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I am interested in finding out how a crawl space drain is installed on a pitch so that excess water drains to an outlet drain. Since the footing is suppose to be level, the drain can’t follow the contour or it would be level. Yet, the books that I have read say to install it that way with no discussion as to pitch. Is it common to also have an electric pump if one cannot get the outlet drain to pitch? Are there regions in the country that do not install drains at all?
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Normally you install the drainage pipe on the outside of the footings. Starting at grade at the extreme side away from the outlet and sloping as you progress towards the outlet.The highest point should be below the grade of the slab base and the outlet should be on average about 6 to 12 inches below that.
The idea is to have drainage at a level below the grade of your slab so that the moisture or water doesn't seep through the slab.
Gabe
*Greg. Gabe gives good advice. However, if the drain pipe is laid on relatively flat ground, water will not accumulate at the base of the footings as lonmg as the exit point to daylight is sloped downward. GeneL.
*Thanks Gabe and Gene for your input. To follow up though, what happens if your building lot is graded flat. For the footing to be two feet below that grade, how is one to get that needed slope to the street? You would be under the street. Under those circumstances, is a catch basin and pump necessary?
*Greg, If your lot is serviced, depending on local bylaws you may be able to hook up to them and that will be well below the grade of the lot. If rural or with an elevation problem, you will have to install a sump pit and pump.Gabe
*Greg: You have described a situation my son faced in Illinois. His house was in an old soybean field, hence, everything was flat as a billiard table. he had a problem w/ water in his crawl space every winter. There was no way at all that he could drain by gravity out of the crawl space since the floor of the crawl was about 2 ft below grade so the footers could be below frost line. The solution we came up with was to place a drain along the outside wall at the base of the footing to intercept the water as it approached the house. The footer was about 36" below grade, and the concrete block foundation walls were not parged when the house was built over 10 yrs ago. We parged them, to say the least. Since the new outside drain was already lower than the surrounding terrain, we had to go under the footer, build a drain line sloped into his sump and pump the water back outside and dump it well out from the house. As a reference for the construction of this system, we used Paul Brickell's "Great Escape." His sons loved the reference, and the story as I related it to them while tunneling out of the Stalag. Even rented the video after we were finished. Took daughter-in-law and grandsons about 2 months to dig the outside trench, and son and I over a week to do the inside trench. Also took about 5 tons of gravel, 25 buckets to move waste dirt out and gravel in. He hired someone to remove the waste dirt - a pile about 10 ft in diameter and 5 ft high. I grew to hate the plumber and builder that placed the HWH in a position such that the gas line ran right across the center of the crawl space entry. I cursed them both every time I went in or out and whacked my back on the pipe - approximately 2,587 times. Was it worth it and did it work? You betcha!! He had the only dry crawl space in the neighborhood, and it helped him sell house in three days after putting on market. Even made a bit of profit. Our labor was charged at about ten cents an hour.
*Don, Thanks for your input. It requires more thinking than one would expect, yet so critical. Shame on the builder. We need a heading to post the different builders names and locations and their severe errors for all to see. GW
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I am interested in finding out how a crawl space drain is installed on a pitch so that excess water drains to an outlet drain. Since the footing is suppose to be level, the drain can't follow the contour or it would be level. Yet, the books that I have read say to install it that way with no discussion as to pitch. Is it common to also have an electric pump if one cannot get the outlet drain to pitch? Are there regions in the country that do not install drains at all?