Replies

1. 
   Wayfarer | Feb 03, 2005 06:11am | #1

   I didn't do that exact application, but put in a glass block "wall" above a pony wall in my walk-in shower (and can attach a pic if interested) and at the time didn't even think of not using glass block mortar.  The only thing I will do is seal the mortar like the tile in the shower.  Maybe run a bead of caulk down at the bottom.

   
   

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   Edited 2/2/2005 10:11 pm ET by Wiley

2. 
   Woodbutcher | Feb 03, 2005 06:37am | #2

   I've done several showers built out of glass block.  I would never use mortar.  too much trouble with water wicking into the mortar and becoming a permanent mold & mildew problem not to mention it's just not waterproof.   I always use silicone.   Pittsburgh corning has a pretty good system that they sell. Check out their website

   I think it is http://www.pittsburghcorning.com

1. 
   CloudHidden | Feb 03, 2005 06:41am | #3

   The Pittsburgh Corning site gives instructions for mortar between the block and caulk between the starting edge and the wall.

1. 
   Woodbutcher | Feb 04, 2005 06:53am | #4

   Go to their website,  click on  "specs. & installation instructions"  then click on "quick & EZ installation system.

    I have only used their system once.  And then just devised my own methods and processes.  but it works pretty well, especially for a beginner, as they have pretty good instructions and tips.

1. 
   CloudHidden | Feb 04, 2005 07:35am | #5

   That's qualified as for "loose glass block" and the example shown is the block within a wall structure. The query here seems to be for a stand-alone shower wall, and the installation instructions for those seem to include mortar. I don't know if the silicone system would apply to a stand-alone shower wall or not--I'm not saying it doesn't--but they certainly intend that a mortar system is applicable for that use (also).

1. 
   Woodbutcher | Feb 05, 2005 05:10am | #6

   Cloud, I see your point.   I have built complete showers of glass block,  but the end wall (where the door is) needs something other than just the glass block itself to stiffen it up.   My preference is a 4" by 3/4" strip of cultured marble or solid surface, also attatched by silicone. 

   Perhaps Traini can give us more details regarding his particular project, such as height, width, will the end of the glass block wall be exposed?  stuff like that..... then we can give more detailed and (hopefully) better advice.

2. 
   donpapenburg | Feb 05, 2005 06:29am | #7

   Mark , How many showers have you built  useing the silicone?  What brand do you use?  The reason I am asking is the Pitsburg site states in the direction not to use silicone  in a shower . or I misread.  Any way I am going to build a glass block door for my shower. I have the frame done now . There is no way to stop the door from flexing and still have all glass block. My only option would be to have an attachment system that would flex also.

3. 
   Woodbutcher | Feb 08, 2005 04:22am | #16

   Don,   I must have misread your post.   Are you saying that you want to build a "door panel"  as in something that swings open and shut, out of glass block?  If that is the case, then I have no advice for you.  I can't see how you would ever get such a heavy, awkward thing to work.    I leave an opening in the shower enclosure and then have a frameless glass door installed.

4. 
   Woodbutcher | Feb 08, 2005 04:26am | #17

   Oh, one other thing, as far as what type of silicone I use.  Make sure you use the industrial grade RTV silicone (which, I believe, is what pittsburgh corning sells with their kit,  but don't quote me on that) .  A job like this is something you don't want to have to do  over.

5. 
   donpapenburg | Feb 26, 2005 09:13am | #18

   Hanging the  door frame was not the problem . The fact that it wiggles (the door) makes me think that I should use silicone to install the glassblock. Or it makes me wonder if mortar will make it stiff enough that it would not damage the bond . The door is a steel grid that the blocks will be fixed into .

6. 
   Woodbutcher | Feb 27, 2005 05:48pm | #19

   Well as I keep saying,  silicone will be waterproof,  mortar will act like a big ol' sponge.  Not to mention adding some extra needless weight to the door.

   I'm curious about how you're doing this,  can you post a picture?

7. 
   gdavis62 | Feb 27, 2005 07:35pm | #20

   I just re-read Dinosaur's post, the one with the pics, that described quite well the method he used in doing glass block work in a shower.

   He's using the glass block mortar, with all appropriate reinforcing and ties, to build and bond the wall together, but he is striking the mortar joints deeply.

   With the joints then deeply struck, he is grouting with unsanded grout, the typical grout method used for a shower wall and floor when surfaces are finished in tile or stone.

   He goes on further to say that the joints are then sealed with a liquid sealer product.

   So, how do his sealed grouted joints in his glass block wall, differ from grouted joints in a tiled shower?

   You wouldn't advocate grouting a tiled finish on shower floors and walls with silicone, would you?

   When you are doing tiled shower finish, what are you using to bond the tile to its substrate?  What are you using to grout?  How about your sealant product?

