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    Default OT? shop roof

    My shop leaks. It has always leaked. And every year the roofer comes and fixes some of these leaks - but it's a game of whack-a-mole, and it's gotten old. (Existing roof is metal with about a trillion exposed fasteners. Nobody builds house roofs that way why was it good idea on a commercial building???)

    I have in hand a quote to overlay the existing metal roof with a TPO system - some foam stuff (EPS) in the spaces between the flutes, then some insulating board over that, then TPO kind of heat-shrunk onto that.

    My question is:

    Do any of you have experience with or contact with people or buildings that have this treatment, and how has it worked out? (Or not worked out?)

    This is in Western WA state - so lots of rain, a little bit of snow, a couple weeks of intense heat, mostly mild weather. The roof has some pitch to it, it's not flat.

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    Quote Originally Posted by bryan_machine View Post
    My shop leaks. It has always leaked. And every year the roofer comes and fixes some of these leaks - but it's a game of whack-a-mole, and it's gotten old. (Existing roof is metal with about a trillion exposed fasteners. Nobody builds house roofs that way why was it good idea on a commercial building???)

    I have in hand a quote to overlay the existing metal roof with a TPO system - some foam stuff (EPS) in the spaces between the flutes, then some insulating board over that, then TPO kind of heat-shrunk onto that.

    My question is:

    Do any of you have experience with or contact with people or buildings that have this treatment, and how has it worked out? (Or not worked out?)

    This is in Western WA state - so lots of rain, a little bit of snow, a couple weeks of intense heat, mostly mild weather. The roof has some pitch to it, it's not flat.
    Something similar, retailer showroom, warehouse, admin HQ, technology of that era, back between 74 and 84 only resulted in the leaks taking longer to show-up - three days later - after the water had found a more circuitous path to an outlet. Over MY office for some years, actually.

    Solution was a roofer who actually sorted what had gone wrong, tore the whole mess off and did it over properly.

    I submit that - a fresh start - is cheaper than it sounds, off the back of saving on special materials and labour-intensive kinky-f**ckery done in situ, up atop an already aging and compromised roof for a base.

    Your one might be better served with standing rib where the fasteners & clips end-up UNDER the raised interlocks where the panels join. Nothing exposed. Built-in thermal movement management. No special magic in materials, sealants, nor layers of other "stuff" required. Keep your thermal managment indoors, UNDER it and simplify BOTH.

    Damned good wind resistance as well as rain, standing rib has, even on very low pitch. See "Florida" for proofs.

    Thought I was going to have to go that way at least for my long-problematic garage/annex/shop's uber low pitch. Hence researched it. Extensively.

    Still reasonably "in keeping with the neighbourhood" Reinke ribbed Aluminum "shakes" suit my over-plywood situation, but not your one.

    Have a recce. You can learn a great deal.

    THEN you'll need a roofer as actually supervises his ruffians to see to it they implement to design, not hit and run lazy!

    That part is harder!

    Band-aid patching, even on a grand scale, is seldom a genuine saving even when done well. Which is not assured, either!

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    Quote Originally Posted by bryan_machine View Post
    My shop leaks. It has always leaked. And every year the roofer comes and fixes some of these leaks - but it's a game of whack-a-mole, and it's gotten old. (Existing roof is metal with about a trillion exposed fasteners. Nobody builds house roofs that way why was it good idea on a commercial building???)

    I have in hand a quote to overlay the existing metal roof with a TPO system - some foam stuff (EPS) in the spaces between the flutes, then some insulating board over that, then TPO kind of heat-shrunk onto that.

    My question is:

    Do any of you have experience with or contact with people or buildings that have this treatment, and how has it worked out? (Or not worked out?)

    This is in Western WA state - so lots of rain, a little bit of snow, a couple weeks of intense heat, mostly mild weather. The roof has some pitch to it, it's not flat.
    I have 3 buildings with that system, no leaks, a common roofing system here. The screws have gaskets on them, gasket failure? loose screws? If the metal is in good shape I'd start replacing screws. Did your roofer gob mastic on the screws in the area of the leak? that makes the job a lot harder. How much does this new roof weigh? Normally a metal roof will have trusses 4' on center as a metal roof is relatively light. Do you have enough truss to hold another roof? Better get an engineer on this before you dive in.

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    Have you (YOU) ever actually determined why it leaks? Sometimes roofers take the lazy route and just slather goo over everything not really addressing the problem. If it has pitch, it sounds like it has to be leaking at the screws. The rubber gaskets do go bad after years of UV exposure, usually new longer screws are the fix for that (properly installed and not over tightened) Another problem may be screws installed in improper locations at initial install. I had a new metal roof installed on a 1.5-12 pitch roof 4 years ago, zero leaks so far, after suffering with constant leaks for 25 years from prev. poor installed metal roof disaster (before I owned the property).
    My advise is to determine if there is a fix to existing roof first before spending for a new one.

    edit: Moonlight beat me to it.....

