So, I’m building a house for my brother. The area where he’s building has a high water table. When we had the hole dug for footings and foundation, no problems with the water. He has a 14′ x 14′ sunporch on the back of the house. What I’ve done in the past for post footings is dig a 4′ deep hole, build a 2 x 10 form 24″ x 24″, put some rebar in and pour a footing. (This is what the inspector wants to see).
However, when we dug the holes this time, we got down about 3′ and hit water. I’m stumped as to what I can do to get a good solid footing that is not going to move or sink. I thought of making a large footing and setting it in the hole, but I’m concerned that I’d just be sitting on soupy ground, and that eventually it would sink.
The problem is that the floor joists of the house run straight through out to the sunporch, so we can’t get much of the house built until we resolve this problem. Also, being in Michigan, we can’t wait til better weather (that would be May), and it doesn’t look like its going to dry up anytime soon (raining right now).
If anyone has had a similar experience, please let me know what you did. Thanks
Replies
Usual method is to install a manifold around the site with well tips every couple of feet. Manifold is hooked up to a large pump and the ground water pumped down below the level of excavation.
A coffer dam of some sort can also be built and the interior pumped down from a far smaller number of pump points. I have seen this done using sheets of plywood fixed in a trench and the trench, surrounding the location, pumped down. Used this to pour a 8' by 12' slab in a swamp.
On small sites I have seen a series of holes four or so feet deep and spaced at regular intervals around the spot your working. This can be used with blocking sections of dam if it helps.
This, depending on the ground water level and any rain, may have to continue during the entire process. Ideally this is done while the ground temperatures are well above freezing. Like June.
Michigan in late November and knee deep in water and mud? You were a very bad boy in a previous life. Do you have dreams of pillaging villages?
4Lorn-
Sometimes you are just so hilarious.
did your footer deeper and add a foot of 57 stone.
LOL. Got a little carried away with it. Glad you liked it.I lived close to a coast and ground water was inches below the surface. That's where I saw the manifold system used. Pretty elaborate and expensive but, as I understand it, cost effective on large areas as it eliminates the issue even in constant rain.The other methods are ones I have, in part or whole, used or seen used here in Florida near swamps or during the rainy season. Many years ago I was a laborer on a large site, two large and interconnected six-story buildings I made OT by staying all night in the rainy season and during two hurricanes manning the pumps with another guy. Trying to keep the water at bay so the crew of carpenters, about forty, would have someplace to work, park equipment or pour concrete come morning. I got trench foot and boots rotted off after the first week. We kept it up for a month. By then they were out of the mud and the worse of it passed.Dams, sumps, trenches, swinging chicken and Voodoo if it seemed reasonable, anything to get the water off site or keep it off.I realize his is a smaller problem but the principles hold.