Basement Window Replacement

Old 08-14-06, 08:45 AM
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Basement Window Replacement


I'm planning on replacing my basement windows however I'd like to cut larger ones in than existing. The existing windows are approx 30"x12", pretty small and in very bad condition. I went to home depot yesterday and they stock 30"x36" windows which would allow much more light in to our basemet. The question i have is is there a problem with installing the window close to the outside of the foundation rather than the inside as they are typically installed when new?
Old 08-14-06, 04:46 PM
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Yes, the problem would be the appearance of the window from a distance, and possibly flashing the bottom of the opening. Often, the old windows were centered in the block wall, and a mortar bed was laid into the bottom of the opening to create a sloped sill on the interior and exterior sides of the window. If you install the window to the exterior of the wall, you would want to recess it perhaps 3/8" so that a large bead of polyurethane caulking (one that adheres well to cement) could be run around the perimeter of the opening to seal it.

Your windows could be installed in one of two ways:

1). Replacement window (no nailing fin) custom sized to fit the masonry opening.

-if your finished masonry opening is 30 1/4 x 36 1/4, a 30 x 36 window would fit nicely.

2). New Construction window (with nailing fin) custom sized to fit a masonry opening that has been lined with a pressure treated woodbuck.

-your rough masonry opening would need a PT 2x8 or similar anchored (and sealed to the cement with sealant) into the opening which would provide a surface for the window (with nailing fin) to be nailed to. This type of installation would mean the window would actually be sticking out past the surface of the wall by 1 1/4" or so. The nailing fin would also need to be covered with some exterior trim.

If you decided to install the windows in the middle of the wall, like your current ones are probably installed, you would install using the first method, but would install the window in the center of the wall. When measuring for your window you would want to make the window approximately 1 1/2" shorter than usual so that the window could be shimmed to the top of the opening and so that a sloped cement cap could be poured along the bottom of the masonry opening after the window is installed.
Old 07-18-08, 06:26 AM
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My Dilemma - Old Basement Window

Hi. I'm new here so I apologize if I'm posting in the wrong location. Here's my story: I removed a very old wooden basement window (the frame was rotted). I have a vinyl window that I picked up at an auction for a great price that goes vertically but I am going to use it horizontally. The house is stucco. The opening for the window is larger than the window itself. I was able to chip out enough of the old stucco and stone to temporarily put the new window in. Looking at the window from the outside, I have it butted up against the right side of the stucco wall. This leaves an opening that a PT 4x4 might fit. Here are my questions:

1. Can I or do I use PT lumber around the bottom of the window and in between the window and the stucco?

2. Can I use spray foam to seal the window from the inside?

3. Do I use stucco patch or can I use just regular concrete to patch over the PT lumber/frame?

4. Any other things that I need to do to complete the installation?

Any other suggestions would be greatly, greatly appreciated. My wife has been eyeing up the tent as of late so I guess that means I need to get this project finished!

Old 07-18-08, 01:10 PM
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Hi Doug, welcome!

Usually when you have a question, it's best if you start your own thread by going to the appropriate forum (such as doors and windows) and then click on the "new post" icon. It works better than clicking reply and adding your question into someone else's thread.

First off, I would not recommend that you turn your window on its side. If this is going into a garage or shed or something, then maybe it would not be a big deal. But the reason you should not do it is that vertical windows have "weep holes" on the bottom. When it rains and water gets into the bottom track of the window, it weeps out the weep holes. If you turn the window on its side, there will be no weep holes and it's very likely that when it rains, you will get water inside the home. So I would not recommend that you use this window.

Having said that, it isn't quite clear for your question what type of a rough opening you have. Since you mention stone, I'm assuming that maybe you have a cement/stone foundation. The first thing that needs to happen is that you have to have slope on the sill of the window, and it has to be level. On a cement opening, this might mean that you will have to parge concrete onto the existing opening so as to make it level. If it is already prepared, then you would go on to the next step, making the rough opening the correct size.

You could use PT wood and anchor it onto the sides of the rough opening. You'd remove the window and it usually works best to anchor an equal amount of wood onto each side... such as adding a PT 2x4 onto both sides, rather than adding a 4x4 onto one side. This keeps the window centered in the opening. For advice on stucco, I'd ask for opinions in the masonry forum, unless someone happens to know here. I don't mess with stucco. Another option is to apply some exterior trim over the PT that would cover it and the cut edge of your stucco. You'd need to seal it well to avoid leaks. I'm not a big fan of using caulk to seal out water though.

You can use spray foam around vinyl windows, but if you do, be sure you use foam that specifically says that it is "low expansion" or for "windows and doors". Great Stuff in the red can is BAD, Great Stuff in the blue can is okay. For gaps 1/4" or less, Dap latex foam works well. Whatever foam you use, use it sparingly, and apply it cautiously because it comes out faster than you think and expands more than you think. If you get it on the window it often won't come clean.

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