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    Quote Originally Posted by dkmc View Post
    edit: Moonlight beat me to it.....
    Well "the industry" beat all of us to it, it is that common a problem.

    ISTR there are "families" of repair screws and gaskets that are specifically meant to deal with over-tightened screws into - one tribe, wooden battens- the other tribe, metal ones.

    Modern cordless tools with far better torque control than was once the case and a crew that knows the difference between "at right angles" and "at any angle convenient" does the rest.

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    Quote Originally Posted by thermite View Post
    Well "the industry" beat all of us to it, it is that common a problem.

    ISTR there are "families" of repair screws and gaskets that are specifically meant to deal with over-tightened screws into - one tribe, wooden battens- the other tribe, metal ones.

    Modern cordless tools with far better torque control than was once the case and a crew that knows the difference between "at right angles" and "at any angle convenient" does the rest.
    Mine were installed by an Amish crew that used old fashioned hand powered brest drills with the chuck removed and replaced by a screw socket.

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    I fixed a 7000sqr ft roof 3/12 pitch, used a urethane paint worked good but has a life of 20 years then its time to replace the whole roof...Phil

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    In my experience, it is NEVER a good idea to go over the top of anything that had issues.
    Be it floors, walls, roofs? Whatever? Getting rid of the old is the first step.
    As mentioned, your trusses are going to dictate your solution.

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    Basically boils down to the quality of the install and complexity of the roof layout. A good installer will return to inspect and patch the wrap job especially on flat areas.

    Sent from my SM-N960U using Tapatalk

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    We have about 10,000 sqft of TPO that's 15 years old on a flat roof, and going strong. Some branches that fell in a windstorm punctured the membrane, and the nice thing about that section of roof is the roofer didn't need to bring a kettle to fix it. The rest of our roof is Tar and Gravel (23 years old). Both are built up over Q-Deck with a few inches of foam insulation. We're just north of you in Vancouver, and both roof types seem to perform well for us. The TPO's silver-grey colour is supposed to keep down the amount of heat that's absorbed from the sun. Can't say that you can notice the difference in the different areas of the building, but they are not demised and we have ceiling fans, so it would need to be a MAJOR difference before it would be noticeable.

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    I have experience with TPO roofing over insulation and metal decking. The roofing is about 10 years old and has never leaked.
    I have also seen many metal buildings with metal roofing installed with exposed screws. There were very few issues with leaks, but the buildings were relatively young. I suspect that much of the issue is the rubber washers.
    Repairs with mastic or caulk often don't work well because most of these materials don't adhere well to dirty or wet surfaces.
    If the metal is sound, new screws and washers may be the way to go. If not, properly installed TPO over insulation could be a good option. You need enough insulation to assure that you will not get condensation at the metal roofing.

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    I prefer EPDM over TPO because there are no special tools involved

    That said, it was in an externally fastened metal roof building that was not new and we never had water hit the floor. Maybe some weeping
    This was a wood truss building with metal skin

    The steeper the pitch the less it leaks in general maybe the pitch is too low for that system

    If it was done by idjits in the first place and the screws are not straight to the surface, it may be frustrating to ever fix.

    I think someone here might have noted they make 'better' screws for these roofs

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    Technically, EDPM is one of the TPO class products!

    Just had my 350sqft shed roof re-covered with EDPM this week. 3/8" OSB was screwed on top of the original roof and the EDPM was glued on top of that with upstands and spouts formed from the continuous EDPM sheet. Not sure how it will perform, I'll get back to you after its 25 year guarantee period.

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    Quote Originally Posted by Mark Rand View Post
    I'll get back to you after its 25 year guarantee period.
    Could you make it 24 years? I'd like to get feedback as soon as possible...

    I'd love to do a foam cap with EDPM (or whatever) over my metal frame, metal roofed building. I'm a little (a lot) worried about moisture buildup, as there's already insulation under the metal roof, but it's a badly installed (pinched by purlins) fiberglass batting, nearly worthless as it stands.

    In fact, perhaps worse than useless, as the Tyvek inner layer allows inside and outside moisture to collect, then leak at a few seams. I may have to slash the Tyvek in order to prevent further moisture collection if a cap goes on.

    Any price estimates the OP gets would be of interest, please post roof size and thickness of insulation proposed.

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    I did a roof a while ago, it needed to be replaced.
    I replaced it with corrugated iron and underneath it air cell insulation, it looks like a fancy bubble wrap product but its really effective at insulating the roof from heat coming through in summer. gold foil one side ( to the iron ) and silver the other ( to the inside )
    Makes it so much cooler and is worth putting in. Although a bit above what is normally used.

