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OldHouseGuy 12-03-2007 08:56 PM

How do I install a pier replacement?
Water damage on my 1920s house has caused total destruction of several cedar posts under my house. I want to replace them but cannot find a detailed explanation of how to do it anywhere!

I have an engineering degree and spent much of my youth working on a farm so I can usually do most mechanical tasks IF I have good instructions. I would rather preserve the historical nature of the house (as we have on almost everything else) and prefer not to use non-wooden posts but I am open to seeing other methods of repair, such as concrete.

Specifically, but not limited to, I need to know how deep to dig, what to put at the bottom to prevent sinking, jacking hints, how to put the post into the hole so that it is the right height, etc. Details, please! The house has moved in the past seven years no doubt partially because of the loss of support of water damaged posts. I have done what I can to prevent water from getting to the posts.

House info: 1225 sq. ft. single story located in San Antonio in Blackland prairie soil (black dirt and some clay) with 18-24" crawl space.


ToolGuy 12-04-2007 01:42 AM

Hi OldHouseGuy and welcome to the forums. Great username, by the way.

I'd go with concrete or steel. I'm all for preserving the historical integrity of an old house, but when the problem is under the house and could be a recurring problem, I'd go with a more practical method. I did a quick google search for "pier footings" and found something that looks appropriate. They're selling their own services but the photos and info seem pretty detailed.

ToolGuy 12-04-2007 01:57 AM

I wasn't going to act silly at first, but what the heck. I also found this during that same google search. :D

inspectorD 12-04-2007 07:21 AM

So is that steel..or concrete????:rolleyes:

Also Check with your local building official for any quirks they may like to see. I don't know if you are in a flood plain or hurricane you may need brackets or other hardware as an update to any repairs you make.
Let us know what they will help others.

Dress accordingly under the crawl space, and where a respirator.:)

OldHouseGuy 12-04-2007 08:10 AM

Thanks for the centex address, it is somewhat helpful. I see that a 2' pad is poured about 2' deep with rebar and that a tube is used to form the upperpart connected to the exposed rebar.

There is little room to work under my house and I would like to consider wooden posts instead; does anyone know how to lay a footing for this, how the post is inserted or angled in, and how settling is prevented? Are steel shims the norm for making up the apparently always existing gap, and where can I get them?

Extra question: I have some beams (some are 2 2x6s bolted together) that butt onto existing wooden posts that are either partially falling off or have destroyed the "edge" of the post so that they provide little support. I am considering, if I can gain 1/2 inch (maybe can't) placing steel plates under the butted beams to spread the weight across the entire top of the post and hang over the post to catch the over hanging edge of the beam. Thoughts on this, and where I might find flat steel plates and/or C shaped ones that will "surround" the beam?


glennjanie 12-04-2007 10:01 AM

Welcome Kirk:
It is possible to replace the wood posts, I would recommend using pressrue treated wood posts that are rated for ground contact. The depth to dig is to the 'hardpan', undisturbed earth. A piece of the post 2' long laid on its side in the bottom of the excavation would give more support. You are working for bearing per square inch. You should be jacking the house up to level for placing the posts; go 1/4 to 1/2" extra, measure the height and cut the post. For the top, allow an extra 1 1/2" and put a 2 X 6 X 12" on top of it paralell to the beam for a bearing plate.
Jacking can be done with a hydraulic jack (8tons) placed on a level spot on top of a 4 X 6 X 12" to spread the bearing. The hole being dug in a paralell fashion for another block in the bottom of it will give space for inserting the pier; then place the 2 X 6 on top of the pier and let the beam down on it.
You will need someone inside the house with a level on a 8' long 2 X 4 to let you know when it is level. You may have to put a jack on each side of the piers to keep one side of the beam from dropping. Do only one pier at a time and keep an eye on things, you don't want the whole thing comming down on you.
Please let us know how you come out.

OldHouseGuy 12-04-2007 04:30 PM

Thanks, Glenn! Those are EXACTLY the type of instructions I need. Putting the 2' section down under and angling stuff in makes sense to me. I found a junk steel place here that may have steel shims and/or plates for the jacks to keep them being driven into the ground, and I have to buy 10 1' sections of channel steel for the other problem I have (they won't sell less than that, $60). I may have some trouble at the corner of the house since there is a concrete base for a chain link fence in the way, but perhaps 12-18" coming into the center of the house will be enough of a footing, with the beam unfortunately sitting on one end of it.

Just FYI groan, I priced out the siding I need to replace (not including all of the stuccoing, etc.) and because what I have is bigger and bolder with an out of existence profile angle (and all of my 2x4s are ginormous and have to be purchased special, too) each 14' board comes out to about $100 for one full of knots and cracks in new fast growth yellow pine machined, or $300 per board for reclamed original long leaf pine cut to size. Jeez.....

glennjanie 12-04-2007 10:16 PM

Hey Kirk:
My house has California Redwood siding with 8" wide boards; I wanted to preserve the original appearance so I found 8" vinyl siding for it. It is a slow process considering my disability but it is comming along. I don't know what yours looks like but the vinyl might be a possibility for you.
Our house was built in 1956 and was probably the last house to be painted with lead based paint. No amount of preperation will make a new paint job last longer than a year because the lead keeps peeling off under the new.

OldHouseGuy 12-05-2007 09:13 AM


I hope that works for you. We actually work toward restoration not remodeling, so that we use as much as possible for 1920s or prior, so definitely no vinyl for sure. We have a 1929 fully operational phone in a phone shrine, original hardware including crystal doorknobs and redwood paneled doors with mortise locks and keys, 15' oak flooring, ironworked screen doors with ornate hinges, ornate brass and iron candlestick chandeliers and sconces, original window and door trim, double hung sash windows, wooden screens, etc.

The house was only owned by one family the entire 80 years so it was never remodeled or rented out, thankfully, and we are doing what we can to preserve the beauty of the home. But my dad and my pocketbook are the limiting factors, as I can't afford $300 a board siding and my dad, if he had his way, would Home Depot everything with fluorescent lights and plywood. It's an impoverished mind set, but I often need his help and argue with him constantly about his lack of vision and stewardship.

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