Recomended Caulking

I have an IG concrete pool. There is currently caulking between the ceramic tile (the tile at the water line) and the coping (I've seen it called decking and top cap). At any rate, the caulking needs to be replaced. This area is always wet when the pool is in use, but rarely is completed submerged. The gap is approximately 1/2" wide. I'm assuming the existing caulk should be replaced with an equivalent caulking. Anyone have any recommendations on what type, what works best? Thanks in advance for your responce and help.

Scott

Hi, Scott

Wow, that's a pretty big gap for caulk. Is it vertical or horizontal? I'm assuming it's vertical since it seems to touch the waterline tile.

Well, without seeing it (can you post a pic) I've always felt polyurethane caulk was the most durable for pool areas.

I am a little concerned that poly may "sag" a little while curing on that vertical plane. Worse, I can think of no way to prevent it. Silicone sags less but I dont think it's long-term characteristics are as good as poly.

Give us a little more info. Confirm the vertical plane. Post a pic if you can. Perhaps some of the pros will be along soon and will have experience filling that large gap....it's a little larger than I'm accustomed to and I'm not confident in my advice.

Dave S.

That area is usually grouted instead of caulked; are you sure it's caulking?

Thanks Dave and Kurt, I'll get a picture posted today. The pool is currently covered and winterized, but this is a good reason to get the cover off early. Actually was planing on doing it this week anyway. I'm fairly certain that I could penetrate the caulking , or grout, with a finger nail last season, but I could be wrong. The joint being grouted just makes more sense. Look for a new posting and confirmation if it's caulking or grout today. Thanks again. Scott

Well that didn't take as long as I expected. Just removed some of the cover tension springs and pulled the pool cover back from a corner to get a peek for the camera. I believe it's caulking. The gap is about 1/4" at the minimum to 1/2" in some spots. It's not grout, like the tile grout, as I can stick a finger nail partially into it, it's chalky and has some flexibility to it. I've attached two pictures for reference. Let me know what you think. Thanks
Scott

I think you're right that it's caulking. I don't know enough about that to make a recommendation.

Hi, Scott,

(nice pics...thanks) (nice coping, too...I like that look)

Pretty sure that's acrylic caulk (acrylic shrinks). Too bad they used such nice coping material and short changed on the caulk.

Anyway, I believe your course of action is to remove the old caulk and replace it with a high quality polyurethane caulk. Removing the old is probably going to be 75% of the work. I'd start on a small section and get your system perfected start to finish.

Once you get the section cleaned out...doesn't have to be perfect...be sure to use masking tape on both top and bottom of the new caulk line. I have had very good success with a caulk named Vulkem 911. Comes in many colors and not too much money...about 3.25/tube, I think.

Again, the poly is tough to work with (not water soluable) and takes days to dry out but you'll never have to replace it again.:)

Dave S.

Thanks Dave. Spent 5 minutes searching the Web for Vulkem 911 and get several hits but have not found a site that sells it. Any idea where I can get this stuff? Also, replacing the caulking is just one of many items on my spring startup list for the pool. The list includes, pool caulking (which this is about), acid washing pool, replace pump seals and replace pool decking caulk (the stuff you walk on). Since I'm doing all this, I'm just wondering about your comment, 'nice coping, to bad they used caulking'. If I am going to remove the caulking and drain the pool, is there another choice that would be better? Hate to go through all this and find out later that I could have had xx but I settled for yy. You know what I mean? The extra work I'm not worried about and if the xx is only a few more dollars but better for the long run and aesthetics, why not do xx. Anyway, your thoughts and help are appreciated. Thanks Scott

Hi, Scott,

I misled you a little on that post. I should've said "too bad they used acrylic caulk instead of polyurethane caulk" You must have a flexible seal at that point because the pool vertical wall and the coping move independently of each other...not much, but they move. If you try to grout it, it will crack before you know it and possibly fall out if your temps are extreme enough.

I suspect they used acrylic caulk on your expansion joints on the decking as well. Again my advice would be to switch to poly when you get the old cleaned out. The depth of the caulk should roughly equal the width of the gap you're filling. Masking tape on each side of the joint is mandatory.

I got that Vulkem stuff at a local (I don't think they're a chain) industrial supply house that specializes in masonry accessories. Drains, waterproofing, etc. It's called "General Materials" The Vulkem is made by a company called Tremco. I'm sure there are others just as good but this one works so well for me, I've never attempted anything else. I hope you are able to locate it but, if not, talk with some concrete pros in your area and ask them what they use to seal expansion joints.:)

Dave S.

Thanks Dave.. Going to Reno on Friday and have some concrete supply stores to call on. Appreciate your help.

Kind Regards,
Scott

You might want to look at Vulkem #116 instead. The same colors as the #911are available, but #116 is suitable for continual immersion. I work for a company that sells Tremco products for the concrete industry, and we sell tons of the stuff to the pool builders in my area (Oklahoma City). If you go to Tremco's website you can find a dealer in your area. Out of all the different polyurethane sealants we sell, #116 is the only one I would use in your situation. It is probably around $0.50 per tube more, but worth it. Great product.... (by the way this is not a sales pitch)

Hi Dave, couldn't find Vulkem 911 in Reno on Friday but did find an equivalent. "Sikaflex 1a" Polyurethane sealant". Has all the same properties and performance as Vulkem 911. Now for the million dollar question. Is there a trade secret for removing the old polyurethane sealant? Over the weekend I have tried using a sharp utility knife, a high speed burr, chemical softening agents, other tools that will not be named and bad language, nothing penetrates this old stuff. I have searched the Internet and found solutions that involve heating and scraping the caulk, cutting the two edges with a special diamond blade ten pulling the caulk out, and more chemicals that are suppose to soften the old caulk. What am I missing? Thanks.

Kind Regards,
Scott

Hi, Scott,

I simply do not have a good answer. I've only installed it...never removed it. I can imagine it is a real pain trying to get it out of there.

Scott you might try johnbridge.com. It's a forum much like this one but for ceramic tile. Lots of really knowledgeable guys on there and they may have a good answer. If so, I hope you'll post back and let me know, too.:)

Hi Dave, well after I posted my question regarding how to remove the old caulking, I went out at lunch time to my local hardware store to take a look at their inventory of hand tools thinking maybe I would see something that would help with the removal. I left there with a 1/4" wood chisel. Got home and spent about 10 minutes with the chisel and was able to remove about 2 feet of the old caulking. Initially I had troubles getting the chisel started into the old caulk. I took a 'sharp' utility knife and made a verical cut into the caulking. This allowed me to get the chisel under and into the old caulking. Once I got into it, it was just a matter of applying a slight tug on the old caulking with one hand while wiorking the chisel into the edges and under the caulking with the other. The stuff just started peeling off, but it did take considerable work and force in some spots. Tonight after about 2 hours I removed half of the old caulking. Only another 55 feet to go.....I will have to go back over the exposed joint with a wire brush and compressed air to remove the loose material and pieces of caulk that still remain, but the 1/4" wood chisel does the trick. Here's a tip, about every 5 feet I would stop and sharpen the chisel. It looses it's sharpness rather quickly against the concrete and tends to push the caulking out rather than cutting and lifting. Mayber I will post a picture to document my progress. This is step one of many before the pool is open for the season. Thanks again.

Kind Regards,
Scott

Hi, Scott,

That's cool!! I don't think I would ever have thought of that but you can bet I'll file it away for future reference.

Sounds like you're being really thorough on your pool renovation. Gives a lot of satisfaction to do good work on a difficult task, doesn't it? :)

Dave