Air sealing foundation to framing

[Yookdew]

My garage was recently framed and I am looking for a good exterior caulk or sealer to seal the OSB sheeting where it meets the block foundation before I have vinyl siding installed. Does anybody have suggestions on a good sealer that will stick to both the wood and and the concrete block?

From my understanding, it is better to seal this area on the outside of the structure VS sealing the bottom plate to the block on the inside of the structure. Any thoughts or opinions on this or what type of sealer to use?

Thanks

 

[Hank11]

How much block do you want to cover? Or is this literally just sealing the osb edge to the block?

I like Vulkem 116 or Dymonic 100. Follow instructions and they will do a great job.

You might also look at tapes made for this purpose. Just sealing the edge of osb to block doesn’t do much to help the osb live longer. 12” wide tape over the joint might help the osb survive.

You might post a picture to help get better answers.

 

[Yookdew]

How much block do you want to cover? Or is this literally just sealing the osb edge to the block?

I like Vulkem 116 or Dymonic 100. Follow instructions and they will do a great job.

You might also look at tapes made for this purpose. Just sealing the edge of osb to block doesn’t do much to help the osb live longer. 12” wide tape over the joint might help the osb survive.

You might post a picture to help get better answers.

I was planning on just sealing the edge of the OSB to the block. My thoughts were maybe a thick bead of caulk where the OSB meets the block or using something like a liquid flashing that could be spread on thick and extend and inch or so above and below the joint.

The main thing I want to do is seal out air and bugs from the area where the bottom plate meets the block but I'm not sure of the best way and what product to use.

 

[Hank11]

If the osb is spaced off the concrete you can fill that gap with a bead of caulk. You may need backer rod. Read up on what it does for a caulk joint. If the osb overhangs the block, you can caulk that 90* corner. But if the osb is touching concrete that”s not so great. Again a picture or drawing of the detail will help get the best advice.

 

[Yookdew]

If the osb is spaced off the concrete you can fill that gap with a bead of caulk. You may need backer rod. Read up on what it does for a caulk joint. If the osb overhangs the block, you can caulk that 90* corner. But if the osb is touching concrete that”s not so great. Again a picture or drawing of the detail will help get the best advice.

The bottom edge of the OSB sheeting slightly overhangs the top of the block foundation. I will try to get pictures of it tomorrow and post them since we are in the middle of an ice storm right now.

 

[Yookdew]

These pictures may work to give an idea of what I am working with. I will get some better pictures tomorrow.

 

[Hank11]

These folks make good stuff. https://protectowrap.com/building/
They make some self stick membranes that would be useful for your job.

Your picture seems to show the osb held up about a half inch and flush with the block. You could tape off the block about an inch or two down, then caulk the joint, and strike off with a putty knife or spatula. Talk tomthe siding guys to see where the siding will stop so you don’t have gnarly caulk hanging out.

 

[Rusted Nut]

Seal the inside. You don’t want to seal the outside at the bottom, you want moisture to be able to weep out. No, you should have moisture behind the OSB, but then again there’s a lot of things that shouldn’t happen.

 

[nadogail]

I have found that a good coat of paint can really help prevent moisture intrusion. You have to put it on during construction, not after.

 

[nadogail]

When my house was built, 1988, the builder didn’t seal the walls to the slab. We discovered this when the carpet got dirty from the outside dust being trapped by the Carpet Pile. The builder paid for caulking the wall plates to the slab when we replaced the carpet.

 

[Firstram]

When my house was built, 1988, the builder didn’t seal the walls to the slab. We discovered this when the carpet got dirty from the outside dust being trapped by the Carpet Pile. The builder paid for caulking the wall plates to the slab when we replaced the carpet.

A buddy used to own a carpet cleaning company, that's very common!

 

[jollygreengiant]

Well it looks like you are using house wrap, in that case it should extend slightly past the edge of the osb over the concrete. Keeping your air barrier layer in one continuous plane is the simplest and most effective. I used a mix of 3m all weather flashing tape and blueskin flashing tape to seal the housewrap to the concrete, with 3m spray adhesive to help the tape stick to the concrete.

