I live down on the coast and my house is on pilings (12), We are in the early stages of enlarging the house 1800 sq ft, or 8 additional pilings. While in the process of planning the addition the engineer pointed out that several of the existing pilings are rotting out just below the concrete cap and need to be replaced. One of the worst is in the center of the house. Replacing pilings with new wood seems to be a pretty straight forward process, but there is a lot of concrete patching. I can just replace the ones that need it now but feel I’ll just be chasing my tail as far as concrete work because I’m sure, though they don’t show damage now, all the pilings will eventually have the same issue. The engineer thinks I should go back with concrete pilings where needed but I don’t like the idea of split wood and concrete for resale problems. I want all of one or the other. The engineer says concrete pilings can be done one piling at a time without raising the house; I don’t think it can be done correctly without raising it. I think to give me a strong foundation the house needs to be raised but have no idea what raising a house and having it sitting around while all this foundation work is being done would cost.
I think a benefit of raising would be that I could raise the house another foot for flood insurance reasons and also, rotate the house about 5 degrees to eliminate an encroachment of one coroner of the house over the build line.
What do you think about the five approaches.
1 replace the ones that are bad with wood and each of the others as their time comes due. (about $1500 per)
2. replace the ones that are bad with concrete and each of the others as their time comes due. (about $200 per)
3. replace all with new wood (about $1800) plus slab
3. replace all with concrete. (about $2400) plus slab
4. Raise and rotate the house; replace all with concrete, taking care for the encroachment issue and hopefully lowering flood insurance rates. (I haven’t a clue)
Tom: First off, I don’t think the engineer knows that you don’t have to raise a house to replace a …
Charlie: No, no, the engineer said you don’t have to raise the house. He wants to raise the house-
Tom: No, no, he said, according to that question, you don’t have to raise the house if you use concrete piers. You don’t have to raise the house if you use wooden piers.
Charlie: Oh, I didn’t … okay.
Tom: I had seven of them replaced in my own home many years ago, when I did own a home in Galveston. What happens is you’ll have to chip the concrete around the pier you want to replace, and then you water-inject into the sand. You actually stick those pilings way down, put them in place, push them up against the house. They shore them, and then the sand dries out. It’s a suction that keeps that piling in place. For every foot up, you go a foot down.
If you just want to replace the rotten ones with the new .6 pressure-treated, that would be the best way to go and the cheapest way to go. If you already have insurance, there’s no reason for you to raise the house, unless they’re telling you you have to to get insurance. If you want to do that, that literally means you’d have to get cranes out there to lift the house up. Then if the whole house is lifted, you might as well just put new wooden ones in. It’s not a big deal.
As far as most cases down there, you just replace the rotten ones, the wooden ones. They’re very simple to replace. I think I paid 550 bucks a pier when I did it.
Charlie: That’s a while back.
Tom: Yeah, it’s probably more like 1,000 now. That was 10, plus 10 years ago.
Charlie: They came by horse.
Tom: I don’t think, if you have a house down there and you have insurance, there’s no reason to raise it.