Fiberglass Roof sealant

[nazoomer]

Will "Through the Roof" sealant work ok on a leaking skylight?

[Martind4]

I haven't heard of "Through the Roof Sealant" so I can't advise you on it's use.

My tried and true method of repairing leaks is to remove the skylight, inspect it for cracks, and thoroughly clean the roof surface and the skylight of old caulk with methyl alcohol or acetone, whichever works better as a solvent.

Use putty tape or butyl tape on the skylight remove the paper backing and reinstall the skylight in the proper position.

I use one size larger diameter screws (#10 instead of #8) to insure a good bite into the fiberglass, longer screws really don't make any difference. If I can't use the one size larger screws, I'll mix some fiberglas resin/catalyst or bondo to fill the existing holes, let it cure and then pilot drill the holes with the right size drill.

Hand tighten the screws, power drivers are nice but it's very easy to overtighten and strip out the hole you just repaired.

Use Dicor self leveling sealant to seal the edges and screw heads.

I know this is more than you asked for, but I know for certain that this method works. Taking shortcuts on water leaks only means you get to do it over again sometime in the (near) future.

[Gary RVRoamer]

Here is the info on "Through the Roof"

Through the Roof!® - Clear Roof Sealant

The ad suggests it is ok for skylights and most plastics except for polystyrene.

On my coach Fleetwood recommends a special sealant for the plastic skylight over the shower. Regular roof sealants apparently can weaken the type of plastic used in the skylight. The recommended sealant is Surebond SB-140 Architectural Elastomeric Rubber Sealant

[Midniteoyl]

Butyl roof tape (eternabond type) works...

That 'Through the Roof' looks to be the same as Ultima. It works, but the heat of the roof during summer seems to make it 'sag', and the .pdf says 'Do not use on acrylic skylight glazing surfaces' so extra care is needed...