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Caulking around windows


robert1966
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I always call for sealant at all junctions between door and window units and any masonry veneer or J-channel.

Did a home a while back where many of the windows around the outer edges had condensation on the inner pane of fairly new insulated glass replacement windows. None of the above junctions were sealed, and you could literally feel chilly drafts at some of the inside window perimeters.

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Depends on the installation. Caulking around brick veneer to the window is useless if the window is in new construction with a nailing flange. All the caulk and flashing that matters is hidden from view once the veneer is installed. The brick does not keep out wind or rain, that is why there is a drainage plane at the wall sheathing.

Retrofit window is a different story because of the limitations for installing proper flashing and caulk since there is no nail flange.

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Like Texas Jim said, it depends on the window & the siding.

Surface applied caulk is pretty much worthless most of the time. The good stuff happens underneath, in places that you can't see.

Of course there really shouldn't be caulk at the top of the window above the flashing.

- Jim Katen, Oregon

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I always call for sealant at all junctions between door and window units and any masonry veneer or J-channel.

Did a home a while back where many of the windows around the outer edges had condensation on the inner pane of fairly new insulated glass replacement windows. None of the above junctions were sealed, and you could literally feel chilly drafts at some of the inside window perimeters.

That condensation has more to do with the relative humidity in the house and the quality of the window in question than it does with whether it was caulked properly or not. Windows do not manufacture water, it has to come from another source, ie:high RH.

Condensation occurs around the perimeter of insulated glass units because the metal spacer is conductive and that is the coldest part of the assembly. Better quality insulated glass units employ high performance spacers to minimize the conductivity at the edge of the glass. Some use materials like stainless steel and silicone foam while others use a channel rather than a box shape to reduce surface area.

While I have seen instances where drafts around poorly installed windows (and high air infiltration rates of cheap units) have contributed to cooling surfaces to the dew point it's pretty rare that it's the root of the issue. The air leak is generally big enough for the warm moist air to migrate out to the cool dry air and disipate it's water vapor outside.

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