Replacing 48x48 bathroom window with glass block unit
#1
10-12-06, 01:15 PM
Replacing 48x48 bathroom window with glass block unit
We are replacing a solid pane 48 x 48 double pane unit in our bathroom with a glass block unit which is 40 x 40. We have brick veneer on the outside. Unfortunately, the window company I have purchased the replacement window from does not do the opening reduction job. What do I need to do to reduce the opening to the 40.5 x 40.5 the window company says I need to have for them to work with? Do I need to remove the sheetrock from around the window opening or can I just frame on top of that to make the opening smaller? Also, do I need to just make the new opening flush with the existing aluminum window frame with respect to how far (remember, it is 48 x 48 and I will be reducing the opening almost 4 inches all the way around) it sticks out? Will I need to remove the existing aluminum frame or can we just trim over it after the new window unit is installed? The glass should come right out as the outside window frame has screws that retain the outer frame to the inner frame.
#2
10-12-06, 03:59 PM
Group Moderator
If I were doing it, I would first of all rip out the old aluminum window. You might be able to pull out some vinyl glazing strips on the inside or outside of the glass in order to get the glass out. If all else fails, put down some drop cloths, tack up some cardboard, and break the glass out. Once the glass is gone, the aluminum frame can be collapsed into the opening.
What you will then need to do is add some framing to the rough opening. You want your new rough opening to be centered in the brick opening. So you should find the center of the brick opening and mark it in your existing R.O. (which might be about 49x49)
Once you have done that, you can mark out where the edges of your new R.O. will be. (I'd suggest it be 41x41 for a unit that is 40x40, but maybe they have a reason for wanting it 40 1/2.)
At any rate, if you have 2x4 walls, use 2x4's... if you have 2x6 walls, use 2x6. Line it up exactly with the existing framing. If you end up needing some odd thickness to make the rough opening the right size, you can use OSB or plywood that is ripped down to the width of a 2x4/2x6. I would use construction adhesive between layers to prevent air infiltration.
Once you have the rough opening the correct size, you will cut some sheathing and apply it to the exterior of the rough opening. Whatever thickness sheathing is on there now is what you will use... OSB or plywood, doesn't matter.
Then you should apply some strips of building paper or felt around the opening. Apply a strip across the bottom, then strips down the sides. They will install the window on top of that building paper. Once it is installed, all 4 sides could be taped with window tape (Tyvek straightflash, Grace Vycor Plus, or similar) by taping the bottom first, then the sides, then the top. Building paper would then be applied over the top of the window, ensuring that the top of the building paper is tucked under any existing felt, if possible.
Insulate around the perimeter of the new window. You'll be able to put some strips of drywall around the interior framing you added then tape and finish that. Then you're new window will be ready to trim.
What you will then need to do is add some framing to the rough opening. You want your new rough opening to be centered in the brick opening. So you should find the center of the brick opening and mark it in your existing R.O. (which might be about 49x49)
Once you have done that, you can mark out where the edges of your new R.O. will be. (I'd suggest it be 41x41 for a unit that is 40x40, but maybe they have a reason for wanting it 40 1/2.)
At any rate, if you have 2x4 walls, use 2x4's... if you have 2x6 walls, use 2x6. Line it up exactly with the existing framing. If you end up needing some odd thickness to make the rough opening the right size, you can use OSB or plywood that is ripped down to the width of a 2x4/2x6. I would use construction adhesive between layers to prevent air infiltration.
Once you have the rough opening the correct size, you will cut some sheathing and apply it to the exterior of the rough opening. Whatever thickness sheathing is on there now is what you will use... OSB or plywood, doesn't matter.
Then you should apply some strips of building paper or felt around the opening. Apply a strip across the bottom, then strips down the sides. They will install the window on top of that building paper. Once it is installed, all 4 sides could be taped with window tape (Tyvek straightflash, Grace Vycor Plus, or similar) by taping the bottom first, then the sides, then the top. Building paper would then be applied over the top of the window, ensuring that the top of the building paper is tucked under any existing felt, if possible.
Insulate around the perimeter of the new window. You'll be able to put some strips of drywall around the interior framing you added then tape and finish that. Then you're new window will be ready to trim.
#3
10-13-06, 10:30 AM
Thanks XSleeper. That makes perfect sense. I was hoping to not mess with the old window frame, but I see how leaving it will interfere with trimming the new window after it is installed and I sure don't want to risk breaking it by trying to rip out the aluminum frame after installation, plus I need my weather-proofing in before and after window installation. Thanks again for clear instructions.
