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Aluminim Roof Coatings ?'s


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My name is Mike, first time posting here, not an inspector.

I have read through several roofing post and answers and I am very impressed with knowledgeable members here. I have a few questions I hope to get answers to.

My home is in the Tampa Bay area of Florida. The roof is 9 years old low slope that was initially installed using mechanically fastened single ply base sheet with hot-mopped adhered granulated SBS mod-bit cap sheet. The roof has minor water curling issues in the corners (2 foot extended eves), but no leaks within the home. The roof looks to be in good shape other than alligatoring at the peak and a few other small areas, and a few areas where the cap sheet is lifting up from the drip edge. Also there is an area of ponding that is less than a 1/2" deep.

Reading through some of the post here concerning flat roofs there is mention that alligatoring isn't necessarily an issue as long as there are no flaps and it isn't through the base ply. Also mention that water less than a 1/2" deep isn't much of a concern as well. However, the local ABC roofing supply company has advised me that alligatoring is a sign of the roofs near end and suggested that I can three course it with mesh and cement topped with granules to hopefully get more life out of it.

The also said don't bother coating it as is has the embedded granules and those help reflect heat.

I have been searching through many sites and posts to try and make a sound decision. I don't want to sink money into coatings that may not extend the life of the roof. Yet, a lot of people on forums have suggested using a good asphalt/rubber aluminum coating (such as Karnak) to prolong roof life. Another more expensive option is Hydro-stop or Soy Expandothane. Unfortunately, there are few reviews on those products. All feedback and suggestions much appreciated.

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My first take is the roofing company is attempting to trade on mythology. Alligatoring rarely means anything bad; it means someone slopped on too much tar.

9 years is barely a 1/3 of the way through the "normal" life of a mod bit roof in Chicago. Florida sun will cook stuff quickly, but 9 years should still have some life in it.

Put up some pictures if possible.

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Sorry for the delay. Pics attached. Recent eves repair was done using Polyglass polyfex peel and stick modbit cap sheet over(asphalt) primed existing roof with old roof cut back 18 inches from edge.

In the process of applying peel and seal to seams on insulated aluminum patio roof. I will also apply 12" peel and seal where the flat roof adjoins the aluminum patio roof. Plan to attach it to flat deck's drip edge facing and cover seams and old peel and seal on aluminum patio roof to form an L-shape avoiding any gaps.

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I'd put that in the basic half-assed install with the usual inadequacies. It'll work OK for some number of years.

I can imagine reflective coatings helping a lot; they work. Yes, I know the naysayers, give them some props, but my experience tells me UV inhibiting coatings work, and common sense says silver reflective coatings have to be better than black.

Reflective coatings would work here in all the little cracks and crazes you can't even see; UV still gets in there and breaks down the material. Yes, the granules reflect most of it, but in terms of area, there's probably some good percentage of area still exposed that doesn't have granule.

It's peeling in the corners because of the flashing material. Forget aluminum gravel stops/drip edges/flashing details. Mod bit doesn't weld to aluminum worth a darn. (I'll modify that to, it'll weld sorta ok if you double prime it and go overtime on getting the welds tight, but I'd still be watching it every year.)

You want minimum .032 galvanized; if you don't want shiny metal, use Keynar coated material (available in the usual brown, bronze, white colors). Double prime this stuff, and it'll hold forever. Well, almost forever.

What about venting? What's the roof structure? Is there an "attic" in there? All that magic membrane that keeps the water out also keeps the water in; I have a hard time imagining a single turban vent does much, but I could be wrong.

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"I'd put that in the basic half-assed install with the usual inadequacies. It'll work OK for some number of years."

I hope it holds up, so far the seams are good just a few areas of the drip edge are an issue.i agree with your assesment of a half-assed job. When it comes time for a new roof I want to add a pitched slope over the flat deck.Possibly go with metal througout or in combination. Please share your recommendation for type of (new) roofing.

"I can imagine reflective coatings helping a lot; they work. Yes, I know the naysayers, give them some props, but my experience tells me UV inhibiting coatings work, and common sense says silver reflective coatings have to be better than black.Reflective coatings would work here in all the little cracks and crazes you can't even see; UV still gets in there and breaks down the material. Yes, the granules reflect most of it, but in terms of area, there's probably some good percentage of area still exposed that doesn't have granule."

