# Glass Block



## Paulie (Feb 11, 2009)

Installed glass block wall in a bathroom. Used white silicone for grout lines. Looked good. Then put the vanity light up, about 3" away from wall (small bathroom). Looked terrible. Light showed every little fudge. Tried to go over top with more white silicone, looked worse. First; anybody got a trick to get silicone out of glass block grout lines? Second; is there a unsanded grout recomended for glass block?


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## Paulie (Feb 11, 2009)

nobody has any idea's huh?


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## Mike Finley (Apr 28, 2004)

It's a silicone installation, that is supposed to be what it looks like (silicone DIY, not Mortar Pro results).

I don't think you can remove the silicone and substitute grout now... isn't the silicone installation totally different installation method and you need that silicone in there to hold it together?

The only thing I think you can do if you are determined to remove it and replace it is to go to an acrylic based caulk such as the ones in the tile industry and use that, since it is water soluable you will be able to tool it with a wet spong and get better results.


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## Paulie (Feb 11, 2009)

Yeah its a silicone install with the dividers ancored into the opposing walls. There is plenty of silicone between the blocks for structure its just the grout lines for show that look VERY bad. The thing is I've done a bunch of glass block in basements and such and there has never been a light that shines up against them. I'm hear to tell ya it shows and magnifies EVERYTHING! I have done the latex caulk trick before but I've already got 2 coats of silicone in the grout space. There's got to be a grout for glass block right?


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## Mike Finley (Apr 28, 2004)

What would be the difference between a grout for glass block or the acrylic based caulk?

If you're saying the structure is sound what you want is just for looks now.


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## Paulie (Feb 11, 2009)

The reason I was thinking grout is the method of letting it dry and set up then wiping off the extra. The grout in the joints is hard enough so your sponge won't leave marks. Caulk dries from exposed surface down, it has a skin at first then hardens up. If the caulk is wet enough to wipe away it leaves marks were the sponge took too much or to little. I know what you're saying though and if it wasn't lit up by that bright ass light shining down the rows it would be what I would do too.


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## skyhook (Mar 17, 2007)

If it looks bad with a bright light on it, turn the light off. :thumbsup:


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## Paulie (Feb 11, 2009)

Too late the HO already called me on it. I agree with ya, whenever my motor starts knocking I turn up the car stereo, engine sounds just fine after that. Seriously though, there has to be a grout for glass block.


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## Mike Finley (Apr 28, 2004)

paulie said:


> Seriously though, there has to be a grout for glass block.


It's called mortar. 

Or just use regular sanded tile grout. When we do a shower with glass block and we want the mortar lines of the glass block to match the tile grout we mortar the glass blocks in place and leave the lines between them dry then use the same sanded grout for the tile in the lines of the glass block.


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## Paulie (Feb 11, 2009)

Thanx Mike I've used the mortar to. I specified unsanded grout on my first post because the HO wanted it too look like the other side(shower side) that has white silicone and looks fine. I also was worried about the silicone already in the joints.


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## jarvis design (May 6, 2008)

Grouting over silicone is not a great idea - even if you cut out the majority of the silicone, I would think it would be hard to get all the residue off. 
As for grouting glass block, what size spacing is between the blocks??
If it is a 1/4" - unsanded grout will not work - too big of a space.

I have done lots of glass block - have always used glass block mortar - blended with some additive - will normally "grout" the lines after the panel is built ( with grout float/sponge)


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## Paulie (Feb 11, 2009)

Thanx for the reply, I know about the silicone, it really doesn't sound like a good idea to me either. I have had 2 tries at making the silicone work and thats it for me. I wish I would have taken a pic, I have to go over there for additional work, I'll try to remember the damn camera weds. I'm telling you it looks like my first drywall job. 

So what you are suggesting is first mortar the joint, then go over top with grout? Hmm.

by the way the blocks are stacked on a guide and the edges are touching.


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## jarvis design (May 6, 2008)

paulie said:


> Thanx for the reply, I know about the silicone, it really doesn't sound like a good idea to me either. I have had 2 tries at making the silicone work and thats it for me. I wish I would have taken a pic, I have to go over there for additional work, I'll try to remember the damn camera weds. I'm telling you it looks like my first drywall job.
> 
> So what you are suggesting is first mortar the joint, then go over top with grout? Hmm.
> 
> by the way the blocks are stacked on a guide and the edges are touching.


When I say "grout", its just my term for finishing the joints vs. striking as in masonry. - Its all done at the time of building the panel, although I have seen jobs where the panel was built and the mortar was actually removed (about a 1/4-3/8" deep) and then grouted with a sanded tile grout after the mortar had set.

However, if the block edges are touching, I think you can forget any kind of grouting - you need some sort of a grout space.


