Trim exterior windows half in concrete and half in wood/vinyl siding
#1
11-03-16, 10:34 AM
Trim exterior windows half in concrete and half in wood/vinyl siding
Hey,
Looking for some suggestions how to finish/trim this window that is set partially in concrete and partially in siding. The gap and in-set of the window varies around the entire thing and ranges from 1/2" to 1".
Thanks,
Chris
Looking for some suggestions how to finish/trim this window that is set partially in concrete and partially in siding. The gap and in-set of the window varies around the entire thing and ranges from 1/2" to 1".
Thanks,
Chris
#4
11-03-16, 10:58 AM
Group Moderator
Ok, clicking on the link worked.
Yikes, that's not really a very good way to install a window. A nailing fin is usually used to give you a surface to mount the window to (usually a wood buck that lines the masonry opening). Without it, it's just a leak waiting to happen. I also don't like that it's set into the wall, also creating a leak potential.
When a window with no nail fin is installed into a masonry opening, two things need to happen for it to work. It needs to be a "finished opening", meaning the bottom is sloped to drain water away from the window on the exterior... and all 4 sides are smooth, level and plumb, and are usually beveled back toward the face of the window so that the window can be slightly inset. None of those things appear to be true about your opening. THEN secondly, when the window has no fin, it is sized maybe a total of 1/4-1/2" smaller than the finished masonry opening so that once it has been shimmed and anchored, the perimeter can be filled with backer rod and caulk (a polyurethane sealant meant for concrete expansion joints).
Personally, I would recommend that you go back to the company that you got the window from and request some nailing fin... they should have something that you can snap into the groove around the window. (This means taking the window back out) That will enable you to mount the window on the surface of the concrete wall. You will caulk behind the nail fin (a very heavy bead of polyurethane sealant) before setting the window in place. The nail fin will act as a flashing so water doesn't come in around the window... especially on top and bottom.
When you go to reinstall the window, you will need to remove vinyl siding to get the nail fin under the siding and WRB on top. Your trim can then lay flat on the cement wall, with no "stops" or "jamb" needed to meet the face trim. The top piece of trim should have a drip cap over it and the top edge of the drip cap should be flashed behind your WRB. Then you will need new j-channel around the new trim... then you can cut your vinyl siding down to size and reinstall it.
Yikes, that's not really a very good way to install a window. A nailing fin is usually used to give you a surface to mount the window to (usually a wood buck that lines the masonry opening). Without it, it's just a leak waiting to happen. I also don't like that it's set into the wall, also creating a leak potential.
When a window with no nail fin is installed into a masonry opening, two things need to happen for it to work. It needs to be a "finished opening", meaning the bottom is sloped to drain water away from the window on the exterior... and all 4 sides are smooth, level and plumb, and are usually beveled back toward the face of the window so that the window can be slightly inset. None of those things appear to be true about your opening. THEN secondly, when the window has no fin, it is sized maybe a total of 1/4-1/2" smaller than the finished masonry opening so that once it has been shimmed and anchored, the perimeter can be filled with backer rod and caulk (a polyurethane sealant meant for concrete expansion joints).
Personally, I would recommend that you go back to the company that you got the window from and request some nailing fin... they should have something that you can snap into the groove around the window. (This means taking the window back out) That will enable you to mount the window on the surface of the concrete wall. You will caulk behind the nail fin (a very heavy bead of polyurethane sealant) before setting the window in place. The nail fin will act as a flashing so water doesn't come in around the window... especially on top and bottom.
When you go to reinstall the window, you will need to remove vinyl siding to get the nail fin under the siding and WRB on top. Your trim can then lay flat on the cement wall, with no "stops" or "jamb" needed to meet the face trim. The top piece of trim should have a drip cap over it and the top edge of the drip cap should be flashed behind your WRB. Then you will need new j-channel around the new trim... then you can cut your vinyl siding down to size and reinstall it.
#5
11-03-16, 06:04 PM
Thanks for all the info. It is appreciated.
Short of removing the window and reinstalling, how would you feel about using some self-adhessive flashing tape to bridge the gap from the window to the rough opening and the some 1*2 PVC trim or something similar around the perimeter of the window to go on top of/hide the flashing tape...
Thanks,
Chris
Short of removing the window and reinstalling, how would you feel about using some self-adhessive flashing tape to bridge the gap from the window to the rough opening and the some 1*2 PVC trim or something similar around the perimeter of the window to go on top of/hide the flashing tape...
Thanks,
Chris
