Opinions requested for Elastomeric Roofing Products

Old 04-04-10, 10:05 PM
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Opinions requested for Elastomeric Roofing Products

I've got a 10 year old roof of cast concrete tiles instead of clay tiles. I'm on the ocean, in the Bahamas, right in the hurricane zone. The roof was construction is as follows: 3/4 exterior plywood, then 1 layer of roll roofing, then the concrete tiles were applied with galvanized nails. Ridges were capped with concrete and clay half round tiles.

Now 10 years later, the galvanized nails are failing, and two spots have had tiles slide off during hurricanes. There is leaking in a variety of spots, as about 1 in 100 tiles are cracked, water in through the cracks, gets onto the roll roofing and comes down the corroded nail punctures through the 3/4 ply, and down my ceiling.

One thought i had was to remove all the tiles, remove the roll roofing, put down ice and water shield, then reattach the concrete tiles using stainless steel screws with stainless washers, and using construction adhesive to glue each course down where the drip edge meets the surface of the tile course beneath it.

But I think that would be a HUGE job (someone said several months for 3 people) as the roof is about 5000 sq ft.

Someone else suggested applying an elastomeric primer, then a bonding sheet to bridge the gaps between tiles (up to 3/8 inch), and then two coats of elastomeric top coat. I thought if it was put down with an airless sprayer, the work would go much more quickly than the reattachment option described above, and the membrane would make one continuous sheet that would greatly reduce any further nail failures, and even with failures the sheeting and membrane might glue/hold the whole thing together even during a hurricane, especially as wind would not be able to get underneath it (the first course of tiles is secured to the roof at the drip edge with concrete).

I also saw a product which was supposed to be a liquid EPDM, and thought that might be a better product. As the water off the roof is used in cisterns and then to bathe with, I'd like to keep toxicity to a minimum, and hopefully charcoal filtration can remove any inorganic toxins that might leach off whatever coating is used.

I am looking for recommendations as to the best course of action to take, and the best product to use (elastomeric, acrylic, EPDM) etc if the coating product is the way to go (and I would also get the benefit of a cooler roof since I would use the white reflective coating).

Old 04-05-10, 05:44 AM
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Welcome to the forums!

I'm not a roofer so I don't know a lot about the different ways to do your roof but I used to be an employee of an outfit that specialized in an elastromeric roof coating system. I wasn't too involved in that portion of the company but when the boss bought an old house [zoned commercial] we built a warehouse type room with a flat roof connected to the house.

I don't remember the brand or exact names of the products we used but basically we coated the plywood, applied a membrane and then applied 2 coats of an elastromeric coating. I was very skeptical but I worked there another 10 yrs and the roof never leaked
Old 04-06-10, 07:58 PM
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The elastomeric that I use recommends cleaning the surface with TSP first the applying two coats brushed on and perpendicular to each other. Not sure if it can be sprayed on. Not recommended for over roofing like shingles. Can use on cement or unglazed tiles. Not recommended for areas with standing water (flat roofs) unless using their primer. Does reduce roof temps reflects 90% of suns rays.
Old 05-06-10, 05:49 PM
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Best option:
Remove tiles and paper to deck.
Install full modbit 20yr system.
Reinstall tiles properly with stainless fasteners only.

Next best but not so pretty:
Spray polyurethane foam over everything with a coating which can be colored.
Hurricane proof, waterproof.
Must be professionally done with a spray rig.

Any other elastic coating wont last very long in my opinion.

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