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Old 06-21-2009, 10:42 PM  
miamicanes
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Well, I talked to the homeowner association's site manager on Saturday, and his opinion of elastomeric roof coatings was pretty high. He said that you basically need to re-coat them after every hurricane and every few years, but as long as you do that, they'll last indefinitely. The downside is that if you intend to PAY someone to do it for you, it's really expensive. The upside is that if you don't mind spending a few hours on the roof, it's easily DIY-able. Normal asphalt-based roofing is minimally (or not at all) DIY-able.

I was actually surprised by his opinion of sprayed polyurethane foam. His opinion was that it's one of the best systems if you can afford to maintain it... but said they're expensive to maintain (they need more foam added after every hurricane), and unlike elastomeric roof coatings, you can't do it yourself. He said if we get lucky and have 5-10 years without a direct hit by a major hurricane, the added insulation will easily pay for itself... but if we have another year like 2004, the roof repair costs will eat up the previous decade's worth of savings.

It's important to keep in mind that my roof differs in at least one significant way from most residential flat roofs: it's concrete. That means there's zero risk of hidden damage to the roof deck itself -- there won't ever be rotten boards, moldy plywood, or termite-weakened rafters/trusses. The roof cladding is important, but its ONLY role is waterproofing what lies below. It has zero structural value or importance. As long as it keeps water away from the roof deck and penetrations, it's done all it needs to do.

Plus, as I pointed out to my mom this afternoon, the danger of falling is minimal, because it's basically a flat slab. My only real danger is if I try to carry a 5-gallon bucket up a ladder, instead of renting a scissor lift. I might risk carrying things like a 1-gallon pail of roof cement up a ladder, but if I'm doing a full tear-off of the top layer, there will most certainly be a scissor lift present to transport the new materials up, and the old roof materials down.



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Old 06-22-2009, 04:56 PM  
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I have no knowledge of polyurethane foam vis-a-vis flat roofing.

My experience with elastomeric coatings is that I heard of them and learned about them through people I know who are knowledgeable about paint. Elastomeric coatings are used on exterior walls of masonary structures to bridge any active gaps. Basically, the coating is made of the same plastic as that toy "Stretch Armstrong" so that it will stretch to cover a widening crack or gap, but will revert back to it's original shape once the gap closes back up again. I really don't know what the difference is between an elastomeric roof coating and an elastomeric coating for the exterior of a masonary building, but I'm confident that a paint-on coating won't be as durable as a built-up roof membrane like your roof originally had on it. If your homeowner's association has experience with the rooftop version of an elastomeric coating, and is impressed with it, then he has more experience with that material than I, and I would trust his assessment more than mine.

It's true that your concrete roof deck will not be affected by a leaking roof membrane. However, that concrete roof and the interior walls of your house have plaster or drywall on them, and those will be affected by water.

If you're house is only two stories, you can get by without a scizzor lift. You can use a ladder to carry 1 gallon pails of plastic cement up the ladder, but you have to have a safe and secure ladder. A SAFE and SECURE ladder is one which:

A) is tall enough that the top of the ladder is a good 5 feet or so above the elevation of the flat roof, and

B) is secured to the steel flashing (or anything else that's sturdy) on the roof edge with a bungee cord (or any other strong cord) to securely hold the top of the ladder and prevent it from moving. If your ladder has hollow rungs, then consider running a bungee cord through one of those rungs and clipping both ends on your roof's steel flashing. If the exterior of your building is brick, drill some holes in a mortar joint, insert some plastic or lead anchors, screw some eye-hooks into those anchors and hook your bungee cord onto those eye-hooks. When the roof is done, drill out the plastic or lead anchors and refill the holes with new brick mortar for an invisible repair.

You want to make sure that your ladder is high enough to COMFORTABLY step onto the roof from the ladder and vice versa. You also want to secure the top end of the ladder to something sturdy so that the ladder doesn't move. You need to do BOTH of those things to have a safe ladder.

You climb up the ladder until your entire body is above the elevation of the roof, and then step off the rung of the ladder onto the roof with whatever foot you normally step forward with, swing your body around so that your center of gravity is over the roof, and then step off the ladder onto the roof with the other foot. Similarily, when you want to come down from the roof, you step from the roof onto a rung of the ladder that's close to the same elevation as the roof, swing your body around so that it's in front of the ladder and then step onto the ladder with the other foot. That is the SAFE way to get onto and off of a roof with a ladder.

(Whenever I see newbie DIY'ers with their extension ladder just a foot or two above a roof line, I just cringe knowing what a balancing act they're going to have to do to get back onto that ladder for the trip down, and it's especially scary since I know they probably didn't secure the top of the ladder to prevent it from moving. Often, these newbies have extension ladders that will reach higher, but they simply don't know how to set up their ladder properly. It's foolish and dangerous at the same time.)

