# Jacking up sagging floors.



## JB617 (Oct 29, 2008)

I recently bought an investment property that needs structural work. The floors sag from the outside walls to the center. I have had a structural Eng out to the site and am awaiting the report/plan. My question is whether or not I should wait to get the structure fixed/floors leveled before i replace the roof? I am on the clock here as I have less than a month to strip/replace the roof to satisfy my insurance company. i guess the bottom line is, can I replace the roof now and jack up the house later without damaging the new roof?

Thanks in advance for any advice..


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## Shamus (Apr 27, 2008)

Just Me but I would not waste the time, trouble and cost to do a roof and then have to redo after the floors are leveled.

Go to your insurance Co and explain the issue. They will work with you as it is in their best interest to do just that.


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## 47_47 (Sep 11, 2007)

Shamus said:


> Just Me but I would not waste the time, trouble and cost to do a roof and then have to redo after the floors are leveled.
> 
> Go to your insurance Co and explain the issue. They will work with you as it is in their best interest to do just that.


x 2 :yes:


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## Marvin Gardens (Sep 30, 2008)

Floors first, then roof.


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## o_jay66 (Oct 17, 2008)

Actually, you might want to do them at the same time. Depending on how/where it's sagging, taking some load off of the roof (i.e., stripping off shingles) might make it easier to raise any floors under load-bearing walls. This might take some scheduling acrobatics. The benefit might not be much, but I don't think there's much risk in replacing the roof first either, unless the floor is sagging so bad that pushing it up under a load-bearing wall would open a roof joint or something. If you bring up sagging floors to your insurance company you might draw attention you don't want.


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## Maintenance 6 (Feb 26, 2008)

It mostly depends on how much sag and where it's at. How are you addressing the sag?


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## JB617 (Oct 29, 2008)

Thanks for all of the replies. Appreciate it. The sag is right down the center of the house dropping noticeably at least 2 inches from each outside wall to the center. The sag runs parallel to the way the floor joists are run from the front to the rear of the house. In other words, you walk in the front door and look to the back of the house and right down the middle, the house is sagging into a V shape.

The roof (which is a hip in design)does have 2 layers of asphalt shigles and a wood shake drip edge. Lot's of weight on it.


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## Marvin Gardens (Sep 30, 2008)

JB617 said:


> Thanks for all of the replies. Appreciate it. The sag is right down the center of the house dropping noticeably at least 2 inches from each outside wall to the center. The sag runs parallel to the way the floor joists are run from the front to the rear of the house. In other words, you walk in the front door and look to the back of the house and right down the middle, the house is sagging into a V shape.
> 
> The roof (which is a hip in design)does have 2 layers of asphalt shigles and a wood shake drip edge. Lot's of weight on it.


Keep in mind that the weight of the roof is on the bearing walls and not the floor. The floor is a separate issue and doesn't have much affect on the roof,

unless,

The bearing wall supports are sagging also, then you need to do some serious jacking.

The bottom line here is that you have some structural problems that need to be corrected first. If the roof is affected I would go with fixing the structure first, then the roof.

The reason for this is that if the roof has sway back once you jack the house up it could cause more problems as the roof struggles back to normal. With all the new nails in it they will have to adjust and will fight to stay where they are. Currently the old nails used to be in the right position and will go back there a lot easier.

The second consideration is that if you tear off the roof, then do the structure, then do the roof, you will have to do it very fast as this is winter and there will be lots of condensation. So unless you are prepared to do it all at once and do it real fast then fix the floor first and then the roof.

Of course I am not there to look at the situation but all the homes I have jacked up over the years, this is how I have done it and it was for the reasons stated above.


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## Maintenance 6 (Feb 26, 2008)

I'd have to agree with Marvin. Level the structure first, then go after the roof. You said it is a hip roof, so there should be no structural supports under the ridge bearing on the center of the structure. That said, you should be able to roof first, but you still could get some shifting and resettling when you go to jacking the floors back into place. Your description sounds like some posts under the main beam have settled. When you go jacking this back up you need to go slow and steady. It didn't settle in a day or two. Don't expect to jack it up all at once.


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## Marvin Gardens (Sep 30, 2008)

Maintenance 6 said:


> When you go jacking this back up you need to go slow and steady. It didn't settle in a day or two. Don't expect to jack it up all at once.


Also you will have to sister in some more joists.

When joists settle like this it pulls the cellulose fibers away from each other and they will never return. This means they will easily return to the position they are in now. The strength they once had is now gone.

I am sure the engineer will give you a plan of attack. You could do it all yourself as the solution is simple in principle but difficult in execution.

Jack up the sagging joists. Put in more supports so there is less span. Then redo the roof.

That was easy and I am not even tired.


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## JB617 (Oct 29, 2008)

Thanks everyone...Appreciate the feedback..


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## Shamus (Apr 27, 2008)

You don't give us the age of the house. If it's a turn of the century version, 2 story with a hip roof then you most likely have a center beam that the joists are let into in the basement. A 2 inch sag is a lot to move if it's 2 story.

You don't want to bring up a 2 story quickly, not much plaster will survive.
But I'm guessing here. Most hip roofs are built on the foursquare design and with that much sag I'd say that's what you have.

Am I close?


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## super carpenter Rob (Oct 28, 2008)

what is the spand of the floor joist they may be to long and may need a center support beam if they are not to long and just sagging you can jack up where the sagg is and ad anohter joist what you do is jack the sagging joist then ad the new joist crowned and nail every 12" 3 nail you can also so through bolt them every 2 feet regards Rob


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## JB617 (Oct 29, 2008)

Hello Seamus and Rob,
The house was built in 1930. It is story and a half? The second story is actually 2 long and narrow bedrooms due to hip roof design, I think it is considered a Bungalow. At each end of the roof there is a dormer.
The dimensions of the house are 28' wide and 50' long. There is no center stick in the basement. The floor joists(2x6) run length wise with 4 12"x12" beams supporting them in between the two outer sills. Therefore the joists span 10' between beams.
I am not worried about plaster as I have gutted the house already in order to insulate, rewire and plumb. All old knob and tube wiring and zero insulation.


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## Marvin Gardens (Sep 30, 2008)

If they are 16 inch centers then a 10 foot span is just over the maximum limits of being the correct size dependent on live weight. A 2x8 would have been the correct choice.

If they are 24 inch centers then it is way outside the span maximum no matter what you have for live weight.


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## Maintenance 6 (Feb 26, 2008)

Since you have a 1-1/2 story with finished rooms on the second floor, I'm going to assume that you have knee walls connecting the floor joists to the rafters. My guess is you should be able to see some separation somewhere in the framing on those walls since the floor sagged, unless the rafters sagged along with them. At any rate that is all the more reason to level up the structure before reroofing. And all the more reason to jack this thing up VERY slowly so things have a chance to settle without tearing joints apart. I would bet that the knee walls are going to want to push up on the rafters as you jack things up.


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