Question on jacking up a corner of garage

[plain garage]

Our house is built on a slight hill with an attached garage with a bedroom right above. The left front corner of the garage happens to be the lowest point of the of the house. Over its life (50+ years) that corner has settled roughly 2 to 3 inches thats noticeable when walking in the room above. Its built on a short stem wall with double sill plates and 16 oc studs above.

The sill plates towards that corner appear rotted but not visibly compressed. Im planning to raise the floor joints of the bedroom and stuff some hardwood or rocks underneath the sills, is that a good idea?

Also, due to the corner location, i need to use a bottle jack, will a 12 ton be enough? I have some screw type lolly columns to hold the joists once they are raised.

 

[Kaizen]

Yes 12 will be enough. You will need some half inch steel for between the jack and wood and some 6x6 to spread the jack point to several floor joists.
If there is any foundation to sill bolts undo those. Fix it right. Get new sills to put in and some concrete to fix any foundation issue you find.
While this is basic work it is very dangerous. I have seen someone using a 2x6 have it snap and one piece go right through the wall. So use some steel, then jack, then steel, 6x6, a cross piece of 6x6 under joists


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[matt_i]

Im planning to raise the floor joints of the bedroom and stuff some hardwood or rocks underneath the sills, is that a good idea?

That would not be my first choice. Treated 2x lumber first for the new bottom plate followed by whatever stud length needs to be sistered to make up the new height (all the way up to the top plate as in full-length new stud). I would use some steel reinforcing clips like a Simpson A23 angle plus their "strong drive" screws to beef up the connection.

 

[L5wolvesf]

I had to jack the corner of our house, long story why, which was an add on and only about 10 years old. Got it done pretty easily but didn't think about what else had been done wrong. It was "square" with the slope and when leveled the door didn't close well and the interior panels, which we had removed (for insulation) didn't fit right when reattaching them. Luckily it is only a store room.

 

[Cyberbear]

Take your time, plan things well and consider the long term results of all that you do.

 

[e36jon]

I'll add that doing the 'raise' and 'lower' slowly will minimize the damage to interior finishes in the interior above. The lally-style jacks I used recommended a 1/8th turn per day, which I ignored and cracked the drywall joints all to heck upstairs...

 

[Kaizen]

I'll add that doing the 'raise' and 'lower' slowly will minimize the damage to interior finishes in the interior above. The lally-style jacks I used recommended a 1/8th turn per day, which I ignored and cracked the drywall joints all to heck upstairs...

Heh heh I jacked a fifteen foot side of my 100 year old colonial to fix the sill. For two weeks I gave the bottle jacks half a pump a night. All night you could hear the ole ***** groaning and creaking. One night something snapped loud enough to wake everyone. Never did find what that was


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[Kevin54]

Instead of using a bottle jack, I would borrow a house jack that you know will raise it. I don't think a 12 ton bottle jack will work actually. And then you might have bleed off on the jack. A house jack will insure that you raise things up, plus it won't bleed off. Give it a turn every now and then, and you'll be set.

 

[plain garage]

I have 2 lally columns with screws/house jacks, but the handle needs 180 degree clearance to turn. The corner of the garage only has 90 defree clearance, thats why i wanted to use a bottle jack under the outter most joist. Planning to use a torin 12 ton. I will put the lally columns under the adjuscent joists to spread the load. The plan is with every pump of the bottle jack, i will snug up the screw jacks. I will try to go 1/2 inch per week, and replace the sills with PT lumber.

Where do people get 1/2" steel plates? Went to HD didnt see anything there. I will lay a piece of 2×10 on the floor, then jack then steel plate, then 6x6 then 4x6 across 3 joists supprted by other lally columns.

 

[matt_i]

Where do people get 1/2" steel plates?

Couple of options, local welding/fab shop/machine shop may have some drops, order online thru various online metal suppliers, possibly a scrapyard which has heavy steel and not just junked cars, some places like Metal Supermarkets have retail locations.

 

[Kaizen]

I just went to my local metal seller and got my plates for twenty bucks. 6x6 is fine. I tried the Lally column plates and they folded like a fan.


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