Latest Discussions : Basement & Foundation

11:44AM | 06/04/03

Member Since: 06/03/03
2 lifetime posts

Replacing Basement Support Posts

I'm replacing 6 by 6 wooden support posts in the basement of my 95 year old home. The 3 posts were sitting on concrete piers which are 3.5 inches below the concrete floor (the rest of the floor). When made, the original basement floor was dirt with three concrete piers for the support posts. The entire floor was cemented over later, around the posts. The wooden posts are now rotting and the main beam sagging. One of the three piers was built up above floor level at some time in the past with concrete. The other two posts are sitting on piers which are still 3.5 inches below the rest of the floor. I have already replaced the post on the raised pier.

Regarding the other two piers that are still 3.5 inches below the rest of the floor. I don't think I can set my new steel post in the hole because the adjusting bolt will be out of reach of a wrench. I expect I will have to pour in concrete to fill the hole, then set the post on that. Three questions:

1. Any special type of concrete?
2. How long to let the concrete cure before setting the post on it?
3. Should I fill the concrete level with the floor, or raise it a little like what was done to the third pier that I have? Not sure of the advantages. Perhaps it helps not to crack the surrounding floor?

Thanks for any suggestions! I can probably ask the folks at Home Depot about #1 and #2, but I'm clueless on #3.

Mike

treebeard

01:58AM | 06/05/03

Member Since: 01/14/03
262 lifetime posts

Adjusting bolt? Are you replacing the wood posts with lalley columns?

Assuming that you've jacked the house up to get rid of the sag, and you've constructed temporary supports so you can remove the wood posts, all you really need to do is install new lalley columns in their place. Set the base plate right on the existing concrete pier (if it's still in good shape), set the lalley column on it with the top plate between the column and the beam, nail the top plate into place once the column is plumb, and set the load back down on the column. When both columns are in place, re-pour the floor around them. The concrete floor poured up against the column base will keep it in place.

miketherehabber

08:52AM | 06/05/03

Member Since: 06/03/03
2 lifetime posts

Thanks for your input!

I won't be using a lally column, which I now understand is concrete filled. I'll be getting hollow steel support posts from a local supplier. They make two kinds, "schedule 40" and "scheudule 11" (referring to BOCA which I'm not an expert on), with the schedule 40 being significantly stronger. Each is "permanent", but has 3 inches of play built in via an adjustable bolt at the bottom. I like your idea about setting the post in the hole and filling it with concrete. I'm just not sure I'd be able to reach the bolt with a cresent wrench to tighten it and raise the top plate against the main beam with the post already standing in that small 6" by 6" hole. In order to get the post in the hole, it can't be fully extended. I can only adjust it up the final inch or two after it is sitting vertically in the hole. Then, the hole is only 6" by 6" so I wouldn't be able to get the wrench around the bolt. That is why I'm playing with the idea of filling the 6 by 6 hold with concrete first, letting it cure and then setting the new post on that. However, I like your idea about cementing it in. That would provide much greater stability. I have a lot to think about!

Thanks again!

Mike

treebeard

09:40AM | 06/05/03

Member Since: 01/14/03
262 lifetime posts

Have to admit that I've only run into one renovation project where the supporting columns were empty steel or iron pipe...with bottom plates only...no top plate...duh... I didn't like that arrrangement and it was done away with PDQ. The idea of empty pipe by itself is a little troublesome to me, also. But that's just my opinion. Others will say differently. The addition of a concrete fill within the steel pipe offers both increased stiffness and increased bearing surface for the loads set upon the column, which can be significant.

The idea of the whole thing being an adjustable column support requiring a crescent wrench to tighten it is also just a little troubling. How does on insure that the column has been raised to maximum bearing on the beam above? Well, like I said, that's only my experience...lacking any with these type of supports you describe. The closest I've come is the pipe jacks used for temporary support when lifting a structure or beam (like yours) in order to construct additional temporary stud partitions while installing new lally columns. The jacks afford the opportunity to actually "lift" the structure to a position just a little higher than the final position so that after the lallies are in place, the load can be lowered to it's final resting position, rather than lifted into it. I find that to be a more comfortable fit, especially when dealing with a sagging beam that needs to be brought back into original position in order to save the structure.

Anyway, good luck.

BV004265

12:41PM | 05/11/14

My house was built in 1927 and my parents bought it in 1947 well I own it now and about a month ago I noticed alot of rust at the bottom of the metal round support beam. Well I touched it and it just fell over .I had to lay it down on something in my basement. Where do I buy a new metal round support beam?

BV009056

12:22AM | 09/27/15

I am preparing to replace steel support posts in my basement and the columns you are describing are what I am looking at using. Building code requires the screw to be at the bottom bellow the finished floor so when it is finished, the concrete floor locks the adjusting screw in position making it a permanent support column. I suggest speaking with your local building inspector, Better safe than sorry when it comes to supporting your house.You may simply have to cut the hole in the floor bigger to allow room for adjustment!

BV018093

10:40PM | 11/29/18

I would raise the supported beam enough to allow hand tightening the adjustment nut on the bottom of the pole, then when you lower the horizontal support beam to the desired height the pole would be tight. Then you fill the hole with concrete and that should lock the nut and pole in place. The beam would only need raised about 1/16" to 1/8" above level to allow placement and adjustment of brace pole.