I have posted on other sites and read others that posted similar questions concerning roof coatings. Mixed responses for and against and for me it is value added (extended roof life and asthetics) versus initial and possible future cost of coating. Roofers and reps I have spoken with said that a good asphalt based fibered aluminum coating should last 3 to 5 years in Florida.Ponding area will need to be done annually.

I called Karnak and Henry and they both recommended doing a rubberized asphalt based fibered aluminum coating. The interior of my home is approximatley 2800 sq. ft. with garage included and has 2 foot eves (extended from main frame) around the perimeter. A rough guess in roofing squares is 30.The coatings coverage is 2 gallons per 1 roof square (100 sq. ft) which would equal approximately 12 to 13 five gallon cans, but will probably closer to 15 gallons due to granules. Karnak #298 is $98 (not including tax) and will total to approximately $1300 to$1500.BlackJack Silver Seal 300 at (B)Lowe's is solvent based and sells for $63 ($68 tax include) per 4.75 gallon can which would total just under $1000. I could do this http://www.builditsolar.com/Projects/Co ... teRoof.htm for about $30 (LOL). I e-mailed the guy and he said it lasted 2 years and through 2 winters and may have been more but had a new roof put on. My fear is that it may accelerate mod-bit and seam detioration, although it shouldn't as it's alkaline based. Also need to wear mask, googles and gloves as it has silica in it.

If I knew for sure that aluminum coating it would incease it's life by 3 to 5 years at the cost of $200 to $300 a year I would say it'd be well

worth it. Unfortunately, that is the dilema as there is no garauntee it will. I would actually like to coat it for two reasons a) UV protection and

likely extended life b) asthetically it will look better as the overflow on the seams won't stand out as much as they have since it was installed.

there's a few houses on my street that have recent modbit roof and looks much beter than mine. Most likely is peel and stick cap sheet over a mechanical or peal base sheet.

"It's peeling in the corners because of the flashing material. Forget aluminum gravel stops/drip edges/flashing details. Mod bit doesn't weld to aluminum worth a darn. (I'll modify that to, it'll weld sorta ok if you double prime it and go overtime on getting the welds tight, but I'd still be watching it every year.)You want minimum .032 galvanized; if you don't want shiny metal, use Keynar coated material (available in the usual brown, bronze, white colors). Double prime this stuff, and it'll hold forever. Well, almost forever."

To clarify: are you recommending I purchase, install and double prime the drip edge (Keynar) now, then lift and reattach the existing cap sheet to it using adhesive cement. Or, are you recommending that when it's time for a new roof?

"What about venting? What's the roof structure? Is there an "attic" in there? All that magic membrane that keeps the water out also keeps the water in; I have a hard time imagining a single turban vent does much, but I could be wrong."

I understand about trapping mositure and have read some post about elastomerics causing issues. My home was built in 1958 and decking is 12" planks with approximately 1/8" or 1/4" gaps in between nailed to rafters 16 inches apart. The wood looks good from underneath viewed from inside (no ceiling) the attached garage. There are 2 turbines 20 feet apart, no gabel vents, and very small crawl space under peak of roof (little attic room).I had a few roofers out for estimates on the repair pics I posted, they said that the roof decking is attached much better than newer homes and the wood is of much better quality as well. New wood sold at big box store here in Floida is total crap for the most part.

Thanks for all the replies so far and look forward to more responses.

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Personally, I'd wait 'til I did the roof. You sound like a hands on sort....check it periodically and repair if necessary. The beauty of mod bit is it's accessibility; if you know your way around a torch and trowel, you can repair it easily and forever.

So, no attic. If it all looks OK, it probably is.

Agreed on the punk wood sold nearly everywhere nowadays.

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I am moderately handy and leaning a lot about roofing materials and issues through great sites as this and others around the web. Trouble is lately I feel I might be over-thinking the process through to much Internet researching.

I have never tried using a torch, but comfortable using cement, trowel and mod-bit roll.

My son and I just finished peel and seal(ing) the aluminum patio roof, 3-coursed an area of concern and asphalt primed some of the (top) of exposed drip edge and cap sheet to ready it for adhesive cement. Probably over-kill but at this point I am settled on function vs. looks. Thanks again for your responses Kurt.

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......I feel I might be over-thinking the process through to much Internet researching.

Good observation. It's really not complicated.

Go to the mfg's. sites, read up.

Try to avoid DIY boards and orange aproned aisle dwellers advice, you'll do fine.

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Well, curiosity got the best of me today and I broke down and bought a gallon of silver seal 300 for a whopping $20.

