I'm installing Andersen windows in some new construction. Sheathing is 1/2"
CDX. The Anderson windows have a very small profile, i.e. the rim around
the window is only about an inch (the surface you see when you look at the
window head-on). So I want to add some casing around them, probably 3.5".
My concern is applying them in a way that will be water/weather tight.
Siding will probably be beveled WRC applied rough sawn side out with a solid
So my question is: does anyone know of good documentation on techniques to
apply such trim for a good weathertight seal?
I assume you know how to detail the building paper around the window.
I also assume you would trim the windows and butt the siding to the
trim. I use a head flashing (z flashing) over the top of the head
casing which is tucked under the building paper. if you are really a
fanatic, while you are siding, tuck a strip of 30# felt under the trim
on the side of the windows and bring it out over the siding course just
below the window, so the water that penetrates this joint is directed
to the exterior. this joint is also caulked, but caulk is doomed to
fail sooner or later. if you really, really want to do it right,
install the siding on furring strips to provide a drainage/ventilation
plane behind the siding.
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