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andrewcocke 02-23-2008 08:25 PM

Want to install larger window in basement wall
For ages now I have wanted basement windows that actually let in a decent amount of light and that you could open.

Currently, the windows I have installed are the older type, two pane. Once upon a time, it looks like they opened, however from the looks of it, for the last 30 years they have been painted and caulked shut.

My house sits on a slope and I have a walk out basement. So the foundation on the back side of the house is completely exposed. I have two windows that I want to remove and install windows of equal width, but about three times as tall. From the looks of it, I would need to remove the concrete sill under the existing window which is about 9" thick, and remove two layers of block under that.

I have thought about it and I can't see any reason why it would place a strain on the foundation or the walls above, as the current window is right under the sill plate. In other words, the sill plate just runs right over the window, there is no metal or block above it. I cant see why removing 2 1/2 feet of block below the window in order to install a larger window would hurt anything.


If you agree, then lets move on to the best way to do it. I have a concrete cutting blade for my circular saw, I figured I could just make 2 vertical cuts on both sides of the wall, and use a sledge hammer to remove the part of the wall I want removed, then just frame in the new window.

Would this be the best way?

concretemasonry 02-23-2008 09:14 PM

As long as the opening is not wider on an exposed walk-out, it sounds like a good plan.

just make sure you have a good plan to install the new windows you buy.

andrewcocke 02-23-2008 09:29 PM

That's what I figured, but I just thought I would ask.

I plan on starting this in the next few weeks. I have installed replacement windows in a basement before, this would just be the first time I have enlarged the rough in.

It just gets so stuffy down there in the summer, I thought it would be "cool" to be able to open a window and let some air in.

Chris Johnson 02-24-2008 12:13 AM

Assuming it is an 8" wall, cutting with a circular saw is not a good idea, even cutting from both sides. To do the job right hire a concrete cutting company and let them do the work for you, may cost a few bucks, but they have proper equipment and can cut the whole thing in one sweep from the exterior.

LawnGuyLandSparky 02-24-2008 08:30 AM

And while you're at it- just widen the openings enough to accomodate a nice, generous 34-36" wide window. If it requires a header, so be it. No sense in going through all this work to end up with super narrow windows that happen to be tall. That look went out in the 80's.

Also while you're at it might as well throw in a door, make it a real walk-out basement.

This way, 20 years from now, someone who buys your house won't be posting here "I bought a house with a kind of walk out basement. I want to make a bedroom, but when the original HO made the windows taller, he didn't make them wide enough to be legal egress windows. Now I have to do it all over...."

terri_and_jj 02-24-2008 08:52 AM

is the wall block or poured concrete? If it's block you might be able to get away with the concrete blade on circ saw. I would follow with a good masonry chisel before just whacking with a sledge though. Either way the removal might be a little more involved as there SHOULD be rebar running vertically. Be prepared to cut some out. if you don't want to incur the expense of having someone else cut for you, it might be worth renting a real concrete saw for a couple hours

andrewcocke 02-24-2008 12:50 PM

2 Attachment(s)
Although I really don't know about the rebar, something tells me there is no rebar in side the block. In any event I can get to blocks I want to remove loosened chip the out and take a sawsall and cut the rebar if need be.

I was looking at windows today. There is another window on the other side of the house I'd like to at least replace, but I'd have to just put in the same side window as it comes down to the ground, this would require a custom window I have no doubt.

As far as my plans go, I had wanted to make a room down there, not a bedroom, just a plain room with walls and a ceiling to hold heat so I can have a "mans pad". Complete with a futon, TV set, mini fridge and a place to set up model trains.

The second window about 20 feet to the right I am just installing so it evens out and I don't have two different windows.

As stated earlier about half of this basement is not underground so it doesn't stay that constant 60 degrees down there. In the summer it can get hot and sticky down there, I run a dehumidifier, but it'd be cool to be able to actually open a window and get some cross circulation.

On the walk out door I have already installed a simple screened door so I can open it without letting dogs and critters in.

In the pictures below, the lines indicate where I want to make my cuts.
The blue line is the mortar line.

andrewcocke 02-24-2008 12:59 PM

Oh, the dimensions I looked at are 30" wide by about 40" long.

When I took the picture of the outside wall I noticed that as it stands the basement window already looks to be slightly wider than the window above it. Come to think of it, the windows upstairs must be 28" because I know we have to buy 27" blinds for them.

Ron6519 02-24-2008 10:51 PM

You can rent a 14" bladed concrete saw that will make short, neat work of the opening. Should cost about $50.00 for 4 hours.

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