# Any advice for making a glass block window?



## Mike Finley (Apr 28, 2004)

We've got an up coming project that we are going to have to create 3 glass block windows. The outside of the house is brick, the rough opennings all look to be 33 1/2 x 35 1/2. 

Glass blocks don't cut too well, them being basically 8"x8" I'm figuring roughly a 'window' of 32"x32". I'm figuring we are going to have to box these in. The inside isn't a problem as we will just drywall and trim them out to make them look good, but the outside is the issue. 

Any tips, things you have learned and a basic game plan to follow? I'm figuring banging these out for maybe $450 a window, wadda ya think?


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## dougchips (Apr 23, 2006)

Is there a reason for glass blocks or do they just not care if the windows open? If they are not set on having the blocks you could get an awning window with frosted glass made to any size. Or hell you could get a deadlite for small money.


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## Mike Finley (Apr 28, 2004)

They want glass block in the bathroom, and now since they have 3 windows on that side of the house, they want them all the same.

I'm guessing we will just need to frame the opening to fit within the old rough opening with something like Aztec.


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## dougchips (Apr 23, 2006)

If the 35 is your height, could you slant a sill from the front of the block so your "window" is square?


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## mickeyco (May 13, 2006)

I'm no expert, but I have put in quite few in a apartment building we have. Forget about framing it, look in the phone book for a company that makes glass block, they can make them to about any size you want (maybe a little thicker mortar joint around the outside) and there not to expensive. Do the glass blocks near the end when you know what the framed wall and tile size will be, usually you will have a little room to play with by moving the window toward the inside or outside so you don't end up with little slivers of tiles or large or un-even grout/caulk lines. Along those same lines push any imperfections in the wall to the outside where it's hardly noticeable. When I'm putting them in I use the mortar to also build up a slope on the windowsill so water won't puddle. To mortar them in I use shims 8 places until the initial mortar is dry, remove them and fill in the voids from the shims. The most important thing make sure it's secure until the mortar dries, the last one I did, someone slammed a door, the air pressure pushed the window out on to me who was standing on the ground below it, it burst a pile capillaries in my hands and broke into piles of pieces. Not done yet, I cleaned up the mess and I was carrying it to the trash a piece of the glass sticking out of the trash bag sliced my leg open requiring a pile of stitches, most expensive glass block I ever installed. I think I paid about $125 -$150 for the window pictured below about 5 years ago.


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## mickeyco (May 13, 2006)

One more thing, if you have them made up and you want all the blocks to be the same size tell them before hand, I got one once made with different size blocks.


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## Teetorbilt (Feb 12, 2004)

Don't cut the blocks unless you are prepared to put up with the 'condensation issues'. I cut them under duress but it costs a fortune. I have to do it because I work on block or cast homes most of the time. With frame construction it would be less expensive to change the size of the opening.


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## troubleseeker (Sep 24, 2006)

Buy a framed unit from your mill supplier or local window fabricator.


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## Greg Di (Mar 12, 2005)

Two routes:

1) prefabbed units of either glass or acrylic that come in a jamb sized to your rough opening

2) there was an article in JLC by John Carol within the last year with step by step on how to install a glass block window from scratch.

I've used the acrylic windows with much success. They install in minutes.


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## Mike Finley (Apr 28, 2004)

Having them made wasn't even on the radar, but it might be the smartest way to go.


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## skyhook (Mar 17, 2007)

double up or reinforce the framing to carry the extra weight.


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## Joasis (Mar 28, 2006)

I would be your Acme Brick showroom in Denver will have many on display. I have bought windows, and a shower wall unit from them...good stuff.


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## mickeyco (May 13, 2006)

I've got to ask (because I don't know), when I hear acrylic windows the first thing I think of is those acrylic tubs that scratch real easy. I've never used acrylic block windows, I can see the advantage of them being lighter, therefore an easier installation and maybe warmer (more efficient) than glass but I figure they have got to cost more. I'd also be worried about scratching because people tend to use whatever they're cleaning the tub with to clean the window (I'm assuming these are in a bathroom because Finley is doing them), ie. scouring pads or abrasive chemicals, I would think that even regular window cleaners would damage acrylic and they would eventually yellow. Like I said I have no experience with the acrylic block but I'd be curious to know about price and durability.

On the framing of the window, assuming there's a lintel and no wooden header, I would use none (glass bock to brick with a mortar joint). Why put wood that will rot between two surfaces that won't, they'll make the windows that will fit the openings without any framing, you can get the windows in an aluminum frame but it costs more and there's no need for it.

One more thing if the lintels are steel check for rot (beforehand), the job will get real expensive if you have to replace them.


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## dayspring (Mar 4, 2006)

I remodeled an upscale bath last year. We ordered pre-built glass block windows, worked excellent, installed just like a regular window unit. I've done glass block before and in my opinion, the units are the cats meow.


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## Mike Finley (Apr 28, 2004)

I just pulled an article out of Fine Homebuilding about Acyclic and glass blocks pros and cons and on Monday I will be calling around for some acyclic premade windows. 

All your suspicions are correct mickeyco with the exception of price.


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## woodmagman (Feb 17, 2007)

*Real glass*

Pittsburgh Corning makes a easy install kit for the glass block that can be siliconed in place rather then mortar. Real easy and Real glass......I have used it and very happy.


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## Mike Finley (Apr 28, 2004)

I've done many interior installations using block and silicone, but never for an exterior application. Something is nagging me making me think somewhere I saw something that said you have to use mortar for an exterior application, maybe it was only a recommendation, not sure.


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## woodmagman (Feb 17, 2007)

There are window companies that I know using the acylic block with silicone for exterior.
You could sub elasto-plastic chalking for the silicone. That is used to glaze glass on seal units (chalk glass to wood/metal/vinyl stops) It causes cancer in rats only in california, :whistling if I read the tube correctly, but works great for sealed units.......


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## Mr. D (Jun 7, 2006)

pre made unit would be the way to go.


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## Teetorbilt (Feb 12, 2004)

I wouldn't use sillycone for anything exterior. Interior, OK. Exterior, bad JuJu.


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## genbuilers (Dec 7, 2006)

I have done a couple of these also. I went to Home Depot and got them custom made.Worked like a charm.


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## genbuilers (Dec 7, 2006)

I did a couple of these. I went to HD and got them cusom made. Worked out great.


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