Issues with Garage Sill Plate/Foudation/Grading

[MyManMitch]

Hi all, purchased an older home this past April. Got a great deal, but knew it was going to have issues to address. This is my third home, so not new to house problems, fixing things, etc - I've learned a lot over the yeards, but I'm no master builder/carptener either.

I noticed the previous owners (owned it for 42 years) built up a flower bed along the garage up and over the siding. I removed several inches of dirt along it to explose the foundation again as having your foundation and siding buried is a bad idea.

Today I was going around the house trying to seal off any gaps, and started paying close attention to this area. In spots the sill plate looks pretty rotten and have large gaps basically exposing the wall cavity for the garage.

I've done a bit a research... it seems the proper thing to do if I'm really concerned about the integrity of the sill plate, is to have the garage jacked up to replace it (no small task, probably big $ to hire it out). I don't think I really want to do anything like that until I'm ready to replace the siding in a couple of years. Trying to figure something out that will keep the pest and elements out and get me by for a couple of years.

I've attached some picture to give you an idea of exactly what is going on.

Couple other notes, the siding is aluminum. House was built in the 60s. The attached garage was an addition at some point, I think in the 80s, but the actual foundation of the house sits several inches higher the garage foundation. I've got good grading on this side of the house and could remove even more dirt to bring it down to the yard.

I thought I could use spray foam (large gap and cracker filler) and go town... but want to see if anyone has any other suggestions/ideas. I've also thought I could install a pressure treated 2x6 or 2x8 along the sill, but over the siding - would probably be ugly but might help protect things more?

Thanks ahead of time for any advice.

Mitch

[Sibley]

Your garage is mine's twin. I'm sorry. The big difference between you and me is my garage isn't attached to the house. I got very lucky - I made a friend who is also an electrician, plumber, ex-general contractor, framer, mechanic, etc. I don't think there's much this guy CAN'T do. Couple years ago, he did jack up one side of my garage, pulled out all the rotten wood, replaced the sill plate, sistered the studs, replaced the windows and door, etc. Basically, fixed the garage. Mine was not structurally stable before the work. If you leaned on one corner the whole garage would sway. It's still a POS garage but at least it's functional. In my case, the slab is below grade and is also broken into multiple pieces. Maybe I'll get lucky and my neighbor's tree will fall on it so insurance will pay for a replacement. 

Keep digging out around your garage, get the dirt away. If you have a dip, then I've got a post on here from earlier this year trying to figure out what to do about it that might be helpful. That at least will help stop things from getting worse.

[affordablehousing]

I would definitely get the dirt further from the sill plate. I think a lot of this depends on how correctly you want to deal with this. The "correct" thing would be to shore the wall from inside, take off a few courses of siding, and do as Sibley said, sister new studs and cut the rotten parts off the old ones, replace the mudsill, and bolt it to the foundation, but it is a garage, and every house is a little rotten, so perhaps you just spray some boracare on the wood to prevent it from rotting further, and close it up and don't think about it. I do think the regrading and a piece of flashing should protect it from future water.

[lthenderson]

When I moved into this house some eight years ago, one of the first tasks I did was to jack up one side of my garage that had been built up on a berm of dirt and settled at some point in the preceding 40 years. I had to do this to get the garage door opening to be straight with the door again and also to line things up so I could side the thing and have it look nice the next year. I removed the drywall partway up the inside wall, used a sawsall to cut any fasteners between the studs and the sill plate, attached a steel beam to the studs using long screws. The steel beam spanned about five studs at a time. The steel beam was attached high enough that my largest bottle jack would fit underneath it. I then used a couple bottle jacks to slowly raise that section up a bit, and add another 1-1/2 thick plate in the lowest spot and lesser shims as I worked my way back to where things were level. Took me about an afternoon to do that. Spent quite a bit more time afterwards adding more anchors since the old ones were no longer long enough, redoing the drywall on the interior and flashing the outside in preparation for the siding which I did the following year. Since the beam was salvaged, all it cost me was my time, a few boards of treated lumber and drywall.