Rotten joist

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Posted by: from Winnipeg
4/1/2012 at 2:25:40 PM

Taking apart the existing framing in my basement, I encountered quite a bit of mold. They didn't insulate properly or seal properly. And in Winnipeg, it is a must to seal a basement correctly.

But Upon pulling down a top plate, I noticed 2 of my floor joists are rotten. Not all the way through, but one is about 1/2 through and the second is only maybe an inch into the joist (2x10 joists). Being a bungalow, these joists sit into the concrete foundation.

My question is, how would I replace these joists without tearing up the flooring above, (it is completely finished flooring). Am I able to just support them somehow, without opening a can-of-worms? My house is built in '65 if it helps any.

rotten joist
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Date/Time4/1/2012 at 2:47:05 PM

You can replace them from underneath. If they are sitting on top of the foundation wall, then you remove any electrical and put in a new joist beside it that is the same length on an angle and hammer it in place. Screw it to the old joist, cut the holes and re-run the electrical. If the joists are in pockets in the foundation wall then they need to be removed completely. You can replace one at a time without much worry depending on how much weight they are supporting above.

There are a lot of different ways to handle this, if you can post pictures of the whole joist area, I could help out more.

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Date/Time6/3/2012 at 9:52:26 AM


First buy the picture that is shown, It looks like your studs are embedded into the concrete floor. If that's the case, then that's why the wood is rotten, not from an insulation Problem. Your bottom plate should always ride above the concrete floor. Also if that is the case, it should not affect the joists.

If the joists are rotten, it may be a cause of way too much moisture in the basement or, it's comming from the out side walls.

If its a painted stucco, that could be the lead of the problem. Cracks on a painted stucco could lead to this situation, and is very common. However The easiest way is to build a new frame inside the old joists, But you need to find the cause of the problem first.

You could remove joists, but you may case alot more damage, then you expect.nThe whole house sits on these joists.

To properly remove them, you would need to jack up areas of the house, That may cause you other problems, not just the flooring, You may cause water pipe seperating, or electrical wires to short.

Building a sister joist and fastening it to something solid Would be your best bet.


Winnipeg drywall and stucco

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