8. 
   UncleDunc | Feb 27, 2005 08:18pm | #22

   >> So, how do his sealed grouted joints in his glass block wall, differ from grouted joints
   >> in a tiled shower?The joinsts in the block wall are 4" deep, or more, whatever the thickness of the block is.>> You wouldn't advocate grouting a tiled finish on shower floors and walls with silicone, would you?If the tile were 4" thick, I'd certainly think about it.

9. 
   Woodbutcher | Feb 27, 2005 08:45pm | #23

   Ok.

   Here is where I will make lot's of enemies and basically get flamed completely off the boards altogether.

   I have never seen a tiled shower or tub surround that didn't eventually get water behind it and turn into a nasty, leaking, mess,  never.   I personally would never use tile in an application that is designed to be waterproof, because even if you do seal all of the grout joints, that thin little bit of sealer will eventually crack and the water infiltration will begin. 

    My theory is to use only solid surface materials, whether it be cultured marble, or wilsonart gilbralter, or Corian.  Something in a sheet form that can be sealed with urethane caulk and will not have a gazzillion little potential leaks in the form of grout joints.

     Ok... there... I said it...  Let the flamin' begin... 

10. 
    donpapenburg | Feb 27, 2005 08:17pm | #21

    Mark,I tried but the attach files button does not work.

    Anyway it is a door for a curved wall . It is made of  steel ,in a grid 8x8 exept for the center block that are 4x8 , the ends are open for end blocks. The top mand bottom ribs are made with1 1/ 2" thick steel . The rest of the ribs are made of 1/4"   A 1" shaft come out the top rib to insert into pillow blocks and on the bottom is a cup to hold a cone and tapered roller bearing. All that sits on an adjustable spindle in the floor.

    I think that I might try Srurdi flex thinset to hold the tile to the frame work .  That might make the door stiff enough that it does not flex or twist . On the other hand I was thinking that the silicone would flex enough and still stay bonded . One of these days I will have to decide . In the mean I will hash it out with any one who has some understanding of grout ,masonry,tile , GB,or shower doors.

    I don't think that the mortar would add more than 5-7 lb. to the door . Not a significant amount considering the glass block makes up the vast amount of the door.

2. 
   LisaWL | Feb 05, 2005 09:18pm | #10

   Timely discussion - we're doing an addition with a "walk in" shower (no door) with one glass block wall extending out from the tiled wall.The Pittsburgh Corning site recommends the 4" thick block for shower walls, and says you must use mortar installation for 4". In the FAQ for Mortar One and Mortar Two installation, it says:"Do I have to caulk the mortar joints if I'm using glass block in a shower wall or high moisture area?""After you have completed the installation, struck the joints smooth, and waited a week or two, coat the mortar joints with some type of clear acrylic or silicone type sealer for mold and mildew protection.""A completed home is a listed home."

3. 
   WorkshopJon | Feb 05, 2005 02:22pm | #8

   Traini,

   I've built shower walls using mortar.  Properly sealed IMO doing it that way is the ONLY way to do it.  I would think that using silicone to "glue" the entire thing together would make for a less than solid wall and a sticky mess during construction.

     Pittsburgh Corning does recommend sealing the outer perimeter of the wall with silicone, but if the shower is stable, and you embed heavy angle brackets in the mortar and bolt them to the wall, you can mortar that right up to the tile. Makes for a much neater installation.  They also have instructions for doing this online

   http://www.pittsburghcorning.com/builders/specdetails.asp

   click on the link Mortar I & II method.

   The two hardest parts of building walls like those is keeping them planer (flat, level and plumb) during construction, and getting used to mixing and working with a very dry mortar mix.

   WSJ

4. 
   DANL | Feb 05, 2005 06:15pm | #9

   I have only put in "windows" using glass block, but after having a heck of a time with the first of the last two I did (mortar kept sqeezing out and so on and I was using little pebbles to hold the blocks apart) when I went back to the store, I noticed all sorts of things that help space and hold the blocks while you mortar. There are even strips of like sill seal to insulate between them and then you just run a bead of mortar on inside and outside lips of the block.

5. 
   Dinosaur | Feb 06, 2005 02:29am | #11

   Here is a photo of a glass-block shower which I built last year for a client.

   View Image

   If you want to see the whole thing, check out this thread: http://forums.taunton.com/tp-breaktime/messages?msg=46974.1

   You are looking at using mortar on your job. Forget about silicone; the system you need is Pgh/Corning's 'Mortar II' system, which is described on their website. All the materials should be available from the yard selling you the blocks.

   Basically, this system uses 3-dimensional plastic spacers (similar to tile +'s but with a tie-rod connecting two of them); metal anchor strips bent into L shapes (these are screwed to a structural side-wall and set into the mortar between each 2nd row of blocks, and also across the top row, anchored to joists or furring); you also insert miniature re-bar ladders between each 2nd row of blocks; finally there are expansion strips of what looks very much like white Sill-Seal which close the gap you must leave between the block wall and the wood framing to allow the glass block room to expand and contract with temperature changes.

