Sealing bottom plate & sheeting

Hi,

I'm building a lean-to shed (see progress thread here). After removing the old siding I nailed 15/32 plywood.

Now that it's all done I have a couple issues I need solutions for and I'm hoping the smart folks out there can over their 2ct.

Problem #1 : The old garage stud wall and sill plate are not completely flat and straight. There is a little of wave going on. I plan on building a another stud wall (so I can apply some insulation and support the rafters) against the garage. I plan on build the wall straight and use shims where needed before anchoring the 2 walls together. Do you foresee any issues there? Anything I should be mindfull about?

Here is some visuals:

.

Problem #2: When I nailed the plywood sheeting I favored keeping the bottom of the sheet level and straight over touching and sealing that sill plate. There is also a few gaps here and there between sheets as I go up the wall. The wall won't be exposed to rain anymore but I want to eventually seal the heat (and cool) in the garage by applying proper insulation (both inside and outside). How should I seal those gaps? Right now my though is to get some foam sheet insulation and fill all of those gaps on the sill plat using expendable foam to keep it in place. And for the gap between plywood sheets simply use sealing tape like Tyrek? Thought?

More visuals of the problem:





Thanks again for the advice and ideas!

naf305 said:

Click to expand...

I don't know if it's an option at this point, but can you pull the plywood off and then saw cut a taper on the lower edge so it matches the lower plate? Alternately, cut a tapered sliver from a scrap piece of plywood to fill in the gap, but that may be difficult to fasten in place since it would be so narrow. I'm thinking that gap as is will be like a superhighway to mice or other critters that will want to move in for the winter.

Your new floor will be above the gaps. Just insulate it with spray foam to keep it critter proof. Or just cover it with strips of ply.

forAK said:

Your new floor will be above the gaps. Just insulate it with spray foam to keep it critter proof. Or just cover it with strips of ply.

Click to expand...

That was my thinking. I might use piece of foam boards for the wider gaps and glue it all together with foam spray. I'll spray the bottom part of the stud wall from the inside of the garage too.

What about sealing the plywood sheets? Calk? Tape?

You say you're insulating the garage. You can just leave it as it is cause you'll have some sort of vapor barrier inside. I wouldn't sweat it.

By the time you install the ledger boards/rim joists and floor for the shed there's not really going to be any gap there at all.

forAK said:

You say you're insulating the garage. You can just leave it as it is cause you'll have some sort of vapor barrier inside. I wouldn't sweat it.

Click to expand...

So you bring up a good point about the vapor barrier. I am in fact planning to insulate the garage. On the 3 other sides I am planning down the road to remove the siding, sheet the wall with plywood, a vapor barrier, foam board (for extra insulation) and then new vinyl siding (that will look like the old staggered cedar shakes).

Now on the wall shared with the shed, the lean-to wall. I was planning on putting any vapor barrier. Would that be a problem? Should put one on the outside now while the wall is just fresh with plywood before I raise the stud wall of the shed?

I guess if I did that it would take care of sealing those gaps the plywood sheets meet.

I read also that I could use some silicone calk on the seams. Thoughts? The goal is really to seal the cold air in the winter.