Sealing stuff

msaeger

I was reading this article about sealing stuff and they talk about calking where wires go into boxes and bottom plates. What should I use to calk with?

http://www.buildingscience.com/docum...ywall-approach

Windows on Wash

A good latex based sealant will work fine in these type of shielded applications and will be the least offensive to the nose and wallet.

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AGWhitehouse

God that sounds like a horrible idea. I know how good it looks on paper, but functionally that's a nightmare. Both in application and renovation. I would suggest getting the foam seals that go between the box and cover plate and leave the caulking at the store.

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msaeger

What would caulking where the wires go into the box hurt?

AGWhitehouse

I'm sure there will be plenty of people who'll disagree with me, but it sounds like alot of labor for a minimal gain.

Maybe the plastic boxes are easier, but if you have an older home with metal or you retrofit with quality then you have a box similar to this: http://image.made-in-china.com/2f0j0...nduict-Box.jpg There are a dozen or so screw holes along with the wire entry points. Even if you caulk all those screw holes the corner edges of the box are only held together by a compression screw. So now you're up to covering the entire box in caulk...see where I'm going? now multiply that by however many boxes you have...ouch!

Hence why I say treat the box at real air entry point (the wall surface). The make foam plate backers much like this one: http://images.lowes.com/product/conv...78038193xl.jpg

Take a minute or two and when it comes time to retrofit they come off without the mess and fuss of caulked wires and boxes.

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msaeger

The is new construction I am finishing the upper level of our house that was never finished. Baby on the way so now we have to do it

I have boxes like this one LINK

It probably doesn't really matter that much but I figure it would only take a few seconds to seal the couple holes where the wires go in the boxes.

AGWhitehouse

Plastic boxes are easier since the only holes are where the wires are. I mainly deal with metal where the caulking process is far more of a laborious task...

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Windows on Wash

Foam gaskets don't work that well without caulk and are done improperly about 85% of the time.

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AGWhitehouse

Please explain because this statement makes no sense to me...

Can this be verified? Or did you make it up? How often is caulking of a metal box done properly? I would bet money it's less than the install of the foam gasket.

Remember that everything can be made to look good on paper. Hell, the US Government looked awesome on paper when it was starter, but look at the mess now. There is a balance between form and function and if one process works really good but is a bear to install then essentially, over the spans of contractor ability, it will function the same as the works good product that is easy to install.

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Windows on Wash

I agree with you wholeheartedly about the US government.

In terms of the gaskets, we still see copious amounts of leakage during depressurization tests with the gaskets installed around the outlets.

Many of the switch plate covers do not compress the gasket into the drywall and form a proper seal depending on the style of the cover.

Combine that with the fact that most people throw spade plug gaskets in the center and do not install them over the plug, you get air leakage through the outlet itself.

The best way to do it is to remove the cover, put a bedding bead of caulk on the drywall around the outlet, stick the gasket into that caulk, replace cover, install gasket over the spades on the electrical wire or install child safety cover with the gasket over it.

I am not saying that caulking of the metal box should be your first option because many drywallers leave huge gaps that would require foam or backer rod to cover it, however, just slapping the gasket up there does not do the trick either. The combination effort is ideal.

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Gary in WA

Yes, caulk or foam the boxes and the wire inlet areas. Wrap them in electrical/packaging tape, anything to get air-tight. You don't want the conditioned house air getting to the f.g. to negate the R-value and possibly wetting it; http://www.nrc-cnrc.gc.ca/eng/ibp/ir...ling-heat.html

Foam outlet gaskets do work and leak because the receptacle is assembled pieces to make the whole. As said, use them both. Caulk along each stud/sheathing/plate joint for air sealing, caulk the wire/plumbing holes in top/bottom plates, pp. 18 and 21, here;
http://www.engr.psu.edu/phrc/trainin...ngbarriers.pdf Caulk at the bottom plate/sub-floor joint because the rim joist moves in thickness with the seasons. If open basement or attic, foam the wiring/plumbing holes there as well.

Add some foam board behind the outlet/switch boxes on exterior walls to make-up the loss of R-value due to thickness loss there. No insulation on house side of plumbing drain lines or supply, use foam board behind. Seal the outside porch light box well. Use nail-protects at wire/plumbing areas if closer than code.
Read some of the latest posts on “Drywall” or "Painting" if needed. Also "search box" at top of each page.


Gary

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