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## Paulie (Feb 11, 2009)

hey, I was just at that job today and removed most of the old silicone. I didn't have much of a chance to work it though, HO has me repairing downstairs lath and plaster (extra's). Got a couple of pics of my screwed up job on the silicone. Although I will keep my system of stacking them with track and silicone I will grout them in with mortar. 

Even though they are touching there is still a grout line due to the bevel of the block. Tried to upload 2 pic's.


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## Mike Finley (Apr 28, 2004)

Looks good in pictures!


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## Paulie (Feb 11, 2009)

I don't know what the hell happend to the one pic but it really is noticeable in that one. Oh well.


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## Nobreus (Feb 22, 2009)

Paulie, i have a bid in process of taking apart a glassblock wall surrounding a shower. The wall is about ten feet long and eight feet high, and the two reasons to take it apart are that the HO wants silicone joints instead of mortar joints, and that the wall has bowed. i am afraid that this will turn into one of those nightmare jobs that ends up costing me bunches, but i have done my research on cleaning the blocks with muriatic acid, and the connection systems for silicone, but i still think that the mortar seems like a better, stronger way to go, what do you think?


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## Paulie (Feb 11, 2009)

Probably should start a new thread. 

First, a shower wall 10' long?  Yikes! I agree mortar has got to be stronger and a better material.

Second, I guess I want to know why it failed in the first place. Was it reinforced in the first place? I doubt it.

To be honest I don't remember doing a 10' long, 8' high glass block wall, in my days, I usually do the 5' shower wall's or window's. Maybe theirs another that can help with the experience.


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## platinumLLC (Nov 18, 2008)

I have used both the silcone and the mortar method to glass block walls and I will tell you that I will not use the silicone system unless it is a small glass window fully supported on all 4 sides. I tried to use silicone on a wall that was 3' wide by 5' tall and supported on the bottom, one side and the top. Used the wall ties to tie it into the wall for strength and it was really weak and I didn't feel comfortable leaving something that had the potential to come down if someone leaned on it. An 8'x10' wall I would not even think about using the silicone method, you will want to use the mortar so if someone leans on the middle of the wall it won't bust out.


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## Driftwood (Feb 15, 2004)

Years ago We did hundreds of Pittsburg corning Blocks. Always mortar.
400 for a bowling alley once. I,ve seen people screw them up often!
Some fun, On a wet saw. I cut the tops off at about a 16 degree angle .
Nice for flowers,sea shells ect. With a glass drill You can drill a hole and put white Xmass lites in. Nice nite lite for a child.


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## jarvis design (May 6, 2008)

A little off topic, but, a number of years ago I was doing design consulting for a client who was adding a small addition onto their cottage (2000 sq ft)

The architech specs in a glass block window about 4' and 6' and further specs that it be a double glass block window with 1/2" air space in between.

Stupid architect!!


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## skyhook (Mar 17, 2007)

Keep this up long enough and a real glass block artist might chime in.
As for me and what I know, I am keeping it a secret. (where is that flip off emot) :laughing:


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## Driftwood (Feb 15, 2004)

Most bring experience to the table. Those empty handed, bring sarcasm.


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## gallerytungsten (Jul 5, 2007)

skyhook said:


> Keep this up long enough and a real glass block artist might chime in.
> As for me and what I know, I am keeping it a secret. (where is that flip off emot) :laughing:


Well, here is a "secret" for glass block. If you read Pittsburgh Corning's documentation for the mortar method, they say to make your rough opening 1/2" larger in both dimensions than the nominal size. So, if you were using 8" block and had a window that was 8x8, you'd have 64.5x64.5 for your rough opening. 

However, they're wrong. In actuality, you want 1/4" extra on the width and 3/4" extra on the height. This will give you a nice snug fit on the width, and leave you a little extra margin on the top, which is very handy for getting that last row in. (This assumes you are of course using the 1/4" spacers.)


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## skyhook (Mar 17, 2007)

Driftwood said:


> Most bring experience to the table. Those empty handed, bring sarcasm.


When people are talking about building glass block walls with silicone instead of GB mortar, I bring empty handed sarcasm. :jester:


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## Driftwood (Feb 15, 2004)

*Thanks here's another*

The most common mistake. Mixing motor too wet! Glass doesn't absorb water 
like concrete block! Mix it dry,don't run too high! Iallways Made My own wood ,temp. spacers, to keep the bond honest.


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## Driftwood (Feb 15, 2004)

skyhook said:


> When people are talking about building glass block walls with silicone instead of GB mortar, I bring empty handed sarcasm. :jester:


 Sorr now I get it ! silicone is a joke!


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## greg24k (May 19, 2007)

I have been using glass block windows, shower enclosures,partitions,etc for all my new construction and remodeling projects,and HO love it. The product is made by Hi Lite Manufacturer 

If anyone interested ot have a project coming up, something to consider.

Good luck :thumbsup:


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