 

[jack stand]

A masonry surface is very difficult to seal (permanently) with adhesives or tape especially in a "surface" application such as a concrete to the bottom of the sheathing vs say a Crack situation.
Presumably they installed at least a common foam type "sill seal". If there's any areas where the sheathing is "short" enough to expose the plate/concrete horizontal joint, this is where you'll have your best chance of long term success.
If you're concrete was nice and flat at the top, any common sill seal applied between the 2 surfaces should be plenty for a garage situation. The overhead door(s) sealing negates you extra efforts to the wall plates in my observations.
Like all sealing (wind, bugs, water), it's the weakest link that gets ya.

 

[NUTTSGT]

I spray-foamed the bottom 3" of the inside wall cavity with Great Stuff.

I also have sill seal under the sill plate and I caulked the edge (on the inside) where the sill meets the block. However, the top course of block were also filled with spray foam.

 

[AdamMopar]

Liquid flashing will work well for you. When we built our house I did liquid flashing, I used the zip system brand, and did between the concrete foundation and up 6 inches on the OSB. Then brought the house wrap down over it. I do believe if you have traditional sheathing and house wrap that is a good way to prevent future problems.

 

[Kaizen]

I just used the zip liquid flashing to seal my 120 year old sill to fieldstone foundation. Highly recommend it. Use gloves. I made the mistake of not smoothing a section out and getting that stuff off took a wood chisel.
but no way would i seal osb like you are talking. If i were you i would actually cut off the bottom two feet of that osb, use the zip liquid at the sill, then put up pt plywood or zip. Just my feeling that water splash up will destroy that osb.
I got this and a sausage gun

https://www.amazon.com/gp/product/B01N5CXVKA/?tag=atomicindus08-20

 

[Yookdew]

Do you have any estimate on the coverage of the Zip liquid flashing? I would have about 112 feet to seal, guessing approximately 3 inches wide. I'm trying to estimate ow much I would need.

 

[Hank11]

The Zip liquid flashing is great stuff however, its a lot more expensive than other similar pirpose materials you could use because you’re not using Zip panels. But you won’t be wrong using it. I use it for Zip panels and window and door openongs when using Zip panels. When sealing the bottom of non Zip sheating I use the Tremco products I specced in my first post.

Look at the local suppliers - they sell Zip liquid flashing lots cheaper than Amazon. Same for the Tremco products.

My guess is you will need about 15 sausages.

 

[ptabatcher]

You could also look for Polyguard, formerly Polywall. https://polyguard.com/residential/products/blue-barrier-lf

Prosoco R-guard is also an option. Based on Amazon prices for Zip, both Prosoco and Polyguard are cheaper.

For any of them, wear gloves.

 

[jollygreengiant]

I just used the zip liquid flashing to seal my 120 year old sill to fieldstone foundation. Highly recommend it. Use gloves. I made the mistake of not smoothing a section out and getting that stuff off took a wood chisel.
but no way would i seal osb like you are talking. If i were you i would actually cut off the bottom two feet of that osb, use the zip liquid at the sill, then put up pt plywood or zip. Just my feeling that water splash up will destroy that osb.
I got this and a sausage gun

https://www.amazon.com/gp/product/B01N5CXVKA/?tag=atomicindus08-20

OP said he is using housewrap. So long as there is a bit of a gap between the edge of the OSB and the concrete he'll be fine. There won't be any water getting splashed onto the OSB because it's covered by housewrap.

 

[Chris705]

Look at Fentrim by Siga.

 

[Kaizen]

OP said he is using housewrap. So long as there is a bit of a gap between the edge of the OSB and the concrete he'll be fine. There won't be any water getting splashed onto the OSB because it's covered by housewrap.

assuming he doesnt seal as i pointed out, the edge of that osb will be exposed to splash up if too low to ground. normal osp is like a wick

 

[Kaizen]

Do you have any estimate on the coverage of the Zip liquid flashing? I would have about 112 feet to seal, guessing approximately 3 inches wide. I'm trying to estimate ow much I would need.

sorry i was sealing nail holes and such as well as the sill so not easy to estimate. used sparingly i'd say at least 3 or 4 of the tubes i listed.