Metal Sheeting Leaking

[jhambley]

I've heard from several people now that there are only two kinds of metal roofing/siding, ones that leak, and those that are going to leak.

Is this true? Is it because the screws loosen up?

[MountainDon]

That statement could be made about any building product.

[jhambley]

So do you have any personal experience with metal sheet roofing/siding?

[Ndrmyr]

Considering how many 100 year old homes I've seen with metal roofing slatered with aluminum mobile home roofing paint still standing, I would say that their average is pretty good. Condensation can be somewhat of a concern unless properly addressed, but, I have two visible screw roofs and they are as dry as a bone.  Frankly, looking forward given the future cost of asphalt shingles AND the future cost of disposal, I think a metal roof is one of the finer choices.  In most cases, it is the last roof we will purchase, it's slipperyness is great for reducing snow load, and with a simple roof design is easy for a DIYer to master.  Perhaps it's finest quality is it's weight.  It is as light as a feather compared to shingle load.  It takes many years for the washer on a screw to fail, especially since the actual sealing portion is compressed and isolated from UV and Ozone.  Standing seam should be a longer-life product, but, given the cost differential, most of us opt for exposed screw. Perhaps the greatest drawback, if you need it, is roof accessability.  Most of us will clamber on a shingle roof, you will be less likely depending on your roof pitch to do so on a metal roof.  In this respect, I like the exposed screw, since you can use them for traction.  If you follow manufacturerers installation instructions, I think it unlikely that you will experience leaking.  When it happens, it is like most things, installer error.  Unlike assembling a tricycle at Christmas, reading the instructions for roofing products is essential.

[hpinson]

It is mainly because the screws loosen up and the washer seals fail after a (long) time.  If done properly intially, these issues can be addressed, that is, screws replaced after 15 years or so.

I just had to do some repairs on one that is perhaps 30 years old.   The corrugated metal roofing was screwed to 2x6 trusses, with no plywood/ tar paper in place.  It was bone dry for many years.  Over the years most of the screws loosened and washer seals dried out and failed.  The holes became such that for many they could just not be screwed back into the original hole and tightened. Either a longer screw was needed or new holes used and old holes patched. It was not done so well in the first place, as holes are out of align and some miss the frame studs althogether. Because of how the screws were placed, the wind has a tendancy to pull parts of sheets up. Yes, after 30 years it leaks, though amazingly not so much.  Condensation does not seem so much of a problem in my dry climate, though I can see how it could be in other areas. I really need to replace the whole thing, and that is barely worth it, considering the structure it protects.  After repairs I can say that it leaks quite a bit less.

That said, if the metal roof was done right, (there are very good instructions available) It seems like it should hold up as well or better than shingles.  I think it would be hard to beat a professionally installed seamless metal roof.  The corrogated stuff is easier to self-install than shingles.  And the metal appears to have some scrap value. I'll definitly be using it again in different contexts.  It has a great, classic look too.

[MountainDon]

I don't have any old metal roofs. One is about 7 years old, another about 4 years and another has just been installed. I was told to be careful and to not screw the screws in too tight; to not squixh the bejeebers out of the neoprene rubber washers. When the time comes to tighten.replace screws because of loosening you can go up a size in diameter or get a longer screw.