back a marginal return. If you pay contractor’s prices, you will be fortunate to get back 100% of your investment. Many texts treat a 100% return on remodeling investment as though that return was a worthwhile goal. But, getting back 100% simply means that you have traded dollars: you have not made a profit. There is no profit in sticking $6,000 into a project, simply in the hope of getting it back out. You are better off to leave the money in a bank than undertake the remodeling.

Let’s illustrate the point: Two divorced women lived in houses exactly alike and side by side. Both had divorce agreements with ex-husbands that they would occupy their houses until minor children graduated high school; each house would then be sold and the proceeds split between the woman and her ex-husband.

Both put their houses up for sale at the same time in the summer of ‘89. One woman listed her house for $74,900. She did no work on the house to ready it for sale, nor to try to increase the sale price. The neighbor called in a contractor and finished off the basement at a cost of over $6,000. By doing this she hoped to increase her final profit, and listed for $84,900. The results? Both houses were slow to sell. But the one with the unfinished basement sold in about 90 days, for $73,000. The house with the finished basement and the higher price sat unsold for months. Finally, the house was sold for $78,000, or only $5,000 more than the house with the unfinished basement.

What was the effect of finishing the basement and setting the higher price? First, the seller increased the asking price so the house was offered at the top of the scale for houses in that area. Next, she forced the buyer to come up with a slightly higher down payment, and the house would have slightly higher monthly payments. Also, she increased the agent’s fee by $700 if she had gotten her asking price, it would have increased by 7% x 10,000 or $700.

Not only did the woman who remodeled not get back a profit for her investment, she actually may have made the house less desirable than if she had left the space unfinished. Many young couples, looking at unfinished space in a basement or attic, see the space as an opportunity to save money by doing the work themselves. And, if they don’t need the space, they will see the higher price as a barrier to buying the house.

There are no rules in real estate. If you’re a smart buyer, and a good planner, you may succeed where others would fail. The best advice, however, is to finish basement (or attic) space only when you need the space for your own family, and only when you intend to stay and use that space for a period of at least several years. The use of the space constitutes a return on your investment, and a well-executed basement remodeling should yield back at least as much as it cost — or more, if you do a good job of planning and executing your remodel.

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Updated: Tuesday, June 4, 2013 23:17