I am currently in the rocess of totally remodeling my 1905 farmhouse. My question is about sistering new 2×10 joists to the old 2×8’s. The span is 15′ and the existing 2x8s sag almost 1 1/2″.
Question: When I double up with my 2×10 should I lift the sag out of the 2x8s and nail the bottoms flush, or will this cause my 2×10 to sag a little as well? I am not planning on finishing the basement ceiling so its no big deal to deep them sagged and nail rightt to them. Just looking for advice from someone who may have done this before, thanks.
Matt
Replies
I'd be jacking them up first. Since the 2x10 will protrude to the bottom side, you would need several jacks and posts, one for each. This will take time, You might only get an inch the first day, then another quarter inch the next day, then an eigth...
Once they are up, siste with plenty of nails and const adhesive ( PL Premium) and leacve the jacks in for another few days. That lets the opld joists learn to like their new home.
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You actually would not need several jacks. I was thinking that way because I have about twenty of them...
But you can do it with just one. Jack the joist straight in themiddle of the span, then cut a tight fit 2x4 leg to fit in on either side of it, let the jack out. Problem is you would be fighting with the joist one either sied of the one you are working on, so there could eb a lto of leapfrogging, the more jacks, the better, but you can do it with only one if need be.
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Good idea. Ill leave the jack in for a couple days, hopefully they wont sag together.
On a side note, my main beam was sagging 1 1/4". It was made of 4 2x6, span 25ft with 2 posts in the middle. I wanted to replace it with a steel I beam, so i rented a 60 ton jack, 4 post jacks and bought a 4x4. Called up 2 buddies, grabbed 2 12's of ML Lite and started jackin. You shoulda heard the poppin and creakin. Loudest sh*t I ever heard, sounded like gunshots in my basement. Never seen 3 grown men duck for cover so fast.
It went without a hitch, new beam is in place.
Thanks again
Matt
Miller lite?!Ale makes a better lube, ya know? and Stout will be stronger to hold up a weight!Anyway, when we jack a house, we sometimes go slow, a little at a time as I described. That way the old wood and joints settle slowly overnite ionstead of fighting you - less chance for splits and pops that way.You've got the hang of it. The joists are just smaller baems! But it is better to save the beer for after when you are doing dangerous stuff.
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Taking the sag out is a minor technical problem. The effect it will have on the rest of the house that has settled into it's present shape may be the real determining factor. If, by jacking it up, you change the hang of the doors, cause more squeeks in the floors, break plaster or wall finishes etc. you may be best to leave the sag. Depends on how far you want to take the remodel.
Mano,
I have a complete gut/remodel goin on here. Im about 2 months into a 3 yr project. Baby steps. Im doin the 1st floor in halves, and the half i still have plastered is cracked all to hell.
How bout this. Wall demo. 1/4" louan, paint and wallpaper, 3/8" drywall, plaster, lath. Talk about debris.
Im enjoyin the ride tho. Nothin better than puttin in 8 at one job, comin home and puttin in another 8 at home. I just gotta get the 1st floor livable by May 20 so when the wifey moves in she at least has a floor to walk on.
Still smilin
Matt
I have to say that I'm with manoman here. I would not try and take all the sag out of the old, but rather jack it a little at a time like Piffin suggests until it's good and tight, until you start to hear the first real creaks, and let that be it. Then I would sister your new on either side of the old with through bolts. If you lift that baby too much, things are going to shift in other parts of the house because of the transfer of stress.
I would do it this way unless of course your sag or bump in the structure above is unlivable, then that's a whole other can of worms.
"I am not planning on finishing the basement ceiling so its no big deal to deep them sagged and nail rightt to them. Just looking for advice from someone who may have done this before, thanks."
If you’re not worried about the sag then why can't you just put the new joists in independently and not even worry about sistering them to the old joists. Now you have a whole new floor. I've done that several times before. Why touch the old if you’re going to install new? There’s nothing wrong with doing that. When we do add-a-levels now we don’t sister them next to the old. We run them on plates or we run them on top of the existing.
If you’re not worried about the sag then why can't you just put the new joists in independently and not even worry about sistering them to the old joists
I was thinkin since they are already there why not use them for a lil extra strenthg, no? Or is an undersized joist like this more of a liability?
Matt
"I was thinkin since they are already there why not use them for a lil extra strenthg, no? Or is an undersized joist like this more of a liability?"
You don't need any extra strength with only a 15'span with 2x10's. A 15' span for 2x10's is done every day around here. These existing joists are not a liability as far as I'm concerned since it's been there for 101 years. Besides if you frame with the 2x10's that becomes the new floor and there's no load on the existing 2x8's, there just holding up themselves.
Joe Carola
Edited 3/1/2006 7:57 pm ET by Framer
What do u think about this.
I am looking at putting radiant heat in my 1st floor.
Option1) staple pex tubing underneath sheething and have the plywood transfer the heat or
option 2) nail 2x4 sleepers 12" oc, lay down pex tubing between, fill in with 1 1/2" lightwieght concrete
In your, or anyone else's if u care to chime in, opinion do you feel that sistering these joists will allow me enough support to hold the floor.
This is the main reason I wanted to keep them there.
What do you think?
Matt
Now you have just gone and cahnged the whole thing.You need to calc what your loads are going to be with that float on above, and frame enough to handle that. My advice was fgor a wood floor since that is what you have. I would frame to handle the loads, and not do a thing about jacking it up. The lightweight gypsum floor can level you out.
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