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1victorianfarmhouse 04-02-2012 09:42 PM

Patching Holes in Basement Floor
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I've two types of areas I want to patch in my basement floor.

The first are some shallow gouges about an inch or so deep. I've seen something that looks like JB Weld used in some warehouse floors.

The second is a bit more involved. There was an old load bearing support post in my basement, that rested on a couple of flat 2x6s placed below it. An additional layer of concrete was then poured, apparently when some drainage work was done.

I've noticed that the support post was loose, and upon inspection, it went into the concrete floor. Wiggling it around a bit, I was able to pull it out, and found rotted wood on the bottom of the post, and the rotted remains of the flat 2x6s inside.

My question on this one is what kind of concrete should I get at the home center to fill this void with? Once cured, I'll replace the post with a screw jack like is used elsewhere in the basement.



nealtw 04-02-2012 10:33 PM

I would just pick up a bag of ready mix for the hole in the floor and for the gouges use non shrink grout.

BridgeMan 04-06-2012 12:08 PM

Quikrete 5000 is a pre-packaged, quick setting product that would work well for the hole repair. Just make sure to remove as much (as in all) of the rotted wood out of the void first. And don't forget to tamp the bottom with a 2 x 4 or something similar to compact it, and wire-brushing any loose dirt off the sides of the void wouldn't hurt either. Follow the install instructions, and wait at least 4 days before applying heavy loads.

Speaking of loads, most steel pipe jack posts you mentioned are not intended for permanent installation, and the manufacturers aren't bashful about stating that on the product packaging. So do your homework before buying one for this location, getting the strongest possible. And also, use painted steel distribution plates (thicker the better, up to 1/2" or so) top and bottom instead of wood stock. The flimsy steel end plates on most jack posts will bend and deflect over time.

1victorianfarmhouse 04-06-2012 09:42 PM


Thank you for the very detailed and informative post. I was wondering what type of concrete, etc. I should get for the void, as I got different responses at two different stores. The void is clean, and is concrete on all sides and bottom. It was poured over the existing floor.

I was looking at steel pipe jack posts this week too. The ones I saw weren’t the beefiest, and I wanted to do some more looking. The other side of the stair way also has a support, and it too, goes into the concrete. This one comes about 2 inches shy of where it needs to be, and has a pipe jack on each side. The end plates on the top of the jacks is deforming, and I was thinking of getting the thickest ones I could to put between the jack plate and the rafter. I know a guy with a metal shop that should be able to make thicker plates.

But, this brings the question, if pipe jacks aren’t a permanent solution, should I be looking around for steel posts instead?



BridgeMan 04-07-2012 12:31 AM

You can certainly use custom-fabricated, steel pipe columns if you choose. Just make sure you give the metal shop the correct dimensions, because once they're out the door, they're yours. And be prepared to pay dearly for them.

If it were my own house, I'd prefer to use adjustable units, as they allow one to compensate for any future settlement that may occur because of footing movement, beam deterioration, etc. Thousands (maybe millions) of adjustable jack posts are in place that are made for temporary use only, and they are definitely better than nothing. However, I suspect the biggest problem with the majority of them is their inability to withstand any major lateral loads without buckling, with the potential for catastrophic failures. Smacking one of them while recklessly moving a refrigerator around the basement is definitely not recommended.

Do a google search for adjustable jack posts, and you'll find a number of manufacturers of units that are good for up to 40,000 lbs. or more.

P.S. I took another look at the picture of the rectangular opening in your earlier post--the bottom of that hole does not look "clean," but maybe we have different standards of cleanliness. I often used to tell our contractors that "if it's clean enough to eat off of, it's clean enough for new concrete to rest against--so just put your tongue on it to prove it."

inspectorD 04-07-2012 06:45 AM

Those temporary jack /adjustable posts are no good(and not code, but I won't use 4 letter words here:D). We call them Fireman killers. In a fire, the posts become spaggetti and fail , and under stressful loads, as stated by Bridgeman.
Any steel posts that are used need to be filled with solid concrete, this is why "lolly columns " are sold at the lumber yard. They will even cut to fit and you can weld plates that adjust to them.
Be safe,;)

nealtw 04-07-2012 12:02 PM

You could just install a saddle and use a 6x6 post.

joecaption 04-10-2012 08:39 AM

See if you guys agree, if there was just wood under that post that tells be it was a home owner fix to a sagging beam and there's no footing under that area to even support the beam. So what goods a beam going to do if it's just sitting on apx. 4" of concrete?

If there's any wood under that concrere it all has to go, it's only acting as a termite magnet.

nealtw 04-10-2012 09:37 AM

Joe: You may be right, I asumed with the post and 2x6 removed he was down to concrete. If not this post needs a footing.

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