I have a mid 70’s house with a tiled shower in the MBR. The pan appears to to plastic of some type. Previous owners placed silicon caulk over
the original heavy mastic-ie stuff. And maybe a prior layer of silicon,
as the caulk has peeled after just 3 years.
I’ve got the vast majority of the caulk off and have cleaned up the mold. I have DAP caulk remover that I’m going to use this afternoon to get the final traces of the caulk off with.
The tile-to-shower pan gap varies rom around 1/4″ to about 1/2″. Once I’ve got everything cleaned up should I re-caulk with bathroom-style
anti-mold caulk or use something else?
Replies
With gaps that size, you need to close them with a backer rod. You can usually find it at HD & Lowes in the same area as the window and door insulation. Or you could buy a package of foam window insualtion and use that.
Use a caulk for bathroom because it contains a mildewcide that helps prevent growth of old & mildew. Buy the best you can find.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Be sure the joint is COMPLETELY clean -- the new caulk will not adhere if there is ANY old caulk left, or any film or grime. Scrape surfaces with a razor scraper, wash with water and a few drops of detergent, then with rubbing alcohol (helps to dry and degrease). Let dry and then use a name brand "bathtub caulk" (mold-resistant non-paintable silicone caulk).
Use backer rod in any areas much wider than 1/4". Set it to a depth so that the caulk at the center of the joint (where the backer is fattest) won't be much thicker than 3/16" front to back. (Understand that a layer of caulk that's too thick front to back is less flexible than a thinner layer, and thus more likely to separate from the adjacent surfaces.)
"Tooling" the caulk (creating the desired profile) is an art, and one that varies with the circumstances and the specific caulk used. Sometimes it's best to not tool at all -- just use the tip of the caulk tube to shape the "bead" as you go. Other times a wet finger or one of the various caulk tools may help. Have plenty of paper towels handy.
This is a tedious job, the sort of thing that would cost a fortune if you paid someone to do, and then you wouldn't be sure they'd done a good job. Ideal DIY job, once you know the ins and outs.
Just got done re-caulking my own shower about an hour ago. I've always hated silicon because it is so hard to work with (old opinion). I dug out the old caulk (acrylic latex with silicon) which had only been in for three years. I did my research on this site yesterday for tooling techniques and went to town. Yesterday I bought silicon BATH caulk (DAP Titanium Silicon)and some denatured alcohol (not isopropyl). I removed all the old caulk with razor blades and a utility knife.
I'm a convert! I now love silicon. Before caulking clean areas to be caulked with alcohol. Then cut tip of caulk tip just slightly larger than with of area to be caulked (cut straight not angled), a good caulk gun is very important (cheapies won't cut it)use backer rods for wide gaps, hold the gun perpendicular to the surface being caulked, and apply at a slow even pace. Here is the biggest thing that helped me. I always hated silicon because it was hard to work. I read a post yesterday about dipping your finger in the alcohol to work the silicon. That is the best post I've ever read off this board. Keep your finger wet with alcohol to shape the silicon. With this technique the silicon is as easy to work as latex caulk with water and you have a far superior caulk job.
Good luck,
John
J.R. Lazaro Builders, Inc.
Indianapolis, In.
Here is an "update"... The DW had been bugging me to recaulk the shower since there was some mildew on it. I spent maybe an hour with a razor scraper cleaning off the old caulked. Recaulked with GE Silicone II. I used clear up against the metal shower door frame and white between the slabs of cultured marble. I first smoothed out with my finger and then I used the denatured alcohol on my finger to dress it out. Sure enough it made the silicone much easier to work with.
One problem. It's now been 30 hours since I did the job and some areas are not drying. The only thing I can think of is that I had a little too much alcohol on my finger some of the time. What now? Heat gun?
So - preliminary diagnosis is to be very careful not to use too much alcohol.
The caulks cure with moisture. If it's terribly dry in there run the shower a bit (taking care to not strike any soft caulk with the spray).
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Thanks for the idea. I poured some water on a section. I'll check tomorrow to see if it helped. I've probably used silicone caulk about 1000 times. This just isn't right...
I don't think the caulk cures with moisture. Adding water did not help. I don't think it is gonna impact things negitivly - also - I only put the water on about a 6" secion out of priobably 8' of caulk beadn
Edited 9/19/2006 6:19 am ET by Matt
I used quite a bit of alcohol. Mine took 24 hours to cure to the touch.John
J.R. Lazaro Builders, Inc.
Indianapolis, In.
John - wouldn't you say that normally silicone dries to the touch in about 4 to 6 hours max? Maybe everything is cool and I'm just being impatient? I wonder if denatured alcohol is pretty much the same solvent that is in the silicone?
re what Dan said about moisture curing it, the outside humidity was 90% this morning and is 80% right now. I have no idea of what the RH is inside, but I have no reason to believe it is much drier inside than outside.
I've been doing a bunch of caulking for clients and the best tip I ever learned was not paper towels but instead use the plastic grocery store or home depot bags for wiping your finger.They are plentiful, cheap and silicone wipes off your fingers with them easily.You may go through 10-15 of them on a tub - but it's worth it.JT
I'm no expert but I do know that the alcohol slowed the curing process. My opinion is that high humidity slows the curing process. I would not present any moisture until the silicone has at least cured to the touch. My shower was still very tacky in 12 hours but cured to the touch in approx. 24. I would give it a little more time.John
J.R. Lazaro Builders, Inc.
Indianapolis, In.
Thanks for the update: you think the denatured alcohol slowed the process. I think I may have 2 things going on here. See next post.
