Concrete – How to consider when cutting/making window in concrete foundation

basementconcretefoundationwindows

I am thinking about putting in another window for my basement apartment.

I would like to know what do I need to consider before trying to find a contractor to do this.

I have uploaded a picture of the front and the side of my house.

Side View – Side window
enter image description here
Front View – Where I would like to add another window
enter image description here

It seems like in a lot of these windows that were cut in concrete the top left and the top right corner edges start to develop cracks. I have noticed that one of the windows on the side (See side view) has a crack going from top right corner edge to the top of cement foundation (crack length is about 4-5 inches). I already bought the house with the crack there so I did not see it develop, but could it be created when they were cutting the window out?
Anyway, if anyone else went through something similar I would love to hear from you.

Update:

Here is the side window crack:
enter image description here

Best Answer

I realize that you don't want to proceed with the project but I thought I'd answer anyway in case someone else is curious. I am a licensed contractor and my company specializes in basement remodeling; we have done several window expansions or additions in concrete foundations. A few things:

  1. You definitely need a permit for this project (though you don't need to hire a contractor) this is a structural modification and needs to be done correctly.
  2. You definitely need a structural engineer to write you a letter after a site inspection stating his recommendations for keeping the structural integrity (when you get a permit, they'll require this any way.
  3. If you are making a bedroom in the area you are adding a window to, you'll want to make sure that the new window you put in meets egress code for inspection/permit reasons.

Though you can support the new opening with pressure treated wood (according the engineers prescription, of course), most likely the engineer will recommend a steel frame in the newly cut opening. We use a 4"x4"x1/4" steel frame that the engineer signs off on. You can have one made to fit your opening at your local steel fabricator. (see pic below)

Steel Window Frame

After you install the frame with bolts into the concrete and silicone sealant around the entire perimeter, the installation of the window is a piece of cake.

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