Greetings-
I need to redo some grout / mortar in my glass block window that is in my shower. It’s starting to fall out, both inside and outside. The existing stuff looks to be very course, like concrete.
What should I use and what’s the best way to apply? I have some thinset and I have unsanded grout leftovers from tile work I’ve done. Will either these work?
Kop
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Replies
Sanded grout would probably work, but I would buy glass block mortar from a masonry supplier. If you're in a large city there may be a specialty glass block supplier.
Kop
I don't think sanded grout is durable enough to withstand the constant exposure to moisture that glassblock windows will be exposed to.. I used a product specifically for glass block and it's differant than sanded grout..
So, it sounds like this probably can't be had at the homecenters.
home centers have it, glass block mortar.
Would it be applied using a grout float? Then just a real good cleanup?
Let me jump in with yes, use a grout float and clean up well, same as with tile. At least that is what I have done. I mainly wanted to tell you that thinset is absolutely not anything you want to use outdoors. The guy I work for a lot decided we, as in "I" should fill cracks in a driveway (hottest day of the year last year too, natch) with thinset. It probably almost lasted till winter. Anyway, by spring when we went there to do more work (lady never learns!) the thinset was a gray powder mixed with gray lumps partially filling the cracks.
that should work, also the bag will probably have instructions on how to use it.
Thanks all for the good info... I really appreciate it. I'll check at big box store & see what they have.
Must get back to work and get something done on this nice day - I'm sure you all know how it is..........
Kop
Kop
That's where I bought mine. Home Depot.
I used a very dry mortar mix. then when that was dry I gouted over it in the shower to match the tile...over a year ago.
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There is no grout per se in a standard glass block job; what you normally do is just lay the blocks up using glass-block mortar (either white or grey; depending on taste and application). Just like laying brick or concrete block.
However--for a shower where the joints will be right in yer face, only a foot or so from your eyeballs, striking the joints deep while setting the block and then filling them later with a sanded tile grout will give a much nicer job. The aggregate in glass-block mortar is just like the aggregate in brick mortar: coarse. The aggregate in sanded floor grout for ceramic is much finer, and produces a consequently finer finish.
There is absolutely no reason sanded tile grout can't be used on the walls in a glass-block shower. After all, it's what you use to grout the joints in the floor of a shower, and that really has to stand up to being wet.
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Above is a standard glass block mortar joint before striking. But below...
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...shows sanded tile grout used to fill the struck joints (after the mortar has dried, of course). And yes, you apply it with a stiff grout float, just like for a tile job.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
Dinosaur
excellant point!
The biggest danger in grouting a glass-block wall with sanded grout is scratching the glass with the sand while floating it in or buffing off the slop once it's dry. But just knowing you mustn't use too much muscle is enough to avoid any problem. Patience is the key.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Good point about the scratches. I did a storefront in Harlem and a music studio in Chelsea years ago, as well as a half dozen shower / baths, and the other thing I learned was to use a very dry mix when laying up the block, as there is no porosity to the glass, adn thus no moisture absorption as there would be for brick or CMU.Corning produced plastic spacers that get placed between the blocks and ensure consistent spacing in both axis. You then snap off the tabs later, much like form ties. They were rather expensive IIRC.
I don't remember the cost of those spacers, but for anyone except a bricklayer, doing a glass block wall without them would be a real dog's breakfast.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
If you don't do glass block all the time I would not do more than 2 or 3 courses a day. That is about all a duffer can set, level and clean without screwing some up.
I did a 5 course high bay window 5 wide plus corner blocks and a half size block to the wall. I did the first course one day, then 2 and 2. It came out great but these things seem pretty fragile until the mortar sets up
For a weekend warrior that sounds about right but for a competent remod guy who's not a stranger to levels and stringlines, four or five not-too-long courses of 8" block is more realistic.
The real limiting factor is the sag: if setting Thinline (3"-thick) block, the wall will want to sag sideways after about 3 or 4 courses, and must be braced plumb until the mortar sets up. With standard 4"-thick blocks, you should get another course or so before that happens.
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I've set a seven-foot-high 5'x3' shower surround in two lifts, and I don't consider myself a bricklayer by any stretch of the imagination. The mortar is easy to work with, being fairly fat, and those 3-D spacers really help. I wouldn't want to do it without them.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I've had a glass block wall in one of my showers for about 12 yrs now, and it still looks like new. I assembled the block with the white mortar supplied by the glass block supplier, raked it back 1/2", and filled the void with sanded tile grout to match the grout on the other (tiled) shower walls.
The glass block mortar I used was very fine - sounds like yours is just standard mortar. But if your wall is still solid, I'd just grind out the old mortar to a depth of about 1/2", and point with sanded grout.
Mike Hennessy
Pittsburgh, PA