Ok, here goes...
We're putting in a bathroom window where one did not exist before, so our
original intention was to order a new construction window. However, since
the (insert name of large home improvement store) guy said it would be hard
to get the nailing flange underneath the aluminum siding on the outside
(it's a small window in the middle of a wall so we don't want to remove the
siding) he suggested just ordering a replacement window. Ok, we ordered a
replacement window. So far so good.
We've rough-framed the opening with standard 2x4 studs but now things are
getting a little murky. The studs have their normal depth of 3 1/2" and add
to that about 1/2" for the outer wallboard and another 1/2" roughly for the
aluminum siding at its widest. Coming inside from the studs, there's 1/2"
for the drywall (and a negligible width for the tub surround that we'll just
cut to fit). So the wall depth totals 5 inches.
The window is 3 1/4" deep. The J Channels for the aluminum siding are
1/2" thick. So now we have 3 3/4" inches of stuff in a 5 inch deep hole.
Problem number one: the depth placement of the window. The window's
bottom plane is not precicely flat, but rather has two 3/8" wide 1/8" high
ridges almost at the front and back edges of the assembly. If we center the
window on the studs, it will fit stably there but the J channels won't sit
flush against the window and still be able to fit around the aluminum siding
because of the 1/2" wallboard in between. If however, we push the window
towards the outside so it sits flush against the J channels, the front 3/8"
ridge will be resting comfortably on the stud but the back ridge will be
sitting on the wallboard (which seems less stable).
Problem number two: the interior. Either way we place the window, there's
still the issue of what to do to cover over the width of the drywall.
There's not really room to add jambs around the top, bottom and sides of the
window because it already fits precisely into the rough stud framing
(roughly 1/4" on all sides). Add to that the issue of it being right above
the shower so we're trying to find a water-resistant solution. Does anyone
know of a plastic or vinyl L-shaped strip that can be caulked to the window
and the tub surround/wall?
Thanks for any brilliant insights,
PS: We've nearly finished gutting and remodeling our bathroom, so we've been
able to figure out or research most things, but the web has precious little
info about replacement-less replacement window installing. Go figure.
That is because replacement windows aren't designed to be installed
that way. If you have the time order the correct sized new
installation window. Pulling off a little bit of siding will probably
be much easier than what you are dealing with now.
If you can't wait then you need to weatherproof the window on the
outside then worry about the inside. It sounds like you are mounting
this window high so water from the shower shouldn't be a major concern.
I would put some metal flashing on the outside so that water can't get
in then try and make it look right. Replacement windows require
moulding on both sides to cover up the gaps.
When you are ready to screw it into the studs make sure you use shims
between the window and the studs so the frame doesn't warp when you
tighten it up. Also spray in the expanding foam designed for windows &
doors, again so the frame doesn't warp (gap sealing foam can easily
compress a vinyl window frame.
What you describe is normal. Generally a flat piece of 1x stock is added to
the inside after the window is installed pushed to the outside to bring the
opening flush to the inside edge of the drywall (actually 1/8" more is
better). Then the window can be framed on all four sides with your choice of
Your case is different because of location. A pricey option is having some
faux marble slabs made and fitted. Lower cost options can be field
engineered with a trip to the BORG. In the wood molding sections of most
you will find plastic/composite trim pieces. It is just a matter of putting
the right combination together. You might be able to use some of the cement
or composite based boards that are sold for fascia in lieu of the 1x board.
Then add pvc casing and caulk really well.
Did you actually cut out a portion of the surround? And is this going to be
Well it looks like you have gotten yourself into a bit of a jam,
unfortunately. The guy at the bigbox store was stupid, or at the very
least very misleading. This is what you should probably have done,
(1) Use a new construction window. You'd have to pull back the siding,
and I suppose with aluminum you would have to be careful not to bend or
crease it. With vinyl you could bend and stretch it to fit in the
window's built-in J-channel. Or you could get a window without a
J-channel and then add your own. Latter is probably the best option for
or, (2), you could go with a replacement window. Start by building out
your window in the old fashioned way: rough frame, then build a box of
finish quality wood (sides, top, and window sill). and all the trim on
both the inside and the outside, then paint the whole thing, then
insert your replacement window inside this box. It would end up looking
like you had a wood window there that you replaced.
At this point, I don't see any great options for you. You could rip out
the studs and the top and bottom 2x4 plates, make the opening 1.5
inches bigger on all sides, then go with option (2) above. Or you could
buy a slightly smaller replacement window. Or you could cobble
something together to make it look not terrible. E.g. Finish the window
frame and trim first. Then put the window in the middle of the width.
Don't worry about resting it on the bottom 2x4 plate versus drywall or
whatever... it is the four side screws that hold the window in place.
In fact, it is fine if the whole thing kind of hangs a tiny bit
suspended above the bottom plate. As for the trim, get somebody who can
make (i.e. bend) aluminum trim, and have them make you an exterior
frame. In this case, the aluminum would go under the siding, form a
J-channel, then wrap back inside the window opening. Have the aluminum
go all the way the full 5 inches deep right to the inside of the wall,
so it covers the entire studs. Then you can put your window in place.
Then you can layer some 1/4" thick trim on top of the interior aluminum
showing, and make a frame around the window with trim pieces. And be
sure to caulk the hell out of everything (i.e., under the aluminum,
between aluminum and your window, under your trim, etc.), since it
would be too easy for water to get inside your wall.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.