Hey guys,
So I've got a crack in one of my floor joists in the basement. The joist looks like it's a pretty important one (it's a bit wider than the others). Right above the joist, on the first floor, there is also a column that seems to support the second floor above. So I'm gonna try and jack the joist up and sister some 2X10s on either side.
I don't want to remove the wiring that's going through the joist, so I'm planning to put some notches in the sister boards to fit over the wiring.
The crack has appeared where there is a notch in the joist for an air heating duct. The notch is actually fairly small- about a half inch deep by a foot across.
The reason I think the joist is cracking is because the previous owner of the house (or one of them- the place is over a century old) dealt with a slope in the first floor by pouring a concrete floor over the hardwood from the front of the house to the kitchen in the back. I think the concrete floor is about 2 inches at its thickest. Needless to say, I don't relish the thought of pulling up all that concrete (and honestly, I'm retiling the kitchen this fall and putting in new counters and cabinets, and the concrete does give a pretty flat surface to work on).
SO...
With all this in mind, my plan right now is to
0) Lay a strip of 1" thick plywood along the bottom of the joist, screws to fix it on one side of the crack. The strip will be about 3" wide- to fully cover the bottom of the two sister beams and the current joist
1) use a hydraulic jack and 6X6 post to jack up the joist and close the crack (the crack is very small right now- can't see to the other side, and only looks to have separated a few milimeters at the widest). I will use a short section of 6X6 runnign parallel to the joist, and on top of the 6X6 post, to try and distribute the force of the post pushing up (like a 6X6 T on top of the jack)
3) put a steel jack-post directly under the crack. On top of the jack post I intend to have two pieces of 1" thick plywood to help distribute the force; the piece of plywood directly on top of the jack post's top plate will be slightly wider than the top plate, and the piece of plywood on top of this will be a bit wider still. Kind of like a small, inverted pyramid.
- MY QUESTION HERE IS IF I NEED TO POUR A CONCRETE BASE FOR THE JACK POST- I'M Planning to leave it permanently in place. I read about pouring a concrete foundation with a re-bar X in the middle. If this is the most cautious thing to do, then I'll mix some concrete and pour a 2'X2' square down there with a couple of 33" rebar pieces crossed in the middle. I'm not sure how thick I should make the concrete base though. The floor of the basement looks like it's poured concrete.
4) After putting the jack post in place, I plan to then put a bunch of really strong wood glue on the two sister pieces, then clamp them togehter sandwiching the joist between them. Then I'll put some screws up through the plywood strip at the bottom into the joist and both sisters, and then I'll put some bolts through the sandwich. Two bolts at either end, then one kind of offset a little further down, and then maybe a couple more near the middle.
The sistering pieces I plan on making about 5' long.
SO, my plan is to leave the jack post in place permanently to give extra support, and also to have the joist sistered (while it's not cracking too bad, it is splitting a bit.)
I wanted to bring in photos but the camera died before I could copy them off of the camera and onto teh 'puter.
Cheers, and thanks for any suggestions
CS
So I've got a crack in one of my floor joists in the basement. The joist looks like it's a pretty important one (it's a bit wider than the others). Right above the joist, on the first floor, there is also a column that seems to support the second floor above. So I'm gonna try and jack the joist up and sister some 2X10s on either side.
I don't want to remove the wiring that's going through the joist, so I'm planning to put some notches in the sister boards to fit over the wiring.
The crack has appeared where there is a notch in the joist for an air heating duct. The notch is actually fairly small- about a half inch deep by a foot across.
The reason I think the joist is cracking is because the previous owner of the house (or one of them- the place is over a century old) dealt with a slope in the first floor by pouring a concrete floor over the hardwood from the front of the house to the kitchen in the back. I think the concrete floor is about 2 inches at its thickest. Needless to say, I don't relish the thought of pulling up all that concrete (and honestly, I'm retiling the kitchen this fall and putting in new counters and cabinets, and the concrete does give a pretty flat surface to work on).
SO...
With all this in mind, my plan right now is to
0) Lay a strip of 1" thick plywood along the bottom of the joist, screws to fix it on one side of the crack. The strip will be about 3" wide- to fully cover the bottom of the two sister beams and the current joist
1) use a hydraulic jack and 6X6 post to jack up the joist and close the crack (the crack is very small right now- can't see to the other side, and only looks to have separated a few milimeters at the widest). I will use a short section of 6X6 runnign parallel to the joist, and on top of the 6X6 post, to try and distribute the force of the post pushing up (like a 6X6 T on top of the jack)
3) put a steel jack-post directly under the crack. On top of the jack post I intend to have two pieces of 1" thick plywood to help distribute the force; the piece of plywood directly on top of the jack post's top plate will be slightly wider than the top plate, and the piece of plywood on top of this will be a bit wider still. Kind of like a small, inverted pyramid.
- MY QUESTION HERE IS IF I NEED TO POUR A CONCRETE BASE FOR THE JACK POST- I'M Planning to leave it permanently in place. I read about pouring a concrete foundation with a re-bar X in the middle. If this is the most cautious thing to do, then I'll mix some concrete and pour a 2'X2' square down there with a couple of 33" rebar pieces crossed in the middle. I'm not sure how thick I should make the concrete base though. The floor of the basement looks like it's poured concrete.
4) After putting the jack post in place, I plan to then put a bunch of really strong wood glue on the two sister pieces, then clamp them togehter sandwiching the joist between them. Then I'll put some screws up through the plywood strip at the bottom into the joist and both sisters, and then I'll put some bolts through the sandwich. Two bolts at either end, then one kind of offset a little further down, and then maybe a couple more near the middle.
The sistering pieces I plan on making about 5' long.
SO, my plan is to leave the jack post in place permanently to give extra support, and also to have the joist sistered (while it's not cracking too bad, it is splitting a bit.)
I wanted to bring in photos but the camera died before I could copy them off of the camera and onto teh 'puter.
Cheers, and thanks for any suggestions
CS