If you set up a safe ladder, you shouldn't have any trouble carrying up a gallon of elastomeric roof coating every time you go up to the roof. You can buy empty 1 gallon paint cans at many paint stores. If you can only buy the roofing materials in 5 gallon pails, separate them into 1 gallon quantities at ground level, and carry them up in smaller quantities.

Any place that sells roofing supplies will typically have a truck with a conveyor belt to deliver the materials you need to the roof.



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Old 06-22-2009, 07:49 PM  
miamicanes
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Well, some bad news and awesome news.

The bad news: I talked to someone at the building department. He's heard of Ames Super Elasto-Barrier, and thinks it's a wonderful product. Unfortunately, Ames never bothered to get "Dade County" approval for it, so it can't be used to satisfy code requirements. Put another way, if I have a roof that's code-compliant, I can paint SEB onto it with the building department's enthusiastic blessing. However, if I rip off the Cap Sheet (I finally learned the proper term for "the sheet that forms the top layer of a South Florida built-up roof), I have to replace it with a new one, using materials that have official Notices of Acceptance by either Dade County or the State of Florida (HVHZ). So, there goes the idea of tearing off the Cap sheet and replacing it with Ames' products.

The awesome news: independently of the whole drama unfolding at City Hall, my parents decided that they didn't want me to risk heatstroke, falling, or future roof leaks (I'll argue about the last two, but won't really dispute the first... it was so brutally hot & humid on Saturday, just *being* on the roof was (literally) dizzying). So... I have 3 more roofers coming out tomorrow to give estimates... one of whom explicitly does ONLY repairs (and clarified that the scope of "repairs" includes "tear off the cap sheet, replace it , and replace/repair/improve any damaged/deficient flashing), just to ensure that I have at least one roofer coming who won't try to talk me into a complete tear-off and replacement just to make more money.

It's just a hunch, but I'm getting the definite impression that the likelihood that a given roofer is willing to repair the existing roof by tearing off and replacing the cap sheet is inversely proportional to the company's size... big corporate-type roofers have paranoid lawyers who won't allow them to do anything that's not 100% under their control, the smallest roofers don't have the equipment to DO a complete tear-off and replacement, and the happy medium lies somewhere in between... the ones big enough to be able to get the equipment they need to do the job, but small enough to be willing to let common sense rule and do a partial replacement at a competitive price if they think the lower layers of the current roof are good enough to last another 10-20 years.

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Old 06-22-2009, 09:14 PM  
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It seems reasonable to me that if this "cap sheet" is the top layer of a built up roof, then it's the one that's going to deteriorate the most as a result of exposure to the Sun and the local weather.

I'd point out the areas under the blisters where you found the underlying roof membrane to be in good condition to the roofing contractors and see what they think about just replacing that cap sheet.

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Old 06-23-2009, 12:27 PM  
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The top layer looks like what they call around here a "torch down" this is avalible with small granules impregnated in the surface. its not the same at all to the rolled roofing you can buy at the home center. Its good stuff - it just looks like it was sloppily applied and now leaking.

If you tear it off it will most likely take off the top layer of your built up roof if it was installed correctly (bonded with the substrate).

As for a repair? I'm not sure - when researching roofers look for someone who advertised "modified bitumen" or "torch down" or flat roofs.

Torch downs are going out of favor by some due to a high chance of fire if done unsafely. I think insurance premiums are going up for contractors who do them. Make sure your contractor is insured and trained.

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Old 06-23-2009, 04:09 PM  
miamicanes
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My roof has more drama going on than Broadway. Out of the 3 roofers who were supposed to come give estimates today, only one showed up (I can't entirely blame the other two, though... we've had torrential downpours & thunderstorms all day, with a tornado watch from ~10am until mid-afternoon). The one who came said it's definitely not torched, looks more like it's 15-20 years old, and looks like it MIGHT have been a post-Andrew hack job by someone who either didn't know what he was doing, or knew what he was doing and just plain didn't *care* because he had another roof to do the same day (Andrew's aftermath was kind of like the Wild West + modern Chinese manufacturing rolled in one; the only thing missing was the Russian mafia, and if Andrew had been in 1994, I'm sure THEY would have gotten a piece of the action too).

Getting back to the drama. They said they can't tear off and replace just the cap sheet for building code reasons. Apparently, they can slice open most of the roof's top layer to air out the blisters, then lay down another new layer on top of it with hot-mopped tar and qualify it as a "repair", but if they go all the way and REMOVE that top layer, they'll be required to tear off and completely rebuild the entire roof regardless of the lower layers' condition because the codes were changed again in 2007, and tearing off the cap sheet would trigger the full force of the new law with no gradfathering provisions. Well, either that, or they could tear off and replace the cap sheet for 1/3 of the roof per year...

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Old 06-24-2009, 05:31 AM  
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ok - so the obvious conclusion we are coming to here is the best solution is a rip out and replace. When you do that you have the advantage of being able to upgrade the insulation.

The thing that sucks is the cost. You said about $8K. That seems high but thats just a gut reaction. It may be right on the money.

