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.

Here is the side window crack: enter image description here

  • How many stories is your house? Is the foundation showing a large pour of concrete (extending into the basement) or a veneer of mortar over block? Is the brick wall veneer or structural (double wye)?
    – HerrBag
    Apr 4, 2013 at 18:42
  • Can you provide better photos of the crack. It is possible that the crack has formed because there is a lack of a lintol over the opening to support the wall. If this is the case then creating the opening is likely to result in a number of issues.
    – Ian Turner
    Apr 5, 2013 at 13:30
  • @HerrBag The house is two stories. In my inspection report, it says the foundation is concrete. In your third questions are you asking if there is one later of brick or more? I am not sure about this and i cant find anything in inspection report either. Apr 7, 2013 at 0:18
  • @Ian Turner - I updated the original post. Apr 7, 2013 at 0:19
  • 5
    I wouldn't do this without an L shaped metal lintel on the inside to support the load above and also prevent crack/total failure of the veneer. My only thought would be to cut the hole for the window then immediately move to the interior of the home and cut a groove on the inside of this new window so that lintel can slide into the groove and support the very top of the window. The bottom of the window should be sloped outward as well to prevent rain from puddling outside the window too. Apr 17, 2013 at 5:05

2 Answers 2


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.


After talking to some contractors I have decided not to do this for the following reasons:

1) It would cost around $1400.
2) I might need permits to do this.
3) It might have an impact on the structure of the building.

Thank you all for your comments.

  • 2
    Sorry it didn't work out. Also if putting in a window I would do something larger enough to easily get out off during fire. If you really want to do this I would talk to a few contractors. Sometimes contractors overbid when they aren't experts in a particular area. Also putting in the windows the right way should not effect structure. There are tons of windows in concrete basements.
    – DMoore
    May 28, 2013 at 16:46

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