After 4 weeks of patching, caulking, tightening screws, and replacing valleys on a 14-year old green tin roof, with the help of a roofer and a homebuilder, I still have some “unlocated” small leaks. The house is a log home – square logs. The roof has 6 dormers, so there are lots of joints and valleys. The roofer and the homebuilder do not know anymore what to do. So… I am on the verge of ripping the whole thing out, and putting on a new shingle roof. That would be a $10K CAN expense (plywood + ice shield + shingles). Before I go ahead with this major expense, I am investigating whether a polymer coating, applied all over the tin roof’s surface, could be a smart option… or not. Would it cover and seal completely and hence “catch” the leaks I can’t locate ? Would it look reasonably good ? One product I read about is “Elastomeric Roof Coating” from Techni-Seal (www.techniseal.com). Has anyone used this product, or a smilar one, on a tin roof ? On a green tin roof ? Any advice much appreciated… on this or any other recommended solution. Thanks !
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Hmm, "unlocated small leaks"--the bane of all old roofs (or roof-owners).
One thing you can do, is to check the ceiling (presumably where the leaks are being spotted) for level. Often the leak "runs" along the ceiling/joists, until it "finds" a spot to drip down. The source for a leak can be in a much different place than in the roof above.
So, any a/c equipment in the attic? If so, have you checked the drip pan and drains?
Any attic or soffit fans, or other metal objects that could be condensing water vapor which then drips, and the drips wander off to leak through elsewhere?
CU (SeeYou) & Sphere are the 'resident' metal roof guys, so they can better speak to coating versus re-roofing. I'm just offering ideas that might be less costly (except in time).
You ought to fill in a bit more of your Profile (click on your own name, or the "Update Profile"), as that can help. Your post tells us this is in Canada, but not where--you could be a lot closer to winter/fall than some of us (about 6-7 weeks for me, for me). Since it's still A/C season here, and the systems have been cranking since May, any small incremental problems can go un-noticed until this time of year. Your climeat may vary.
CapnMac & SeeYou: Thank you both for your valuable observations and advice re my metal roof leaks. A/C is not involved, nor is condensation (eg, insufficient venting). Indeed, for days, we carefully investigated the leaks, i.e. where water came in and where it came out underneath -- one guy on the roof with a hose, moving it slowly, another guy laying down inside the overhangs --- and indeed travelled to come out at spots different to those where it came in. That led us to several specific spots where we tightened screws, caulked, and replaced 2 valleys (above 2 of the 6 dormers). This did stop some leaks, but there are still some, and some now seem to come out at different places. I suppose all the walking "up there" is not helping either. Anyway, "SeeYou" is right pointing to the "root cause" being a "bad install" (eg, too many joints, "underegineered" valleys/flashings/overlaps, some double-dip patterns "inverted", screws on the the double-dip joints not on the right dip, etc.). The metal (only 14 years old) is indeed fine, it is the "bad install" which had led to water infiltration - on the sides of the dormers, at the valleys above the dormers, along some joints (even horizontal joints!), and then around the screws which were "pulled up" by ice (over a few freezing seasons - these are 4-5 months long up here, near Ottawa). At this point, I've "had it" looking for needles in a haystack and patching, and I think I'll rip the whole thing out, install plywood, apply ice shield, and new asphalt shingles. My challenge now is to find a really GOOD roofer who REALLY knows what he's doing... (some don't know what they don't know) and to have this done before the freezing season. By the way, my garage has exactly the same type of metal roof as my house, it's of the same age, except that there is no joints at all ; that roof is still like new. My "aftertaste" with all this is that metal roofs (with "double-dip") are great if there are no joints (and ideally a steep slope), but that one is just "calling for trouble" if there are dormers and/or joints.
>>>>>My "aftertaste" with all this is that metal roofs (with "double-dip") are great if there are no joints (and ideally a steep slope), but that one is just "calling for trouble" if there are dormers and/or joints.Unfortunately, that's true with prefinished roofs and roofers still in the learning curve. Copper is a somewhat different story since solder replaces caulk and since the components can be custom fabricated to fit the situation instead of trying to shoehorn an out of the box component to fit. Good Luck.
"Let's go to Memphis in the meantime, baby" - John Hiatt.
http://grantlogan.net/
The only way a coating is going to stop "mystery" leaks is if you take the mystery out of it and find what's really wrong. Slopping some goop on is more than likely not gonna fix the leaks.
The type roof you have (my best guess) is not tin, but steel coated with some type of factory finish (polyester or kynar) and it must be exposed fastener if you're tighening screws. If it's only 14 years old and you're having to do all this work to it and it still leaks, you probably got a bad install to begin with. Also, this type of roof depends on caulk to seal junctions and penetrations rather than solder. The caulk ultimately fails.
If you can't find the leaks, I'd bail on this roof and try another, rather than keep throwing $ at this one.
"Let's go to Memphis in the meantime, baby" - John Hiatt.
http://grantlogan.net/
Honestly there is nothing good to say about tin roofs other than profit margins for unscrupulous contractors. Especially steel, since it is prone to begin rusting within a decade where the pait was cracked or scratched. I would say a good 90% of all the metal roofs are this cheap steel metal. A simple magnet test can tell you if it is steel or not.
I have written about these issues on our gutter contracting web site and http://dmr-gutters.com/pg/roofing.htm#Metal . You have a good idea to remove it and use the water and Ice sheild. At least I see the asphault roofs seem to go their promis and are much safer to work on.
Even if you can get a good attachment to the painted metal surface with the plastic coatings, years later they look quite terrible as the coating bubbles and peals off within a decade or less. Those coatings will retard your rust issues for the moment, but the sun will break it down swiftly, no matter what they claim. Forget about warranties. You would be hard pressed to push a claim through.