I need to replace the sill of an exterior wall (load bearing wall that faces the outside the home). I ripped the sheet rock off and noticed some very old termite which was apparently treated years ago and there's no sign of new termites/damage.

There's a couple caveats though. The section that needs replacing is about 3ft of damage and its a corner. The section around the corner is only about 12 inches long before I hit the garage door (see pics).

What's the best procedure for replacing this? Can I just nail a support across the studs or should I support it vertically from the ground when I cut out the sill?

Also, this came right after I just built a full loft and put new anchors in....

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  • I know this is an older thread, but I am curious as to how this project worked out for you. Did you end up jacking the wall up or just digging the old sill out and squeezing a new one in. I have to make a similar repair, but for our entire garage 20 x 12.
    – DS84
    Jan 11, 2017 at 6:59
  • @DS84 I ended up jacking up the walls and supporting it with extra 2x4s so nothing moved when we slid the new sill into place. My recommendation would be to support the wall somehow (jacks, temp studs, or combo of both) when you replace the sill. I put some sill seal under the new section as well. We used treated lumber too.
    – justinw
    Jan 11, 2017 at 18:17

1 Answer 1


You need to set up a temporary wall under the ends of the ceiling joists of the garage, bearing onto the floor of the garage. Since the section needed is so short, you will only need 5 or 6 2X4s or 2X6s to hold the ceiling and lift the wall for the short time while you replace the bottom plate. If you need 10 ft studs to hold everything up, cut 2 of them in half to double up as top and bottom plates, then use the other 3 to use as studs cut 1/4 longer than needed for a snug fit to lift the existing a little. Get one stud jammed in, set another and with either a hydraulic jack, or by "bowing" them in, as in pushing in the middle of the stud to bow it so it in essence gets shorter between the 2 points until you release it, which will lift the wall a little. work all the studs together one at a time, one will help the other. Or 2 bottle jacks can do it all too, if you have 2 handy. 7 ton, maybe even 2 1/2 ton would work too. That corner, if there is no more than a roof over the garage, is pretty easy to lift up. You wont need much, an 1/8" will do.

This is all on the premise that the loft is contained under the roof with no 2 story bump out to house it, that the roof rafters bear on the top plate of the same wall that has the destroyed bottom plate.

  • So, I just put the supports under the loft's ceiling joists; they run parallel with the the sill and top plate (not sure if that matters. As far as jacking goes, I was under the impression for short spans, you could get away with just supports (no jacking). I am guessing you don't agree with that? I've even seen people just nail 2bys across the studs a little above where you cut to studs you aren't cutting and just doing it like that for small runs.
    – justinw
    Sep 23, 2014 at 4:00
  • The 2X temporary wall will go under the bearing wall. The plate has pressure on it form the weight of the structure. You could just hack it out and toss another piece in there with no jacking at all and since it is not a home just a garage, if it settled an 1/8" or 1/4" it may not matter so much to some. It would bother me. I would raise it enough to create small gap, cut the nails to the studs and dissect the plate into smaller pieces to get the old one out. Clean up the nails through the subsiding and reset a new plate.
    – Jack
    Sep 24, 2014 at 3:37

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