bad slope on our floor

Without details this is just a wag. Bad says to to me that at least a 2x6 is required so as to have enough screw /nail points for a secure installation.


The next unknown is how far out in the other direction.


Laser levels are nice when calibrated. Sometimes in old house marbles and eyeballs combined with single level is entirely accurate.

 

Sometimes better to level the house and not just the floor,
Canada is a big neighbourhood, can we get a little close.


Basement or crawlspace and what repairs are being done?

 

Probably need to get that foundation work done prior to working on individual floors.
Hard to tell without a site evaluation. Not much sense trying to level a floor if foundation work is going to move it.

 

Yes, the foundation work is being done first!
They are just stabilizing though not jacking and lifting the house. The sinking was near the middle of the house not the outside walls. Here is a pic showing a 1-2" curved slope but the floors also angle down maybe 3-4" at the worst point 24' in from the outside wall to the middle. The angle is both longitudinal and lateral so my thinking a laser would help? Current joists are 3x10" real not lumber size.

Is the 3rd floor of a 3 floor townhouse, each separate apartments (building owner)

 

Yes, the foundation work is being done first!
They are just stabilizing though not jacking and lifting the house. The sinking was near the middle of the house not the outside walls. Here is a pic showing a 1-2" curved slope but the floors also angle down maybe 3-4" at the worst point 24' in from the outside wall to the middle. The angle is both longitudinal and lateral so my thinking a laser would help? Current joists are 3x10" real not lumber size.

I would like to ask more questions the lifting it direction unless you think that is right out of the question. Even if we just talk about it, you can always decide no.

 

I don't see a pic, but 4" of settling in the center of a house is sever. Might be time to hire a structural eng. to help develop a plan. Safely!

 

I

A structural engineer has seen it and planned.
Now..... the floor please :surprise:


If was caused by plumbers digging a trench in the middle of foundation earth for pipes and not back filling. Or at least that made the problem far worse. That plus a rotted joist.

 

What type of attaching would be best, glue then structural screws, lag bolts or nails?
Do I need to do full length sistering or just in certain areas?
How do I make sure that it is flat both longitudinally and laterally?
I saw a video where someone makes a 5ft level mark on the wall but didn't understand how that would help leveling the floor lower down. I thought a laser could just be put across the floor aimed 2 or 3 ways - any recommendations for lasers? I assume a string across the room would sag a bit in the middle?

 

What sort of foundation do you need to raise the house? The foundation companies, and we've had 3 quotes didn't even consider this. All said stabilization only. The other issue I think is that each floor has a different slope problem mainly because they have been redone at different stages. I think the ground floor was leveled in the past but then sank further. At least we see a bigger problem on the 3rd floor than on the second than on the 1st. They want to put 9 pilings in. 4 along front and the other 5 along the main load bearing beams down the middle.

 

Also it's not a detached house, we have neighbours with party walls.

 

Don't know about Canada, but here in the US we have laws/regulations concerning party walls. I would strongly suggest you research your area.

 

Up here, if it old it is what it is, but new would have a common foundation and 2 walls one inch apart with drywall in the crawl space and attic the only time they touch each other it the roof sheeting and facia.

 

Right, so, back to the OP. How do I level the joists without jacking?
We have an engineer, we have plans, we have a permit, we own the building.
I am doing my research on that at the moment whilst waiting.

 

You need a laser that is self leveling and will give you a broad line. So you set it in a window and you can measure down from the line anywhere in a room.
https://www.bing.com/videos/search?...=Lazer+level&view=detail&mid=5C859859501B29D6BE4F5C859859501B29D6BE4F&FORM=VIRE

 

A laser level mounted on a swiveling tripod where the laser is level. Then you have to determine the inches of deviation in all directions.



Then you have to pick a starting point and without seeing the various deviations no one can answer where that starting point may be. Once the probably highest joist is as level as possible everything else is leveled to it.

 

I agree with above, shoot level laser marks all around the room, especially the 4 corners. Doesn't matter what height. Once you determine the new floor height measure from there to the level marks. Now you have a base line to work from.


To sister joists, attach them first with a few 3" deck screws. Once you establish that it is in the right spot nail it in place using 3" framing nails at 3 or 4 every 12" or so.

 

Any reason nails better than screws?

 

Screws will work if you use lots more, they don't have the same sheer strength as a nail.

 

Ditto what Neal said. Screws are heat treated and brittle, they often will break in lieu of bending like a nail, and inspectors don't like to see them in place of framing nails.


I would just use a few to set the height of the new sistered joist. If you want to adjust, screws are easier to back out then pulling nails.

 

Sounds like bearing walls have been taken out.

 

How much of the 2x6 or 2x8 needs to be below the top of the joist? At least 50% or could I get away with a bit less?

 

I would think 3" would be good but I have never done anything like that, usually a 2x4 to raise the level 1/2" or so.

 

Did something similar once or twice. I prefer 4" of overlap to allow 2 nails one over the other. All the sisters need not be the same size so you might be able to save a few bucks on lumber.