We’ve put an offer in on a house that’s built on pilings. There is maybe a 2-3 foot gap between the ground and the first floor of the house. When our house inspector was there it was the day after a heavy rain and there was standing water under the house. He says the lot needs to be regraded or something has to be done to stop the water from collecting under the house. He said it would, for one, increase our AC bill a lot. We’re still in negotation over some other things he found, so any input on this situation would be appreciated.

The inspector is absolutely right. In fact, something needs to be done to stop the water from getting under the house. My suggestion is, go about 3 feet out from the house and install a french drain. Then, put a short concrete wall under the edge of the house. If the piers are made of wood, you will have a termite problem. Yes, termites eat ALL wood, some faster than others.

The correct terminology is “pier and post”, and they carry the weight of the floor joists at or below span. There are generally two types of perimeter foundations associated with this type of construction. A continuous stem wall around and under the exterior of the dwelling, often, but not necessarily interrupted by an 18″sq. under-floor access, surrounded by a concrete curb, 3″ above the adjacent grade. The second is a curb foundation with a cripple wall supporting the exterior of the building. If you have the latter, a flash-wall, at the exterior, correctly doweled and reinforced ti a height of 6″ above the final finished grade level, in addition to the grading would be an imperative. With a stem wall and the correct grading and directing of the water flow should
be all that’s necessary. Having sad all that, how is the water table in your area, because that is an entirely different solution.

In my area (Texas), we call it “pier and beam”. I like this type of construction over a slab house because you can redo plumbing as needed. Water is common, but not good. Moisture causes mildew and rot. No wood should touch the earth.

My husband said the pier and post isn’t what we have — we basically have telephone poles (very long ones) pounded into the ground and the joists set on the pilings. There is no cement at all — we’re in a sandy area near the Atlantic ocean so the water table is quite high — about 2 ft down at best. That said, it sounds unanimous that the water isn’t good, so we know not to pay attention to the second opinion that they’re getting if it disagrees with what we are pretty sure about. Thanks for all the input!

Indeed, when “piles” are driven to refusal then cut. Your house sits on piling, not post, not piers, but piles. Very common method along coastal areas. About the best way to insure that water does not stand under it is to fill in under it. Not the easiest way when it sits as low as yours does though.