Garage 2×4 wall is a little below grade and rotting
The guys did a great job answering my questions about my garage in episode #132 of the FHB podcast. I started this weekend, opened up the first wall, and of course found a major problem. The outside wall of the garage sits below grade by about a foot. The sill plate is completely rotted away in the corner, and showing some serious moisture along its length. The previous owner must have had the PT patch job put in and the recovered it with the drywall so no one would notice.
I’m planning to excavate this weekend and see what’s going on. Maybe the newer retaining wall is part of the problem. I can’t dig lower that the slab or else I won’t be able to pitch the pipe to drain to daylight across the driveway.
I’m thinking dig down to slab level on the outside, use a pond liner to protect water from getting to the sill place, and place a perforated drain pipe. Cover with landscape fabric and grave and drain the pipe through a new hole in the little retaining wall across the driveway. Then obviously replace the sill plate with PT and maybe sister those 2x4s with PT as well.
Any other considerations?
Replies
You've got to keep the water below the floor. I'd make sure you have gutters and would lead the downspout into your preforated pipe so the water drains well away from the house.
Replace the rotted stuff with PT, use cement board for sheathing, and coat the outside with foundation coating.
My parents had exactly the same issue this summer, and the bottom 8 inches of the wall and framing was rotted along one wall and the back corner.
Here's how we fixed it:
- Built a temporary support wall: Screwed 4x4's to the ceiling joists down the length of the wall, sitting about 30" away from the wall. Put 4x4 posts at 4' intervals. We jacked up about 1/4" near each post and slid them in.
- Cut 17.5" off the bottom of the wall. Snapped a line, ran a skill saw down it. Cut the studs off with a sawzall. Pulled everything out. Pretty cool to see the whole side of the garage floating in the air.
- Layed up two courses of block
- Fit in a PT sill plate. Had to slightly trim a few studs.
- Nail everything off and add bolts
- Re-trimmed the bottom of the outside wall, which was now 8" above the dirt line.
- Remove the support wall.
In my opinion, this is the right way to fix it. I have done a number of these, including sidewalls where people tried the "put plastic in there" idea - lots of moisture and rot. I wouldn't recommend that route.
It took us 3 afternoons / evenings to do the the whole thing. Dad's a mason (and 78) and I used to be in the trade. So it was pretty straightforward for us. If you're DIY, maybe a week of work.
Hope this helps.