Do you have a leaking fiberglass roof?

[sbranen]

I have a 2012 Tiffin Open Road Class A Motorhome. I experienced a leak around the vent an d I had La Mess RV in San Diego seal it. They used Dicor and it cracked and could easily be pealed off the roof with your bare hands. I call Tiffin Motorhome Company and they told me their fiberglass roof should be sealed with CSL 515, white silicone caulking. I had it sealed with CSL and it worked perfectly. If you need some you can purchase it by calling Walcott-Park Inc., 1-585-342-3120Ext. 100. This is the only place I could find CSL. I hope this helps. It costs about $6.50 a tube.

[Haleyjean50]

Is this for Tiffin Fiberglass Roofs Only? Or should it do well on any fiberglass roof?

[sbranen]

I wouldn't swear to it but why wouldn't it work just as well for all fiberglass roofs? It is a heavy duty commercial silicone product used and recommended by a major motorhome manufacturer, (Tiffin). I would call your your motorhome manufacturer and see what they recommend. Whatever caulking you decide to use, always completely clean off the old caulk and use an effective cleaning agent to prepare the area you intend to reseal.

[PyrateSilly]

Never will I ever put silicone on my RV roof again!! We decided to go with a product from Teakdecking which is rated for marine use so it flexes and works well around water. Some go with marine caulking from 3M.

[Gary RVRoamer]

I wouldn't use silicone cause it is problematic to ever coat anything over it again, including more silicone. There are other excellent products for use on fiberglass, e.g. Geocel Proflex RV, Surebond SB140, Geocel MHRV 2300, Sikaflex, 3M Body Seam Seal, etc.

Besides, failure of the Dicor to stick is more likely inadequate prep work than a problem with the fiberglass. There is, however, known incompatibility of Dicor with some types of plastic, e.,g the acrylic plastics used in skylights. That results in cracks in the plastic, not leaks.

[docj]

The caulk being recommended seems like it might be a bit different from the silicone caulks we all are used to buying at Home Depot. Here's a link to the website for it:

CSL 515 Self-Leveling Industrial Sealant - Overview | CSL Silicones Inc.

It looks as if finding a place to buy it might be a problem. I'm only speculating, but I wonder if it has any relationship to this sort of product which I have had good luck with. It is sold for boating applications:

Amazon.com: Boat Life Lifeseal Sealant Tube, Clear: Sports & Outdoors

This calk is a polyurethane/silicone mix of some sort.