So - What to do? If you know where the leak is just slop some of that roof cement on it and hope for the best. There are alos mop on coatings you can go over everything.

For a temporary repair I wouldn't worry about the "blisters". I would focus on the seams and the roof penetrations.

Then start saving. Keep an eye out for Obama money for energy efficiency upgrades. If you can get some of that we all are helping pay your roof costs! Yay.

Good luck

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Old 06-26-2009, 05:49 AM  
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Actually, the one quote I've gotten so far for whole-roof replacement is $9,100. Ouch. Not to mention almost a thousand dollars more than my neighbors paid to replace THEIR roof in the aftermath of Hurricane Wilma, when roofers could charge just about anything the insurance companies would bear, 2/3 of the roofs in Broward County needed to be replaced "immediately", and we were still at the tail end of a major construction boom.

The best repair quote I've gotten so far was $3,200 to slice open the blisters, then hot tar the whole roof, put down another cap sheet on top, more tar, and fix the flashings.

One question... are exhaust vent covers flashed to the cap sheet, or are they flashed to the roof deck or one of the lower layers of the roof? I'm thinking about replacing the two I have right now with these, but need to figure out what size to buy. If the existing ones are flashed to a lower level of the roof, I'll probably just cut off their tops, and put a sufficiently-large Aura-D vent over them & flash it to the new top layer (leaving the original in place, and basically adding the Aura-D on top for extra protection. On the other hand, if they're flashed to the existing cap sheet, I'll just replace them outright.

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Old 07-20-2009, 02:58 PM  
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Default Flat Roof Repair

As a junior member I recently learned I may not offer links to product sites, etc., until I've posted 5 times. This my second. Accordingly I'll only offer my generic thoughts and limited application-specific product solutions.

I reside in upstate New york where we've lived in a house attached to a flat-roofed garage, hot asphalt-mopped , for over 30 years. It's been one continuous headache. While you have your hurricane headaches, I have snow load headaches. During these 30 years , same as you, I've, slit, cemented. etc plus twice had the asphalt removed and re-layered anew, only to face problems, almost immediately.

Basically flat roofs are a disaster, UNLESS, and I'll elaborate as follows.

Unless you have 1/8" min. or 1/4" preferred taper per foot built in slope to prevent standing water. Standing puddles of water is the culprit. It seeps into the felt, the decking, the underlying supporting joists. Over time the static and live roof-load (asphalt's heavy, so is the deck, even more so the snow) imposes continual stresses on time/water-weakened joists so they deflect more and more, deeper puddles form, felt/asphalt cracks some more, etc.

The only way to have a successful flat roof is to slope it, slightly. This can be achieved with most of your present asphalt intact, or preferably removed to the deck. The latter allows you to inspect the decking and repair where necessary and helps subsequently achieve a smoother looking, lasting roof surface. The fly in the latter ointment is the hard work in removing, plus in the expense involved in proper disposal. Disposal here, in upstate rural NY, was quoted by roofing contractors, $2k-$3.5K last year, stripping labor not-included.

My 22'x36' flat roof DIY option resulted in researching a roofer's means for applying a tapered re-roofing solution, to a flat roof such as mine. The best solution appeared to be purchasing 4'x4' tapered closed-cell-foam insulation system from Bradco and attaching on top of your partially smoothed over asphalt or directly to the bared deck. Water proof the resulting tapered foam structure with cemented UV resistant rolled membrane, etc. and rest confident no puddling will reoccur. You can also over-coat with an appropriate white liquid coating to reflect heat. The closed cell foam insulation, in your case, also helps insulate the space under the roof deck. ECO friendly.

In my case I didn't go through with this approach. Admittedly was tempted by it's relatively, DIY low cost ( materials $2-$3k). But two factors ruled against it.

1. We always hated the look of the flat roof garage as attached to our gabled colonial cape.

2. The house is actually 60 years old (we're the second owners) and the originally installed joists have weakened over time and snowloads. Accordingly, I decided to bite the bullet and remedy the basic problem. Namely, "Get rid of the flat roof".

I won't elaborateon my project, since this is not an option for you. But briefly, I'm building a gabled roof over the flat roof. The trusses, bought from a local truss manufacturer, plus roof decking and shingles were paid for by the asphalt on my flat roof THAT WASN'T stripped and carted away for disposal. Now with no more rain or snow on the flat roof ceiling of my soon to be altered garage I expect those joists to have a long life.

Talk to your local roofing contractors about installing a "tapered" roof repair system. I feel it's DIY doable, since the foam panels are light and promise to be easy/fast to install (cover with a tarpaulin during rain showers prior to cementing the membrane).

For what it was worth. Hope I was of some help. Good luck.

This posting was my way of unloading my 30 years of flat roof misery brought to mind by your photos. Incidentally, we never used the flat roof for its original owner's intended purpose - namely sit and relax, reading the morning paper.



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