PSA: I chose to sister the floor joist instead of replacing it and saved a full weekend of work.

After finding a soft spot in the living room floor, I spent about $40 on a 2x8 and a box of structural screws to reinforce the old joist, which was way faster than tearing out the whole subfloor.

3 comments

3 Comments

alice_harris351mo ago

That 2x8 you used, was it pressure treated or kiln dried? I'm just wondering because if it's not the same moisture content as the old joist, you might get some annoying gaps later when it shrinks. @fiona332 mentioned the deck repair with the car jack, and that's a smart move. Did you use any construction adhesive along the sister joint, or just the structural screws? I've seen guys skip the glue and end up with a little squeak that drives them nuts. Also, how many screws did you drive per foot? I usually go with 6 inches staggered but I've heard different opinions.

butler.mark2mo ago

Check the new joist is actually bearing on the sill plate, not just hanging in mid-air. I've seen guys just screw it to the side and call it good, which doesn't help much. Honestly, getting that solid bearing is the whole point.

fiona3322mo ago

Ever run into that? I had to fix a deck last year where the previous guy just toenailed the joists. I ended up using a car jack to lift it just enough to slide a proper joist hanger underneath, then bolted it right to the rim. Made a world of difference in how solid it felt.