Hey Folks,
My three year old glass block shower is driving me nuts with trying to seal up the base mortar joint where it rests on the marble sill. Water penetrates through the mortar joint and weeps through to the outside of the shower.
Numerous attempts at trying different caulks all fail as since it always gets wet, it only takes about a month or so until the bond of the caulk breaks. I dry it thoroughly each time before I try a different caulk and then let it cure about 4 or 5 days before use, but after a while, it still fails.
I’m considering trying clear aquarium sealant (no kidding!). But am open to any other suggestions as the mortar is getting very soft due to the water intrusion.
Any and all input is appreciated…Thanks
Mike
Replies
Anybody? Anybody?
OK, I know this isn't the most interesting of topics here but just bear with my shameless "bump".
Mike
I've had excellent results with clear silicone exterior door & window caulking. It seems to hold better than bathroom caulks I've used. I would not hesitate to try the aquarium sealant, or a similar marine caulk.
BTW, the mortar should not be getting soft either. You should try to rectify that problem before trying another caulk.
Good Luck.
Steve-o,
Thanks. The mortar just seemed to be getting soft from the repeat moisture but I also was concerned about it. Maybe "soft" isn't the right description but it does allow water to penetrate through it.
I'm thinking about drying it out, and re-pointing part of it with new glass block mortar and then recaulking with 3M Marine Sealant (or the clear aquarium selant I mentioned). I have seen a grout product at the tile distributor that claims is for underwater use like on swimming pools but no one I know can speak to its effectiveness?
Mike
If you can get that 3M Marine sealer to stick, you have probably solved your problem forever. Awesome stuff. Not sure how good it will look, and it does have a tendency to yellow slightly.
Glaziers use a proprietary slicone product. You might try looking for some or going to your local glass shop and asking. It is a much different product than standard sillycone caulks.
EricI Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
FB,
Thanks. I WAS concerned about looks but after redoing this a third time with a different caulk each time, looks are out the window. As long as it looks neat, I don't care about minor yellowing. But thanks for the warning.
Mike
I agree with using aquarium sealant. should work fine. Make sure that in addition to drying everything out thoroughly, you also rinse everything down liberally with denatured alcohol.
BTW, I know it's too late for you, but this is the reason why I would never use mortar for a glass block shower. I always use RTV silicone instead of mortar. Pitsburg corning has a silicone system that they sell which works pretty well.
Be aware that you may have created adhesion problems with the caulks you have already used that may be contributing to caulk failure. For example, it is difficult, if not impossible, to get caulk to adhere to silicon caulk that was laid down previously. Getting rid of ALL the silicon can be very difficult and time consuming as just scraping it off usually is not sufficient.
Formerly just 'Don' but not the 'Glassmaster Don' or the lower-case 'don'.
Guys,
First off thanks for the great replies. In the six years I've been hanging out here, I am never disappointed on the information others provide.
Here is my actual situation and I think I can adopt a little from each of your input.
The glass block is set directly on a marble sill. The grout and the marble were both sealed after initial installation. Water is indeed seeping through the base mortar joint and coming out on the other side, the exterior part of the shower glass block wall. I don't think its penetrating and coming "through" or under the marble as I've seen that happen before on other showers I've had to rebuild and the mortar and such under it showed signs of wetness.
To this point, I have removed all the old caulk and even used a grout saw to roughen up the joint and give it some bite. I may even repoint some parts of it to thicken the mortar and provide more of a "cove taper" to the joint to make it sloped even more to repel the water. I have plenty of time to let each phase dry as the house has two other showers to use so time is not an issue.
So the consensus might not be to use the 3M sealant huh? Would the aquarium sealant be a better choice or possibly the same glass block sealant made by Pittsburgh Corning that I used on the side joint of the glass block and the joint where the doors meet the block? It has yellowed slightly but still appears pretty water tight. I had initially steered away from using it for fear it might etch into the marble but now I'm not as concerned about that minor appearance flaw as I am the water leakage. I may have to check with my local glass house too as suggested.
So now I just have to decide on what sealant to use??? I have time to decide as by the time I dry it out completely and repoint, I think I can make up my mind. Thank again for your input guys. It really helps!
The only part that ticks me off about this is I've rebuilt about 20 showers in my lifetime with no call backs or problems and the one that has given problems had to be in my own home!!! URGH!
Mike
The 3m marine sealer that is being refered to is 3m 5200 or 4200. The 5200 is a permanent structural adhesive sealant. The 4200 is a non permanent sealant. Note the words "permanent" and "structural". I'm into the boat hobby and am quite familiar with both of these products. They are not silicones, but are actually eurethanes. These products are designed for use below the water line. The 5200's bond is absolutly incredible. It truly is almost impossible to remove. The peal strength is phenominal. Unfortinatly, it's sticks the best to gel coat and fiberglass. That said, I don't think it would be the perfect sealant for this application. I'm afraid that once again, you'll be facing a sealant failure. I believe that firebird was on the right track though. The highest performance sealants out there are the eurethanes. They bond very well, have great elasticity and are long lasting. Normally, I would spec a kitchen and bath silicone for it's mildew additives, but if that sealant has failed you in the past, then the eurethane will be your last choice. The surface must absolutly totally dry. The surface must be clean with a good tooth. I'd suggest washing the mortar with some bleach, rinsing, then washing again with a vineger solution (Don't let the vineger attack the sill). Now let it dry for a long, long time. The longer, the better. Then caulk the surface. You'll have to tool it. A masons concave tool or a spoon works well. It'll have to be wet or the caulk will stick and you'll have a holy mess on your hands. Some 3m adhesive remover will clean the excess off, so don't worry about it. Let the stuff cure overnight before cleaning it off. Now all of these chemicals will off gas something fierce, so good ventilation is a must!
I'd like to know if the sill is really the location of the water leak. Could the leak be coming from above, traveling down inside the wall and then first appearing at the sill? If this is the case, then the sealant will never hold as the water is forcing it's way out from behind.
Certified boat fetish.
Edited 1/24/2005 10:37 pm ET by Timbo
Hi mike, type in epoxymortar in your search engine. We're using this in a commercial ref. room under stainless. works well.
GB2.
Something else comes to mind, is the marble sill sloped and sealed? Marble is porous and can absorb and transport water under the mortar joint, wetting the mortar and delaminating the caulk.