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I have a 10 yr old tar & gravel flat roof with a dozen penetrations for solar panels, vents, solar plumbing, exhausts, chimneys, etc. As preventative maintenance every year, I scrape off gravel in deteriorated areas and re-flood with hot tar and re-embed the gravel. It’s a hassle and never 100% effective.
What alternatives exist to tar and gravel for flat roofs and where could I find information and material sources that a competent DIY could use.
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do not know wher you live but what I tell the people with flat roofs here in oregon that the only fix is trusses making a real roof. Other then that then look into the poly roofs. The one we used was 30 mils thick, went over two layers of felt and hasnt leaked yet, but even still, out here I did not want to do it and have fears of it failing. not because of workmanship but because it is a flat roof, and to me flat roof s in Oreogon work by magic kinda of like shake roofs on skip sheeting........magic
*b TVMDCChris, The only alternative to tar and rock I recommend is Modified Bitumen but this is definately NOT a DIY application.First, the best approach would be to tear-off the existing roof membrane, inspect and repair any sheathing, install new flashings on the roof penetrations and edge metal, then apply the glass base sheet and burn-down your MB. Modified typically comes with a 12 year labor and material warranty if applied in this fashion. Longer warranties can also be purchased.If you are not going to tear-off the existing roof, you will first have to spud it (remove the rock). At this point I install 90lb cap sheet seconds upside down to protect the subsequent layers from the residual rock. Then glass base and the MB. Typical warranty for this application would be 5-10 years.However, MB has a potential useful life of 25 years providing you have good drainage and do routine maintenance to the roof penetrations.You may want to look here for a lengthy discussion on flat roofs: click the "ALL MSGS" box to see the entire discourse.You can look here too for another discussion on flat roofs with a liquid coating solution.Good luck!
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Bill,
Many thanks for your thoughts and links.
Chris
*Josh,Thanks for your thoughts on the flat roof/tar and gravel problem. Trusses not realistic, but I'd like to learn more about poly roofs. Any information sources you could point me to?Chris
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If you can find a Trocal installer, I believe it has a 50 year warranty. It is a one piece rubberized roofing. About $8 to $10 per square foot, I think.
*b TVMDC$8 to $10 psf equates to $800-$1000 per square (100sf). Tear-off and MB should come in around $300-$350/square. If you get 25yrs on a MB membrane, doing it again in 25 years (assuming no tear-off then) would run only $600-$700/square. And with the money saved, you have DSL instead of a dial-up connection.
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I have a 10 yr old tar & gravel flat roof with a dozen penetrations for solar panels, vents, solar plumbing, exhausts, chimneys, etc. As preventative maintenance every year, I scrape off gravel in deteriorated areas and re-flood with hot tar and re-embed the gravel. It's a hassle and never 100% effective.
What alternatives exist to tar and gravel for flat roofs and where could I find information and material sources that a competent DIY could use.