WATER DRAINAGE PROBLEMS-- FRENCH DRAINS?
WATER DRAINAGE PROBLEMS-- FRENCH DRAINS?
(OP)
I am needed a little advise on what to do with a water drainage problem in my house. I bought the home from the heirs of the original owner so there was little to no information on any problems with the home. Shortly after I moved in I noticed that everytime we get a good rain, I get about 100 gallons of water in my garage (I know this because I have a wet/dry shop vac and fill it up several times after each hard rain). After closer inspection of the perimater of the north side of the house, I noticed that this problem has been happening for at least a little while. Either my foundation has sunk or the previous owner has built up the ground to high. The ground around the house is higher than the foundation line and half way up the second layer of brick covering all weep holes. The level of the yard on the back of the house is relatively flat. The level of the yard around the adjacent corner is built up a bit toward the house probably to help channel water away from that side. But I need to a least take down the yard a bit to expose the bricks and weep holes, and probably a little foundation. If I remove ground (about 8 to 10 inches) to allow the foundation to be exposed then I will create a fairly noticable slope toward the house bringing in more water. My question is what system can I put around the perimater of the house to flow the water away after I take down the yard? Also, I should note that my neighborhood is built on possibly the worst possible soil for foundations. I think they call it black gumbo. During dry seasons, everyone actually waters their foundation with soaker hoses to regulate swelling of the soil and prevent cracking of the foundation. I want to be able to prevent rain waters from comming in, while maintaining a balance of moisture in the soil for my foundation. P.S. My bad soiled neighbor is located in San Antonio, TX.





RE: WATER DRAINAGE PROBLEMS-- FRENCH DRAINS?
Just keep the basic principles clear: The best solution is to grade the peremeter soil away from house for at least 10 ft and have a trench to catch and divert water around the house. Ideally, it could be a wide open trench, but that's usually not practical, so you want to fill it with material that will still let the water move through it and that will keep crud from plugging it up.
We dig the trench at least 36 inches wide and 16 inches deep. The slope of the pipe is crucial to the success of your French drain. So the grade is very important. The trench should slope at least 1/8 to 1/4 inch-per-foot towards its outlet. Lay geotextile, a permeable non-degrading fabric leaving enough to overlap 12 to 18 inches at the top. Spread two inches of gravel or rock (3/4 or 1.5 inch) on the bottom. Locate and install two or three collection boxes as appropriate. Then lay three 6” perforated drainage pipe (function of runoff flow) wrapped with SOCKS in the bottom. If the pipe is perforated on one side install with the holes in the lower side. . Tie the collection boxes into only one of the pipes. Then fill with crushed stone to about 6 inches from the top. I put about 2 inches of pea stone next (small crushed stone). Over lap the geotextile fabric and back fill with coarse mason sand.
The reason I like to use more than one pipe is to separate the collection boxes from the collection line. This adds redundance, and the pipe is cheap. The benefits are that the multiple pipes are much cheaper than the gravel, it significantly reduced the quantity of gravel you will need to shovel into the trench, and it creates lots of annular space in the trench to facilitate drainage.
Additionally consider guttering the run off from the house to the drains.
RE: WATER DRAINAGE PROBLEMS-- FRENCH DRAINS?
RE: WATER DRAINAGE PROBLEMS-- FRENCH DRAINS?
I have used the pipes to run the flow to the curb or a ditch.
RE: WATER DRAINAGE PROBLEMS-- FRENCH DRAINS?
RE: WATER DRAINAGE PROBLEMS-- FRENCH DRAINS?
Common construction techinque for modern momoslabs, is to pour a 6"x6" brick ledge extension on the outside peremeter. Typically this is located 11-1/4" below the slab. The thickness may vary but it should be there.