I would like to build an egress window in my basement as there is currently only one way out and that is right next to the furnace. It doesn't seem like it would be too difficult as the material is readily available. The one thing I can't figure out is how to cut a straight line through the cement block for the opening. Is there a saws-all that cuts through cement? Any ideas? Rich
Do a little research. Maybe call a rental center...
Good luck
- jbd in Denver
RJDurkee wrote:
Yes, there are abrasive blades and diamond tipped blades. If you have a lot to cut, it may make sense to have a pro do it. Some will give you a price on the phone if you give them the thickness and size to cut. Not cheap, but perfect cuts.
A perfect cut is nearly impossible in concrete block walls because the block is hollow leaving holes you can't fasten bucks or windows to. Just break out the entire blocks and lay in new corner(smooth ended) and cap (smooth top) block cut to size with a diamond blade or abrasive blade in a throw away skill saw. Don't forget to look at the head of the window to determine if a lintel or header is needed to carry the load from above. It doesn't take much weight on top of the window to break it.
I put down some Bluestone and bought a diamond blade to cut them. Later I needed to cut some 8" block and the thing goes through them like butter - well almost. Mine is a Continuous Rim blade and I paid about $60 for it.
I've cut concrete and terracotta that way also but it kills the saw. Abrasive dust quickly erodes the bearings and commutator. If you have an old saw that deserves to be tossed anyhow, go for it, but don't risk a nice saw.
I agree with others, the diamond continous rimmed blades work well. I've got one for the 4.5" angle grinder, and worm drive saw...and both work extremely well. And yes it's hard on the grinder and/or saw. I've probably cut as much concrete as wood with the saw...and now it's a dedicated concrete cutter. I don't know how the blades work with a traditional saw. Another tool that works VERY well, and doesn't cost much money is the little pneumatic air hammer, the flat bit smooths up the cuts and the pointed one removes material very quickly. It acts like a mini-jackhammer.
When making your rough opening...depending on the size of the window and it's desired placement, try to stay away from the middle webs, and ends of the block, it's much thicker there. Don't forget, cement block chips easily with a 3 pound hammer, so you don't have to cut it all, concrete chisles work well. By the way, give yourself at least an additional inch on the block side of your rough opening mateial...don't make it too tight otherwise you'll be fighting the framing material when squaring up. Great stuff seals any large non-structural gaps nicely.
Don't worry if there's reinforcing metal webbing, the saw blades zip right through them.
The first window I installed, I used the chainsaw type concrete saw...man that baby stinks up the house and just about kills the operator outside in the hole, not recommened, overkill.
By the way, one last thought, I would stay away from the item called scape-well, it's a plastic surround, that bolts to the exteior basement wall. not a very well built product. I use PT material and the seem to hold up well, with backfilled with large stone.
A couple of other thoughts, make sure you wear adequate air masks, safety glasses and use lots of fans to make sure you control the dust. I have on occasion sledged out a medium sizied hole in the block where the window will go, and wired a regular window fan into the hole which helps pull the dust out.
Good luck.... DAC
Doh!
Thanks for taking the effort to save my nice Milwaukee saw!
Very much appreciated!
- jbd > JBD >> I've used a circular saw with a masonry blade on a basement floor. >
Most rental centers have concrete saws for that job- and that is really the way to go. But that's a kind of a nasty job you've got in mind there, lots of noise and dust- and then you have to worry about making sure it's sealed properly once you've got it done. If you haven't thought of it, there are pull-down stairs that will go between two floor joists with some minimal framing and cutting for an emergency exit.
There might be a reason why you prefer the window option, but the stairs are a reasonable alternative if you concern is mainly about having a second exit- I know for myself, I'd rather mess with the foundation of my house as little as humanly possible.
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