DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Building & Construction (
-   -   How to replace wood support posts under main beam (

webjanet 09-07-2008 10:03 PM

How to replace wood support posts under main beam
We bought a 120 year old frame two-flat in Chicago. We got the property about 75% rehabbed and are finishing it up - along with replacing a lot of plumbing that burst last winter.

This is a standard Chicago frame 2-flat and in the basement there are three 6x6 wooden posts holding up the main center beam of the house.

The house is 20 feet wide and about 32 feet long.

Here is my question:

My husband and his friends want to REPLACE the 6x6 wooden posts with metal support poles they are buying at Home Depot.

They are telling me that they can use temporary jacks on each side of the current posts to hold up the center beam, then cut out the old wooden posts, and then install the new metal posts, and then remove the temporary jacks, essentially 'lowering' the beam back down onto these new metal posts.

I am of the opinion that nothing seems to be wrong with the posts so why mess with them. My husband points to the bottom of one of them where it appears to be 'thinner' and he says that part of it has 'rotted' near the floor. I think the cement there looks uneven under the existing post and they would also need to replace the cement and let it cure, etc. first.

Of course they think since I'm a woman -- what do i know? Personally I think we need to call an actual engineer to come in and look but the guys all insist this is pretty easy to do and commonly done and that they can do it as described above.

His friend says you install the jacks on each side of the posts and 'crank them up' a little every day for a week, then replace the post, then 'crank the jacks back down' a little every day for a week and you are done.

Am I crazy or does this sound like something that shouldn't be done?

Termite 09-07-2008 10:15 PM

You're somewhat right.

As long as your husband is installing a solid footing for the beam posts (or determining that there is an adequate footing), he's doing right. An adequate footing depends on the load on that specific post. Around here, an average beam post is 12" thick and 36"x36", reinforced with a rebar grid.

I would be concerned about them wanting to actually jack the house up. That is something that should be left to professionals. Most columns have threaded bottoms on them that allow them to be cranked tight. My suggestion would be to rigidly support the beam with temporary supports tightly shimmed in place. No need to raise the house at all. When the footings are poured and cured for at least a couple weeks, the columns can be installed and cranked very, very tight. Then the supports can be removed. No big deal.

My suggestion would be to do one or two at a time, not all in one weekend. That way your entire house isn't on temporary supports that only bear on your basement slab, which isn't capable of taking all that weight itself.

I think your husband is right to replace the posts if they show any signs of water damage, rot, wear, or other damage. If they're in good shape, why mess with them?

All times are GMT -5. The time now is 09:19 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1