Flooding in crawlspace. Other solutions besides encapsulation?

[Jimmy Chao]

My crawlspace is constantly flooding from heavy rain. From what I've been told, the soil in the region (Kansas City) soaks up water, which is how its getting in crawl space. A foundation/water proofing guy told me the best solution is encapsulation with sump pump which is going to cost nearly 20k. Has anyone else with crawlspace dealt with this problem and what fixes did you do?

[JD Martin]

Water's not getting in because the soil soaks up water. Water is getting in because water both seeks its own level and seeks the path of least resistance. If there's a major impediment to it seeking its own level, it will back up until it finds another path of least resistance. This is why we can build hydroelectric dams and canal locks. We put a major impediment into the path of least resistance, and water backs up until it finds another path of least resistance, then takes it seeking its own level (hopefully that's a spillway instead of a ruptured dam!).

So now to bring it back to your house - water is draining on the ground from the roof and from the sky, it is running on top of the ground and running underground. In order to keep your crawl space dry, your crawl space has to be both out of the path of water seeking its own level and a greater point of resistance than anything around it. That sounds pretty daunting, but luckily most issues (other than a very high water table) are solved with very little money unless you're allergic to a shovel and a few hours of manual labor.

1. All gutters need to drain as far away from your house as possible. If you have a nice steep pitched ground going away from your house everywhere (doubtful with a wet crawlspace), you might just get away with a splash block, but most people are better off piping the downspouts at least 10-20 feet from the house, draining to daylight and taking advantage of downhill geography from there. At least half of all wet crawlspace/basements is because you're flooding the ground around your house with all the runoff from your roof which massively increases the water load of the soil around the house.

2. Grading around your house needs to be pitched away from the house in all directions. Your house should sit on a little hill. Even if that hill is 6 inches higher than the rest of your yard. Surface drainage is going to account for most of the water that wants to get in. This is sometimes really difficult to achieve if you're in a really flat place and they didn't give you enough cralwspace/basement block to grade properly.

3. If you can't solve #2 with a shovel then you try to solve it with a perforated pipe and gravel (or peanuts) commonly known as a french drain. The idea is you create a path of virtually no resistance that's easy for water to get into so that it goes in the direction you want it to go. Usually you'll do this all the way around your foundation and find a good (downhill) place to dump the water. If there's no downhill, you dig a really big empty hole far from your house, fill it with gravel, and let the pipes dump into that hole. The water will back up in that hole, but it's not backing up into your crawlspace.

4. Sump pump is a feasible idea when everything else has been done and you still can't solve it or you have major impediments to solving it. You ideally want to keep all water out first and should concentrate all efforts outside the wall first.