Metal Roof Leaks

[RickW]

We have a used 1987 Victorian Single Wide Mobile Home. The master bathroom ceiling has a new ceiling over the orignal. It was like that when we bought it. We had a water leak 2 years ago and recoated the roof with fiberglass cement. The guy at Lowe's recommended a rubber squeegie applicator which wasted so much coating it didn't spread out the coating enough so I know we surely put it on thick enough. Anyway we have a leak again. Not sure what to do. Can we just put the coating on the seams and around the pipes on the roof? We live in PA and it is still cold. Do we have to wait till spring to do this? The tiles in our bathroom are the 12" type that slide into each other so it hasn't been fun replacing them and repainting the ceiling. One other thing, we didn't put the cement around the rolled edges of the roof because we were afraid that it would run down the side of the mobile home plus they didn't look bad. Maybe this is where we screwed up. Would the roofing cement in a tube work for that since it is thicker?

[JD]

If you are sure the leak is coming from a bath fan or plumbing vent, it may be easier and more efficient to remove the vent and install one with a bigger footprint. The install is easy. Clean the area real well (I use lacquer thinner). Put a thick bead of polyurethane roofing sealant (I use Tremco Vulkem 116) around the bottom edge of the vent base and screw it down to the roof. Sealant should ooze out from under the vent edge. Incorporate that ooze with additional sealant to totally seal all edges and screws. Take care not to create air pockets while swirling the sealant around.

That part of the roof that folds over the edge and inch or two, being held down with some type of J-track or termination bar, is the most important part of your recoat. This is where most mobile home metal roof leaks come from. Having two ceiling layers may cause the leak to travel from it's origin, so it may not look exactly like an edge leak. As with any paint/sealant product being brushed on, prep is key. If the old sealant is stuck good and not cracking or peeling, a good cleaning can be sufficient for for a couple of years. Removing old sealants completely will usually give you better results. But be careful with this part as the original roof below all the old sealants could be badly rusted, making this easy repair not so easy.

I use commercial sealants that you usually won't find in home stores, but it is very much like Snow Roof, Kool Seal and Henry's Elastomeric (only a lot better). When recoating a roof surface, the edges and vents are usually hand brushed before rollers or squeegies come out. I usually use a cheap straw push broom and then paint rollers. I think it is best to apply a good base coat (after clean/prep of course), let it fully dry and then hand brush another coat. I will then do the roller work, multiple coats recommended for most products. Then I will usually brush on top coats on edges and vents.

[RickW]

I'm not sure where the leak is coming from but today I took a couple more ceiling tiles down and stuck my hand up there and felt wetness on the edge of the old ceiling. So I am going to have to put some roof coating around the most important part of the roof, the edge that curls over. The J-track you mentioned has to be the metal gutter-like piece that goes all around the home. What temp does it have to be to apply roof coating? Thanks for your advice.

[bobfather99]

I do know that Kool Seal recommends that outdoor temps be 50 degrees and lower humidity for best results, with 4 to 6 hours drying time. I would assume that a similar product would be the same.