Ultimate Guide to DIY House-building -- Pole and Pier Foundations

A less frequently used foundation is the pole and pier arrangement (Ill. 33). It's a good setup for small homes built in steep terrain, or for vacation homes and cottages. Poles or piers are firmly implanted into solid ground so they're stationary (frequently cemented right into the ground) and then the frame of the house is constructed on top of them. For this type of foundation, concrete tubes (concrete-filled cardboard cylinders) and telephone poles are very popular.

Advantages

1. It lends itself to steep terrain where there is considerable variation in the height of the piers and where a regular masonry foundation is impractical.

2. Grading isn't required. There's a mini mum of site preparation involved.

3. It's an inexpensive foundation and easy to build.

4. There's plenty of natural ventilation between the ground and the living levels.

Disadvantages

1. With the underside floor surface fully exposed to the elements, in cold climates the floor must be exceptionally well insulated.

2. It allows wind and small creatures to get beneath the building.

3. It is practically useless for any kind of storage or future expansion.

A post and pier foundation.

Ill. 33

MISCELLANEOUS...

1. In locations with large populations of termites or carpenter ants, consult a qualified pest-control company to provide appropriate treatment. The company should provide a guarantee on their work that covers repairs if insects re-infest the treated areas.

2. Specify if you want windows in your foundation: their size and make, how many, and their location if in a full or partial basement.

3. Specify if you want a rear or side outdoor entrance to the basement.

Use concrete or steel lintels for door openings. Precast lintels are simple to install because they're made to match the height and width of concrete blocks. They should be long enough to overlap (per building code) on the bearing block. Another method involves forming and pouring a lintel on the site, using wood forms and reinforcement rods.

The outside stairwells should begin at a point lower than the basement floor, to prevent water from entering the house. A 6” sill protecting the basement door is standard. Or, a built-up curb could be constructed as a partial remedy. A decision should also be made if you want the stairwell opening covered by steel doors.

4. Don't let the contractors confuse the topsoil that was pushed to the side when the construction first began with the soil that was excavated for the foundation. The topsoil should only be used for finished site grading, not as backfill around the foundation.

Trees you want saved should be marked with bright ribbons or spray paint so the contractors won't damage or knock them down.

The agreement should specify that all scrap tree stumps and brush must be pulled out and hauled away. If you get your builder to agree up front, hardwood trees that need to be removed could be cut up and piled for firewood.

5. It's not a common request, but poured concrete walls and floors can be colored by the addition (when wet concrete is being mixed) of mineral pigments sold by ready-mix concrete and block producers, lumberyards, and building material dealers. Reds, greens, yellows, browns, grays, and other colors are available.

6. If you're going to have a full basement, and you plan to eventually put in a recreation room, try to locate it as closely as possible to the basement stairs. Opt for larger windows than normal so the room will have adequate light and ventilation during the day.

Check building code requirements related to any partitions you plan to install around the furnace and water heater; you might have to meet clearance and surfacing requirements.

Avoid placing partitions, present or future, too close to plumbing heating-electrical elements such as sump pumps, water meters, shut off valves, and waste cleanouts. Give them an extra inch or two clearance to permit quick access in case of trouble.

When possible, plan a workshop area close to an outside access and also near an unexcavated sheltered area where a crawl space can be used for lumber and storage of other long materials.

The typical cellar wall should be 11 courses high (or 88”).

But if any rooms on the floor above it will be sunken, consider an extra course (12 courses total) in case you someday decide to finish off the basement. If you go the extra block, you'll still be able to have a normal ceiling height when finished.

All basements should have at least one water drain in the floor, and those cellars larger than 900 square feet should have two drains. The floor should taper toward the drains, and the drains should transport water to the house's sump hole or exit drain.

The local building code and the contractor's engineer should specify properly sized steel beams, girders, and vertical columns.

STUFF TO THINK ABOUT...

1. The main goal of a footer is to evenly spread or distribute the weight of a house over a large enough area of soil so that settling or moving of the dwelling never occurs.

2. If the building site you select consists of recently filled loose soil, the loose soil must be either excavated out, compacted through mechanical means, or built upon by custom engineering and construction of a footer for the exact home you are building.

3. The frost line must always be taken into account when constructing footers and foundations. If a footer is not placed below the frost line, the alternate expansion and contraction of the earth above the frost line might cause the footer to move-to heave upward or list downward-causing cracks in rigid concrete footers and foundations, with their accompanying ill effects.

4. The type and condition of the soil must be taken into account; check it by having a soil test hole dug. Organic types of soils (such as peat) groundwater content, and large tree root systems can all interfere with traditional concrete footers and foundations.

5. Paying special attention to the sewer or septic lines prior to construction.

6. Concrete foundations should extend above the final grade enough so that wood members of the house are some distance above the soil, for protection against moisture and insects.

7. Concrete block or panel or poured concrete foundation walls enclosing a basement should be a minimum of 7’ high, from the basement floor, and consider up to 9 feet if you know you'll be finishing off parts of the basement later.

8. Achieving efficient outside drainage around a home's foundation is absolutely critical to prevent basements from developing moisture and leaks. So are good waterproofing techniques, vapor barriers, correctly graded lots, appropriate landscaping and positioning of shrubs and trees, generous roof overhangs, and plenty of gutters and downspouts.

9. Don't allow the contractors to confuse the topsoil that was pushed to the side when the excavation first began with the soil that was excavated for the foundation. The topsoil should only be used for finished site grading, not as backfill around the foundation.

10. Consider the addition of a root cellar and /or storm shelter to be excavated at the same time your home's footer and foundation are being installed.