    Yes Sheet iron is really common here it really is the standard in various different profiles, obviously different profiles have different spanning capacity between the purlins and you can look that up.
    If your not adding weight to the roof you should be fine ...as long as the roof is in good order structurally.
    It may pay to add another layer of insulation in between the purlins if your in a snow region, only thing is it makes it so much harder to find and fix leaks if they do occur.
    used tek screws with rubber seals on them.
    Yes any extra loading will need approval from a engineer to check the strength of the roof to see if it will handle the extra weight or not.

    I think its best to just do a roof properly and be done with it, do it once and it will most likely outlast you.

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    Quote Originally Posted by Mark Rand View Post
    Technically, EDPM is one of the TPO class products!

    Just had my 350sqft shed roof re-covered with EDPM this week. 3/8" OSB was screwed on top of the original roof and the EDPM was glued on top of that with upstands and spouts formed from the continuous EDPM sheet. Not sure how it will perform, I'll get back to you after its 25 year guarantee period.
    Maybe I have the names wrong, I thought TPO was one of the ones that is heat bonded

    EPDM wants to be installed over a compliant surface, I think your install was wrong. They used to use uhhhhh...recovery board? now usually iso board so that something as silly as hail wouldn't punch holes in the membrane

    I have never seen a professional install of EPDM over a solid surface.

    In theory EPDM erodes a few thou a year, so the thicker it is[I put .06 rather than 045 on my roof] the longer it lasts

    11 years in, the white ink printing is still intact and does not appear to be on an island, so maybe that is bunk

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    Some “Roofers” just want a sale and fly by night. I second the motion to get an expert or engineer to double check if you can support another roof. As for TPO, I live in Cincinnati and TONS of restaurants and apartment buildings I get on have the white TPO roofs. So far I have only really heard good things but I have seen some god awful installs using the white TPO.

    Do your research on the company’s your considering and for god sakes get multiple opinions!

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    If it were my shop, AND considering your locale, I'd replace the roof. With as much leaking as you have, you most likely also have dry rot that needs fixing. I'd strip it all off, fix the dry rot, and put a proper roof on it. Modern metal roofs should last at least 50 years with no problems.

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    Quote Originally Posted by gustafson View Post
    Maybe I have the names wrong, I thought TPO was one of the ones that is heat bonded

    EPDM wants to be installed over a compliant surface, I think your install was wrong. They used to use uhhhhh...recovery board? now usually iso board so that something as silly as hail wouldn't punch holes in the membrane

    I have never seen a professional install of EPDM over a solid surface.
    Correct, EPDM and TPO is different, not only in material but also how it's applied and adhered.
    EPDM however CAN be attached to a suitable solid surface such as plywood. Not sure about OSB because of it's surface structure and how well the adhesives can accommodate the large voids.
    I do have a 10 square ( 1000 sqf) garage with EPDM over 1 1/4" Advantech T&G using the same adhesive as on the foam insulation.
    About to have a 10,000 sqf ballasted tar roof stripped and re-roofed with 4" 2 layer insulation and EPDM.

    While I don't have any direct knowledge, all the people that are in-the-know have pretty much said the same thing.
    While TPO may cost a bit less than EPDM, the chemical formula used to make them have changed a bunch of times over the years, and is likely going to change going forward.
    Some grow, some shrink. Some crack, some bubble ....

    EPDM OTOH is as stable as it gets, and if the seams and flashings are properly installedm, they guaranteed to last 30 years ( talking .06 thick )
    They are also fairly easy to repair or patch if needed ( puncture, new roof penetration etc )
    BUT! You must keep anything oily or tar away from it!!!

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    The floorplate of the building is 8000sq ft (some inside 2 story offices raise the total footage but the roof is order 8000 sq ft) Measuring from the underside of the purlins (that I can get to) it seems to slope about 36" in 40'. So certainly not flat but nowhere near 4/12 sort of pitch.
    I was quoted about $8/sq ft (taxes etc change that. not sure about negotiating room. reasonably reputable roofer.)
    I've not called the engineer I know and who looked at the building when I bought it - yet - will do that soon.

    Have *I* examined the roof to chase leaks? No. And that's beyond my skills and comfort level (roofs, bad knees, ladders, etc.)

    It *is* the case that these folks have tightened down screws and applied various caulks (or so they tell me) and always got the previous leaks (including the most recent) to stop. But it's an annual thing. I suspect the initial install (not these roofers and not me and 30ish years ago) was done, let us say, very expeditiously....

    The building is cement and the beans and girders and purlins are all steel, as is the existing roof. "Dry rot" isn't so much an issue.

    I'll definitely noodle on this some more....


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