Matt,Silicone RTV caulk does not have a solvent in it per se. Also, it releases water as it cures. Urethane is the caulk that adsorbs water as it cures.Old silicone sometimes cures very slowly or never. The high humidity may be retarding the cure on your job. Silicone "2" (oxime cure) becomes icky grease when it gets too old. Check the date on your tube(s). Silicone "1" (acetic acid cure) tends to just harden when it is too old.Hope this helps.Bill
>> Old silicone sometimes cures very slowly or never. The high humidity may be retarding the cure on your job. Silicone "2" (oxime cure) becomes icky grease when it gets too old. Check the date on your tube(s). Silicone "1" (acetic acid cure) tends to just harden when it is too old. <<
Very interesting to hear the difference between the 2 types of silicone. I hadn't really thought about it much but now that I do, I think I read some years ago that there was a new silicone that had much less VOCs. This Silicone II definitely doesn't have the strong odor of the regular less expensive stuff, Silicone I.
The date on the tube: "USE BY 3/07". I bought it about 3 months ago at Lowes. At that time, I had roughly 40 tubs to caulk in an apartment complex - new construction - I wanted to do a good job so I went and bought maybe 6 tubes of what I hoped was the "good stuff". If I remember correctly is is > $5 a tube. I also didn't want mold/mildew to be a problem in the near future and had mixed feelings about using silicone caulk at all. I only had to caulk the front of the tubs where it interfaced with the VCT flooring and didn't have a better solution. The other seams had been caulked/painted by the painters.
This tube I used 2 days ago was left over from that job. It was unopened. Here is the thing though: it was in my truck for roughly 2 months before I brought it inside to the AC. So the caulk went through a bunch of heat and cool cycles with the hot Carolina days and the sometimes cool nights. Now that I got out a magnifying glass and read the instructions on the tube it says "store in a dry area at less than 80 degrees F".
So, what I suspect at this point is that the caulk was messed up from the heat/cool cycles, and to a lesser degree the alcohol might be slowing down the cure process too. I don't think the humidity is having much effect on it. Like I said, I've probably caulked with silicone about 1000 times - never had a problem before - although now I'm wondering if experiences with Silicone I type caulks has anything to do with using the somewhat less common Silicone II.
The clear Silicone II I used on this job I bought from the store 2 days ago. It seemed a little slow to cure, but was 'done' within 24 hours.
I set just up a little home experiment. I put 4 beads of silicone caulk on a non-porous surface: 2 beads of the white Silicone II I'm having trouble with, and 2 of the clear Silicone II that is "new" and worked OK. I "tooled" each bead, one of each color with just a bare finger. One of each with denatured alcohol on my finger. Tonight I will check to see how the curing process is going.
I wonder if Silicone II is less compatible with the denatured alcohol than Silicone I. Obviously they are very different animals. I do know that the Silicone I stuff I have left in my truck with no problems other it getting hard when old.
Doesn't it just suck when you try to do a really good job at something and it looks really nice and than all turns to sheet! Right now all I have is a sticky mess.
OK - here is the summary:
GE Silicone II goes bad fairly quickly when stored in a hot location.
The Denatured Alcohol doesn't effect the curing process appreciably.
Now I get to scrape and clean out the sticky mess and start over. Great!
Bill: do you know - specifically any other brand/type of caulk that won't dry when it gets old? Every other caulk I can think of just gets hard when old.
Matt,As far as I know from personal experience, only Silicone 2 turns into greasy slime that will not cure. Like you have seen, all the others just get hard.Denatured alcohol is your friend as you clean up the mess. Be sure to wear gloves, as the methanol component is very toxic and crosses through skin like it isn't there.That part about storage conditions is very interesting, and new to me. No more Silicone 2 living all the time in my truck!Bill
Thanks Bill
Sometimes it just makes it better to have someone to commiserate too. At this point the DW thinks I'm a DA :-) No commiserating there... BTW - we do have a second full bath.... :-)
Please, please,,,,,,,,,what does DW stand for?????
I think I know, but need confirmation. Thanks.
http://grungefm.com
dish washer
dry wall
dear wife
damn woman...
doo whop..
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
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Forget the primal scream, just ROAR!!!
Thank you.
I had at least one of them!! (Dish Washer - wife)
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I used a mildew resistant sanded caulk on my shower surround. Caulk matched the grout nicely, but does not resist the mildew.
I was considering grinding it out. Caulking it again with the colored caulk, then putting a layer of clear silicone caulk over the colored.
Anyone have a suggestion for clear silicone caulk that will eliminate the mildew issue?
I've used GE II before, but never in a bathroom.
Silicone won't stick to silicone.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
The colored caulk is laytex. Looks nice, but doesnt hold up against the mildew.
I was hoping the silicone would.
Colored silicone caulks are available, though not in as wide a variety of colors.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
JohnYou can use rubbing alchol also for tooling the silicon.In fact it you don't like the results or get a smear, etc, then you just wipe it off with the rubbing alchol.
If you are fussy about the look of the finished product, I have found a little blue painters tape works well for me to get the nice clean edges I am looking for. I tape off either side of teh joint where I would like the bead to be at it's widest, when apply a nice bead of caulk and smooth it out with a wet finger and plenty of paper towels, as keeping the finger clean is critical. I smooth out the caulk untill the edge of the painter's tape is just barely visible through the caulk, then I slowely peel away the tape making sure to pull the tape away from the joint, so you don't drag it through the newly applied caulk. after that you should let it cure for 24 hours minimum.
I have been using GE Silicone II (link) for quite a while with great results. I have done some research on it, an reviews are positive.