Adequate Joists?


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Old 12-15-11, 12:46 PM
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Adequate Joists?

I just moved into a house in Virginia. The house was built in 1982. Above most of the doors in the upstairs there are either cracks or places where the drywall is pushing out from obvious downward pressure from above. The joist in the attic are only about 6" deep (Im guessing - I have not measured). In Chicago my house had much deeper joists (maybe 16"?). The house inspector said the joists are standard. Also some of the door jambs are not plumb and the doors have problems with opening and closing.

Im wondering if the joists are adequate and is the joists the reason for the problems with the doors. And if so, what can I do? Can I bolt larger joists to the existing joists to improve the structural integrity?

As a side question - what can I do with the doors that are not level?

I would like to get it all sorted out before painting the rooms.
 
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Old 12-15-11, 03:33 PM
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1982 suggest that this house was built to some local code. Usual ceiling joists for a stick built frame is 2x6, for trusses is 2x4, so i suspect you are OK. How much insulation you have is another issue, which seems to be what you are measuring??? The minimum for most houses in the US now is about 12-14", or R38.
 
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Old 12-16-11, 05:19 AM
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I have enough insulation. Obvioudly I measured after moving the insulation out of the way.
I am not so much worried about what code dictated the minimum be, because, as we all know that is not always adequate and have a tendency to increase over time.

Let me re-phrase my questions:
1)What could be causing the pressure on the walls above the doors?
2)If it is the joists, could they be re-inforced be attaching additional joists to the existing joists?
 
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Old 12-16-11, 05:56 AM
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"You" are jumping to the conclusion that this is from downward pressure, or from some structural weakness. In all liklihood, that is not the case.

It is MORE likely that your house was built by a substandard contractor who just did a crummy job. Speed and quality don't usually go together. Headers that are not nailed adequately will move, and I would guess that could be the case if something is bowing outward, wood will naturally warp if it is not nailed down tight... Drywall that is not hung properly will crack if there is the slightest movement (you shouldn't put joints at the corners of doorways, it is just asking for a crack) so if the cracks are straight, and are at the corners of the casing, you can blame that one on the drywaller who did a poor job of hanging. Doors that are not installed plumb and level- or that are not shimmed sufficiently- will move.

IMO, you should remove the drywall at least 16" beyond the crack on each side, expose the framing, ensure it is nailed. Headers that are spreading apart can be screwed together using 3 5/8" ledger lock screws, countersunk slightly. The header also needs to be toenailed to the king stud on each end. Also glue the header to king connection with some PL, and then span that area with a new piece of sheetrock, moving the joint farther away from the problem area. As for the doors, they are pretty easy to fix. It might be as simple as putting some longer screws in the top hinge... or you might need to remove some casing and replumb and reshim the door.
 
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Old 12-16-11, 11:42 AM
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Good information - thanks!

I should provide more information on the "bulging" of the drywall. This has me most concerned. It is not bulging. But rather it is forming a crease in the paper at an angle of 45 moving from a corner of the door frame away and up the wall. So obviously the "cement" on the inside of the sheetrock is crumbling due to some form of pressure. Lemme see if I can "draw" it on the keyboard (the "/" is the crease);


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Old 12-16-11, 05:15 PM
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When drywall is cracked at an angle like that it usually means the king and trimmer are sinking, which usually means the whole wall is sagging. Think of it like this- everything above and left of the crack is basically staying put, while everything below the crack is moving downward... So weight may be an issue, but it is sagging BELOW the door, and doesn't necessarily mean there is a lot of weight ABOVE the door, although in multi-story houses, that weight is sometimes cumulative. The point at which the most concentrated pressure is on it is at the base of the king/trimmer at the bottom of your door, and this is likely the spot that is sinking and causing your doors to be misaligned.

Hard to say why this would be in your case, but what I have often seen is that if the wall is a non-load bearing wall, the wall is sometimes parallel to the floor joists, and if they did not put some blocking between joists, the wall is only sitting on plywood, which will sag between joists. In other cases, there is more load on the wall that what was anticipated and if it is on a single joist, it can cause that joist to bow. At any rate, since you are concerned with fixing the drywall, and probably aren't going to tear into the floor anytime soon, I think the advice I gave before would remain the same- tear out a larger area of drywall around the crack and do a repair as mentioned earlier. It will probably be good for another 30 years. Otherwise, start ripping up carpet and break out a long level to do some checking.

If you want to take some pics, you can upload them to a site like picasa or photobucket and then paste the link here.
 
 

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