Bathtub Caulking

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Posted by: from Burford
12/2/2013 at 6:22:59 AM

Why is my new bathtub (in a new bathroom) constantly having the caulking peel off and a mildew shows quite fast on that part?

It has been recaulked once and it peels off in 2 areas. The bathroom was gutted and rebuilt last fall due to immense mold and mildew and caving in walls etc. Now its lovely. it cost us 11G with various friends making mistakes along the way.

Is this maybe yet another mistake?

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Juan Pedro from Bilbao Renovations in Montreal
Date/Time12/2/2013 at 10:19:42 AM

There may be a few reasons for your problem.

1 - Has the source of the mildew been corrected?

2 - Was the caulking that was applied 100% silicone or was it water based ?

3 - When the caulking was applied, was it done while the bathtub still had a few areas that were wet or humid ?

4 - Did you give the caulking enough time to cure before using the bathtub or shower ? Normally it takes about 24 hours before it cures completely, and that's when you are able to use the bathtub or shower.

I hope this helps.

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Date/Time12/2/2013 at 10:30:56 AM

I certainly agree with the other poster. You need to determine where the moisture is coming from. Also, try re-caulking one more time. Completely remove all existing caulking from the tub/wall and ensure that there is no residue, etc. from the existing caulking. Then, fill the tub with water and ensure all seams are thoroughly dry (I use a hair dryer) before re-caulking with silicone. Leave everything alone for 24 hours then let the water out (just because the tube may say "shower ready in 3 hours" does not mean you can take a shower then!).

Also, what mistakes did the friends make? This may also be a source of your problem.


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Date/Time12/2/2013 at 10:36:21 AM

There's various reasons for the caulking to crack and peel. Was it clean and dry when installed, is the tub moving when it's filled with water. The mildew is most likely because they used a water based caulk without a mildiscide in it.

Clean out and scrape all the old caulking and make sure it is completely dry. Use a silicone based caulk for bathrooms. There should be a small gap between the tiles and the tub, make sure that is filled also. If the tub is moving try filling it halfway with water and then caulk it and let it dry. If that doesn't work then you'll probably have to tear out some walls to fix it.

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Date/Time12/2/2013 at 10:39:37 AM


The other answers probably do the trick. When caulking or other sealants/coverings don't hold, it is usually due to the product not being able to adhere properly to the intended surface, thus peeling.The culprit may very well be the underflying surface. If it wasn't new material or if there was a leak, causing the dampness, there is your issue. The area behind tthe shower walls must be dry and clean for the sealants to do their job.

Sorry to say, but it may mean re-doing part of your wall.

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