   Glass-block or 'white' mortar is a very fat mortar that is relatively easy to work with. You don't want to mix it too dry. I mix mine somewhat drier than thinset;  I don't want it to droop but I don't want to have to use tons of muscle to put it where it has to go, either. Here's what it looks like:

   View Image

   To finish the joints, strike them quite deeply when you lay the block and wire-brush them clean (by hand!) after the mortar is dry. Then apply a sanded floor grout the same way you would on a tile job. The aggregate in sanded grout is much finer than that in the mortar, and especially in a shower installation where the client will be staring at the block wall from less than 2 feet away, the improvement in appearance is quite noticeable.

   Pittsburgh-Corning has excellent tech support via their 800-line and lots of info on the website.

   No long-term problems that I'm aware of. Just make sure the client understands he can't drill into a glass block and hang his toilet-paper roll from plastic anchors stuck in the holes, LOL....

    

   Dinosaur

   'Y-a-tu de la justice dans ce maudit monde?

    

1. 
   BillBrennen | Feb 06, 2005 03:34am | #12

   Dino,That client could drill holes in a horizontal joint and hang his toilet roll holder on that, couldn't he? I may do a curved glass block wall in my own (small) master bathroom, and the toilet will be next to it. I figured you would know.Thanks, Bill

1. 
   Dinosaur | Feb 06, 2005 06:36am | #13

   Yeah, I suppose it could be done that way. Main thing would be not to pierce or crack the block in any way. They're manufactured in a controlled atmosphere environment (very dry) with a partial vaccuum in them to prevent fogging and condensation and the second you let any ambient air in, that block has had it. After a while they start growing black, nasty mould inside.

   Personally, I'd try almost anything else rather than mount something on the face of a glass block wall, if for no other reason than the æsthetics. I mean, why spend all that money and effort to put in glass block and then start covering it up with stuff? I've seen some fairly nice-looking TP-roll floor stands made of brass that could solve a 'where-to-hang-it?' problem fairly well.

   The fact you can't cut glass block makes obvious that your design phase has got to be spot on; you won't be able to 'trim it to fit' so you have to design the wall based on the sizes of block available. For instance, in the job I posted, I had to build and tile a curb wall on the bathroom floor to start off the glass block so that it would rise just through the ceiling...but not hit the I-joists above (which can't be notched either!). Heavy built-up cornice moulding hid that joint and 15/16 cove hid the silicone caulk I used to seal the expansion joints where the glass block joined the side wall and the door jamb.

   If you're thinking about a curved block wall, be aware that while the standard 8x8 blocks are not horribly expensive, all specialty blocks such as corners, ends, and curves are. IIRC, the standard blocks I used in that job cost in the neighborhood of 7-8 bucks a pop, while the corner blocks cost something like $30 each.Dinosaur

   'Y-a-tu de la justice dans ce maudit monde?

    

1. 
   traini | Feb 06, 2005 07:58am | #14

   Thank you for all the good info

   On this job the glass blocks will sit on a small knee wall high enough to cover the end of the standard tub. I assume form your info that where the glass blocks meet the interor wall covered with concrete board  and tiles,I should anchor with available ties but use a foam strip to allow for expansion between the glass blocks and the wall.  The base of the tiles will be sitting on  the knee wall covered with concrete board and tiles I guess I should also tie with masonry type anchors but without the foam???

   Thank you again for the pictures and ifo.

   George

1. 
   Dinosaur | Feb 06, 2005 08:35am | #15

   You don't need to place panel anchors (that's what Pgh-Corning calls them) into the first course vertically up from the foundation. They would normally be placed horizontally into the space between the 2nd and 3rd courses of block and so on up, every second course. They are bent into an L with a short and long leg. The long leg is laid into the mortar on top of a block and the short leg is screwed to the wall or framing. The expansion strips are cut to fit vertically between the panel anchors. I don't know if you would need them on a wall that's free-standing on one end (which seems to be what you're describing).

   To lay your first course on top of a tiled knee wall, scratch the tile with some 40-grit paper in an RO sander, then paint it with Weld-Bond thinned out 10% with water. Let that get tacky before you start setting your block on top of it. It seems to me this is the method you'll need to use to join the block to the tiled wall behind the tub, too. Check that with P-C's tech people, though; I haven't done one like that myself.

   In addition to anchors on the vertical framing going horizontally into the block courses, you need to anchor the top course of block vertically to the overhead, by inserting a panel anchor between every second column in the top course of block and screwing it to something solid above the wall.Dinosaur

   'Y-a-tu de la justice dans ce maudit monde?