I used it on the top of the cement/adhesive (3-coursing) used during the recent repair two months ago and on areas near intakes and vents that granule loss. Hopefully, it will help it last longer. I also used it near the peak over the alligatoring and will evaluate it every 6 months to see if has any benefit.

I can see where aluminum coating may work well with non-granulated cap sheet, but for granulated I can't see it helping much and would take a lot more to cover compared to non-granulated. So, now I know the answer to the question that was eating at me.

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And it only cost you $20. You're doing the best thing, i.e., keeping an eye on it and monitoring the effects of your incremental repairs.

Personally, I love mod bit. It works. It's easy. It holds up remarkably well if you keep the UV off it.

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When it comes time for a new roof I want to add a pitched slope over the flat deck.Possibly go with metal througout or in combination. Please share your recommendation for type of (new) roofing.

My Mom is retired and living in a retiree community in Florida. She's got a metal roof on her home. She's one of the only folks left in her development that hasn't added another roof above the first. Just about every house in there has had a new sloped roof framed up over the top. Most are composition but a few were tile and some were metal.

Her roof was leaking. She was about to go out and blow $15K to have a new roof framed up over her home. I told her not to do it, called my younger brother and told him to get down there, got on a plane and flew down there. In four days we stripped that old roof using the same stuff they use to strip the paint off of aluminum aircraft skin, burnished it, taped up all of the seams with acrylic-faced peel-n-seal, and then went over it with several coats of a white acrylic coating. It formed a hard acrylic skin that was very durable. We bought the stripper from an aviation maintenance supplier and the peel-n-seal and big five gallon buckets of that acrylic from a place that provides supplies to companies that do services on mobile homes. Total cost was less than $500 including my round-trip ticket from Seattle to Tampa.

I guess it's been about four or five years and she hasn't had any trouble with it. The white reflects well and keeps her home cooler than it used to be. Since the initial peel-n-seal used on the seams was about 35 years old when we stripped it and she's in her 80's, she wasn't too concerned about longevity of the stuff we applied but I think it's goint to hold up at least as long as the original. When the rest of the thing collapses from old age that roof will probably still be pretty good.

She has a handy guy climb up there once a year with a mop, a bucket of water and some spic-n-span. He cleans the dirt film off, rinses it off with a garden hose and it's good for another year.

ONE TEAM - ONE FIGHT!!!

Mike

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I didn't know peel and seal has been around so long. I told my son the white peel and seal we laid down should last about 15 years, if it goes 35 it will most likely outlive me. 10 years ago when I was getting estimates for the roof I was told I basically have two choices due to the low slope: BUR tar and gravel or Modbit. When I bought the home it had a tar and gravel roof and I hated mowing and trimming over pebbles that had fallen from the roof, so I went with modbit and glad I did. Looks like I have a little bit more fascia and soffits to fix, but I can"t complain too much as it could be worse after 10 years.

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Maybe ABC stands for Always Bullsh!$ Customer. I am kidding they didn't try to push any products on me and actually discouraged use of coatings for granulated cap sheet. I showed them the alligatoring pics on my cell phone and they probably didn't zoom it in enough. The cracks are slightly deeper than the granules.

They did mention a system named Hydro-Stop and a man I can contact if I am interested. I've seen videos on youtube about it and most were made in Chicago. If anyone has any first-hand knowledge or recommendations on Hydro-Stop, they are much appreciated. I will say I am very leery about any claims of miracle roofing solutions as manufacturers will always point to poor application if issues arise. Good luck suing a contractor that applies it as they will claim they followed the manufacturers suggested application technique, and the only person who ends up getting paid is the lawyer you might use.

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Maybe ABC stands for Always Bullsh!$ Customer. I am kidding they didn't try to push any products on me and actually discouraged use of coatings for granulated cap sheet. I showed them the alligatoring pics on my cell phone and they probably didn't zoom it in enough. The cracks are slightly deeper than the granules.

They did mention a system named Hydro-Stop and a man I can contact if I am interested. I've seen videos on youtube about it and most were made in Chicago. If anyone has any first-hand knowledge or recommendations on Hydro-Stop, they are much appreciated. I will say I am very leery about any claims of miracle roofing solutions as manufacturers will always point to poor application if issues arise. Good luck suing a contractor that applies it as they will claim they followed the manufacturers suggested application technique, and the only person who ends up getting paid is the lawyer you might use.

Right. I'd be leery of any new roof coating product. I'm more inclined to just replace a roof covering that's expired.

Marc

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