How to air seal penetration on wall that is already sided?
Rocky12
| Posted in Energy Efficiency and Durability on
Hello,
I am installing a mini split in my house and I have to drill out a hole through the wall (2 1/2″ pipe) to run the line set through. Obviously I can’t air seal from the outside. Is spray foam my best option here (on the inside)? Any other options?
If so, can you please recommend the best product I can buy at home depot/lowes since I need to do this today!i
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Replies
Rocky,
You didn't tell us what type of siding you have.
You might consider installing an exterior mounting block -- these are available for walls with vinyl siding, or you can make one out of 5/4 lumber for a house with wood siding. The hole can be drilled through the center of the mounting block.
If you go this route, it will allow you to seal the penetration from the exterior (to the sheathing) before installing the mounting block. You can seal with canned spray foam (OK, but not great), caulk, or high-quality tape (the best option).
Rocky,
Here are some links to products you might consider:
http://eco-buildingproducts.com/product/quickflash-hvac-flashing-panels-weatherproofing/?gclid=CjwKCAjw7MDPBRAFEiwAppdF9JPXvDOx4_iwDR6CjXmxTpkG8U7aV54lawkDw2is-pMVAEax7V3l9BoC_ikQAvD_BwE&v=7516fd43adaa
http://www.energyconscious.com/quickflash-plumbing-flashing-panel-p-2ps.html?fee=5&fep=7042&gclid=CjwKCAjw7MDPBRAFEiwAppdF9LHyBRJCZYdaH416yQaRv0wS3o-VGCXb5MPDdIwgokEiKdCkvv05DxoCTzYQAvD_BwE
https://www.amazon.com/dp/B005GDGAMS/ref=asc_df_B005GDGAMS5232963/?tag=hyprod-20&creative=394997&creativeASIN=B005GDGAMS&linkCode=df0&hvadid=167155426463&hvpos=1o1&hvnetw=g&hvrand=3847856025295714228&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9004661&hvtargid=pla-313971310934
http://www.pipetite.com/
Video:
https://www.youtube.com/watch?v=zTtCOBnxAJg
Hi Martin,
Siding is Beveled siding.
How would a mounting block allow my to airseal from the exterior side? Are you talking about something like this: https://www.thisoldhouse.com/how-to/how-to-install-range-vent-hood
Or are you suggesting to drill the 2 1/2" hole through the sheathing and beveled siding and then from the exterior side, cut out a square from the beveled siding only? If so, I'm not sure how I would be able to get perfect square with a jigsaw, without cutting up my housewrap behind the siding.
My biggest challenge is sticking the pipe through, and then being able to tape the housewrap around the pipe (or gasket like you suggested..since I can airseal from the inside easier.
Rocky,
Yes, the "This Old House" video shows the use of a mounting block. However, Tom Silva was a little casual about the air sealing details.
If you are getting freaked out about the exterior air sealing details, you can certainly do most of your air sealing on the interior, and do a more casual job (with just caulk or canned spray foam) on the exterior if you want.
Yes, you will probably damage the housewrap when you make the hole. To bridge the gap between the damaged housewrap and the flashing or tape used for air sealing the penetration, you'll have to use high-quality tape or peel-and-stick, doing the best job you can under the circumstances. Sometimes -- but not always -- you can loosen the fasteners holding the beleved siding, using a flat bar, to get a 1/4 inch gap to help you tape to the housewrap.
Thanks Martin.
Would you say an angle grinder is the best tool for the job (without hitting the housewrap while cutting the square)?
Also, Is there any reason why a gasket would be preferred here over high performance peel and stick tape? To me, seems like the easiest would be to pull the pipe through, tape the house wrap around pipe, then slide the mounting block over.
Rocky,
Q. "Would you say an angle grinder is the best tool for the job (without hitting the housewrap while cutting the square)?"
A. I suppose it's worth a try. I don't think I would succeed with that approach. If you really want to try to do it, and you have a great deal of patience, you can cut a rectangle that is smaller in both dimensions than the rectangle you need to cut. This rectangle should be centered. Remove the waste (including the housewrap) after the cut is made. Then slide some aluminum flashing or a stainless-steel kitchen spatula into the opening, so that the metal is behind the actual cut you will make next, with the metal between the siding and the housewrap. Then make the final cuts through the siding, very patiently, with a sharp utility knife blade. It will take a while, but you can do it. (I wouldn't bother.)
Q. "Is there any reason why a gasket would be preferred here over high performance peel and stick tape?"
A. Either approach is fine.
Rocky,
You will find a multi-tool much easier to use than an angle grinder. If you don't think you will use it much afterwards Harbour Freight sells a pretty serviceable cheap one.
I agree use an Oscillating multi-tool.
I've had to do something like this a couple times when installing passive air inlets (4" tube), our siding is clapboards with a rain screen. I found that a fine detail saw (like this - https://www.lowes.com/pd/IRWIN-Dove-Tail-Detail-Saw/3612248), a small Dremel tool, and utility knife worked well for cutting the siding without messing everything else up.
These are condensed steps, you'll have to figure out some tricks and tape/caulk use based on your situation. Make your block (approx 8x8" 5/4 in our case), drill hole in block for pipe, pre finish block with stain/paint, and cut the siding to fit block. Drill through sheathing and drywall for pipe. Screw block onto sheathing (could use some caulk to seal behind), drip edge above block (try to tuck under house wrap and tape to sheathing). Run the pipe though the wall and out of block, maybe you could secure the pipe to the block with a small stainless brace.
If you keep things tight without making the hole too big for the pipe, using caulk is probably best, maybe doing this after the installation once things are stable. Hopefully that makes sense or at least the tool suggestions help.