Help with drain tile

[hilandsc]

I have a split entry style house with 5 course concrete block. The land is ice age lake bottom with sand as the base. Footings are in pure sand. Is it necessary to use the 2 inch of rock below the drain tubing(tile) and how far above and out from the drain tubing should the rock overlay go. (This website says 6 inches above and 1 foot out from footing. Is this a minimum or a level that is adequate?)

The land above the footings and around the house is fill with varying amounts of sand, some clay, and just plain dirt--whatever came in on the truck. Horizontal subterrain water flow to the concrete wall is the problem. (water permeates the concrete block either through hydralic pressure or temperature difference in the summer)

Plan to corrrect with Platon on block walls and drain tile at footings.

Any help or experience would be much appreciated

Thanks

Steve

[Wgoodrich]

I suspect there is a lot of info on your soil texture to the depth of your basement walls to the footer that you don't realize.

While you may have sand which is a fast perk soil you may have a glacial till or clay barrier stopping the water during rains and seasonal high water times from perking below teh basement where it would do no harm.

Example if you had borings done by a soil scientist which if rather inexpensive and quick report back to you, highly advised to eliminate the guessing game often experienced by the unknown. Say you have a class one soil of gravel or coarse sand to a depth of 25' deep well below the basement floor elevation. You would then not even need a perimeter drain.

However most often you have a fast perk soil and a mass such as clay that is a barrier to perking the water on down. Say the coarse sand type soil is 7' deep and then a layer of clay is found. You just created a fast perk 7' deep underground swimming pool that has no ability to perk below the basement eleveation. The rain water then would perk quickly down to the clay as a barrier. Then the water can perk no lower. This water then has no choice but to perk horizontally rather quickly directly to your basement walls. If you had the above soil texture make up three high gpm brush pumps would not be able to keep up with the influx of water attacking your basement.

Then consider a perimeter drain ran around the house at the footer elevation then ran into the basement from both ends of that 4' inch perimeter drain pipe. Consider 4" drain pipe has approximate gallon per minute capacity of 300 gallons per minute per 4" hose. If you ran both ends into a sump pit inside your basement the first rain you would find water boiling up about 3' above the basement floor at a rate of about 600 gallons a minute. A terrain type pump with a 100 gallon a minute capacity that would be 1/6 enough to keep up with those two pipes entering your basement will cost approximately 800 dollars for just one pump with about 7' of head. Then once the water reaches the surface of your finished grade where would all that water go.

Before a basement is built a soil boring test should be done to get a report of your soil texture and seasonal high water then you can get an approximate how much water is going to attack your basement. Then you can size your needed pump or pumps to keep the subsurface water artificially lowered below you basement floor to ensure a dry basement.

Go back to the link on the right of this page "building" then click perimeter drain and you will find an article that is an exact copy of the section included of the IRCode book discribing in detail the requirements of your perimeter drain design. This copied section is a part of that article that will explain the above and general design with pictures of a bad installation and a good installation.

I suggest you contract a soil scientist approx cost 75 to 150 dollars a boring that will provide a report to the depth of your basement footer. Then you will know what you are dealing with and how big of pumps or gravity drain outlet you will need to artificially lower the water table in adverse flooding conditions for the life of your home.

HOpe this gives you a minor picture of design needed.

Good Luck

Wg