French Drains – Earthwork/grading Engineering – Eng-Tips

The aging process ultimately ends the ability of sealants to block out soil gases. The lower the air pressure in your house, compared to that in the soil, the more radon-laden air may be drawn inside from the underlying soil. If these drain tiles form a partial or continuous loop around the house, they may be used to pull radon from the surrounding soil and vent it away from the house. Subsurface water would much rather travel through gravel and open drain pipes than force its way through the soil. Water is drained away from the foundation of some houses by perforated pipes called drain tiles. While some types of these drains include a perforated drain pipe (sometimes called drain tile) and may be covered with grass, the traditional French drain is simpler and easier to build. This method may have effect on radon entry unless nearly all the entry points are sealed.

If openings must be made in the upstairs floor, the openings should have a reasonable cross-section to avoid suffering a severe energy penalty. Operating costs should be roughly $30 per year for fan electricity and $100 per year for the heating penalty resulting from increased house ventilation. The annual cost for operating a fan would be about $30. Installation of drain tiles in houses that do not have them is sometimes not cost effective. In some houses, the installation of a drain-tile suction system has resulted in radon reductions of over 99 percent. When sealing is used alone, you should expect only low to moderate reductions in radon levels. Because each situation is different, it is impossible to predict the reduction in radon levels that can be expected as a result of reducing sources of depressurization in a house. Drainage in pretty much every situation be it domestic or industrial, water or waste is a critical thing.

Our page top drawing of types of indoor foundation and basement drainage systems is provided courtesy of Carson Dunlop Associates. Also, the openings in the top row of concrete blocks in a wall are often inaccessible or otherwise difficult to seal tightly. It can enter your house through: openings around utility pipes, joints between basement floors and walls including perimeter (French) drains, other floor drains (especially those that discharge to dry wells), the holes in the top row of concrete blocks, and tiny cracks and openings (such as the pores in concrete blocks). If possible, the holes in the top row of concrete blocks in the basement walls should be sealed with mortar or urethane foam. Check the municipality permits or authorizations you need and think of creative ideas to build on top of the drain. These include: the top of block walls, the space between block walls and exterior brick veneer, and openings concealed by masonry fireplaces and chimneys. Porous walls (especially block walls) require the application of waterproof paint, cement, or epoxy to a carefully prepared surface. We have a block and beam foundation, clay soil, no gutters and we end up with pools of water right next to the house and sometimes covering most of the back and side yard.

A backhoe can cut a deep, wide trench quickly, but you’ll need to plan how to get this big, heavy tool into your yard. Perimeter drain (French drains) should be filled with a urethane foam; however, some alternative plan for water drainage should be provided. Some homeowners, however, might be able to install a drain-tile suction system themselves (particularly where work inside the house does not require removing concrete). If some portion of the perimeter footing does not have drain tiles beside it or if the tiles are damaged or blocked, that portion of the perimeter might fail to be effectively treated. Clear any blockage at the end of the footing drain extension, open and check the end for water flow in wet weather. Use gravity to avoid back flow and install the proper check valve in the sump pump discharge circuit. Check if the French drain you are installing isn’t causing problems to the neighbors when it comes to the groundwater runoff.