# Sealing gap between vinyl siding & foundation



## cmjb13 (Apr 2, 2008)

Was doing some research on how to stop mice getting into the house and decided to take a mirror and go along the bottom of the vinyl siding where it meets the foundation. I noticed quite a few holes that were big enough for mouse entry.

Can the gap between the vinyl siding and the foundation be sealed with foam or must it be left alone for drainage/ventilation purposes?


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## woodworkbykirk (Sep 25, 2011)

foam works perfect for sealing againsts drafts. thats one of teh worst spots for it to occur.. only thing is the mice will still burrow through it.. pick up some steel wool first and stog the holes with it first. then fill the rest with foam. they cant get through the wool


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## cmjb13 (Apr 2, 2008)

woodworkbykirk said:


> foam works perfect for sealing againsts drafts. thats one of teh worst spots for it to occur.. only thing is the mice will still burrow through it.. pick up some steel wool first and stog the holes with it first. then fill the rest with foam. they cant get through the wool


Let me clarify.

Here's the part I'm referring to where the vinyl siding meets the bottom of the foundation

http://home.comcast.net/~cmjb13/foundation.jpg

Now, if I look upside down I see this...

http://home.comcast.net/~cmjb13/gap.jpg

Basically, there's a gap, but it's mostly filled with insulation already. In some spots it's not. Is it safe to put expanding foam all along this gap around the entire foundation? Or must it be left alone for drainage/breathing purposes? I've heard if you seal this gap, water will soak into the walls causing mold, mildew, and rot.


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## joecaption (Nov 30, 2011)

That second pictures to blurry to really see what's going on.
But it looks like someone messed up and the rim joist over hangs the foundation to much.
It should have been even with it and the sheathing runs past the foundation to seal that area.
I'd take a measurement to see just how far that siding sticks out past the foundation. If it's 3/4 or more I'd concider removing the bottom row of siding and starter strip and install a piece of 1 x 6 vinyl lumber then a piece of Z moulding then replace the starter strip with J moulding, reinstall the siding.
This would 100% seal up theair leaks and cover all the gaps where critters can get in.
A simpler way would be to seal this up from under the house with 2" thick blue foam and some expanding foam to seal up any gaps.
Trying to do it on the outside will just make a mess.


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## HomeSealed (Jan 3, 2008)

Looks pretty normal to me... You _could_ use foam there but its gonna be messy and probably not turn out well. Worst case, if you put too much it could over-expand and make your siding look lumpy. Best thing would be to bend a piece of aluminum in a matching color and then caulk it to the foundation. Only problem is, that is usually done prior to siding installation so it is easier to attach.
You aren't going to cause any harm to drainage, if you look at the bottom edge of the siding, there are weep holes built in. You can even see one in your second pic.


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## woodworkbykirk (Sep 25, 2011)

thats normal. as long as the siding and house wrap laps down over it moisture cant get up in there. as for drafts if you can get in at floor cavity from inside you can cut rigid foam and fit it between the joists then run a thin bead of spray foam at the perimter of each peice of rigid to better seal against air loss


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## cmjb13 (Apr 2, 2008)

I did notice one section that has quite a sized gap between the vinyl and the plywood. It's probably been like this for quite some time. There is no other gap along this wall. The rest of the siding is flush with the wood. I plan on putting copper steel wool so it won't rust. Would you agree it's not a good idea to put foam in addition to the steel wool as it will pull away the siding along the same wall?

http://home.comcast.net/~cmjb13/big_gap.jpg
http://home.comcast.net/~cmjb13/big_gap2.jpg

I also see a thin corner strip. Can I seal the bottom of this with foam as well or must this be kept free?

http://home.comcast.net/~cmjb13/strip.jpg

Appreciate the help.


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## darthsmozers (Dec 31, 2011)

Nothing to add except this is a good question. Thanks to all who are replying


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## joecaption (Nov 30, 2011)

That inside corner needs to stay open so any water that gets inside of it can drain.


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