Corner of house sinking - how to put up posts in basement?

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Old 07-20-11, 09:07 AM
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Corner of house sinking - how to put up posts in basement?

We have a house built in the 1870's and the southeast corner has been slowly, now quickly sinking! There are cracks in the plaster upstairs and the floor below it is very uneven. I suggested jack posts for now, and some sill (and probably joist) repair. My husband is worried that these are too lightweight, given the size of our house (3100 sq. ft.) and the fact that he once saw one of these "sink" into a concrete floor (?!) like the one we have, though ours appears to be in good shape.

Any suggestions, before the thing caves in?
 
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Old 07-20-11, 09:24 AM
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The whole house is sinking or just the level above ground?

Sill and joist repair? So you know why the sinking is happening?

Can you provide some pictures?
http://www.doityourself.com/forum/el...your-post.html
 
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Old 07-20-11, 10:05 AM
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Sinking house

Thanks mitch - as far as we know, the problem is not with the basement, but the sill. We know there is old termite damage, but a mason who re-pointed the brick on the outer basement recently told us that the sill needs replacing. There is probably new termite infestation and/or carpenter ants as well. Ugh.

This happened on the other side of the house, and was repaired about 5 yrs. ago. We didn't know then that 4 of the joists were also severely damaged. In fact, two had split where the tenon met the foundation and they were sistered and reattached with brackets. This is probably what's going on on the other side, but the floor is merely sagging, not actually bouncing (!) like the other side was.

I have a Photobucket acct. but haven't taken any pics of that side of the basement yet. Time to do it!
 
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Old 07-20-11, 11:12 AM
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First, get the house inspected and termite treated. There is no reason fixing if the cause has not been dealt with. And also look for water leaks that also may be causing rotting and contributing to the pest problem.

So you have tried installing a lally column already and it broke through your concrete floor or did he see that happen on another house?

The overall size of your house is not important when considering columns. What you are trying to support with the column is important. How much house is above the area you want to jack up and support with lally columns?

Yes, lally columns can be used as temporary and as permanent support but it all depends on your building. A column should be installed on a footer. If you are putting a column where there was previously no column there is probably no footer existing so cracking the floor or breaking through is a possibility (remote, but possible). If you just need something temporarily more columns can be installed to spread the weight out so you don't create such a point load on the concrete floor.
 
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Old 07-20-11, 12:05 PM
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Sounds like work!

The column that sank thru the basement floor was in another house. We've had many on the other side of the house, while the sill was being repaired and a couple were left there.

Good point about the footing. I asked my husband if there was anything distributing the weight (of the house) he was in (a job site--he's a carpenter) and he said no. They had other subs working on it so he probably didn't feel comfortable critiquing them.

I remember my dad using lally columns and always pouring a footing.

And yes, we need to get that sill treated for termites, and probably the whole house. At least there isn't a moisture problem...I THINK!

Great reply - thanks!
 
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Old 07-20-11, 06:37 PM
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Put the jack posts on top of 2x12's to spread the weight out on the floor. The strength of the floor has a lot to do with the quality and thickness of the concrete. You have an old house, so chances are it's quite thin. They use 2x material under scaffolding posts in NYC. I'm sure it will work well for your temporary bracing. The more posts you use, the less weight there is in one spot as well.
 
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Old 07-20-11, 08:29 PM
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You are looking at raising a portion of the hose for leveling, replacing a sill (if necessary) and possible adding and extra permanent column. This all costs money and it should be done right or the problems will be magnified in the future.

You need a professional inspection (not just a carpenter, remodeler ot a builder looking for work. Once you had some actually look at the situation and take some measurement or shoot some levels to see the magnitude, you be able to make a good decision. If you can get a structura/civil engineer out to look at it you will get an indedepeant opion of the problem and possible repair options. A professional is just there to give you information and makes no money on the repairs, but he might be able to give you a few options on people or types of contractors. The cost will not be more than repairing cracks in additional rooms properly.

There also the option of listening to the good old boys that have not seen it or are looking for an additional job.

Dick
 
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