Metal Roof Question

[Mike OMelia]

Hope I do not get in trouble asking this question here, I just do not know where to ask and trust. I have a cabin with a very nice looking, plain metal finish roof. Looking at buying a pole barn garage package to install alongside. Pole Barn folks tell me unpainted metal roof will rust out in 10 years. What is on my house? Are there plain metal finishes with 30-40 year warranties? Or is my roof painted, and I just do not know it?

[Ed Aumiller]

Most metal roofs a few years old are painted... Galvanized metal roofs if painted about every 10-15 years (or longer) will last well over a hundred years or more..
The paint is most often silver, the same color as the metal, and is VERY thin and very easy to apply..
Even an unpainted metal roof will normally last 40-50 years unless leaves or something accumulates on it to hold the water in one spot, especially if it is very flat metal roof.
The newer metal roofs have a baked on painted surface which will last many lifetimes...

[Jack Frederick]

Hope I do not get in trouble asking this question here, I just do not know where to ask and trust. I have a cabin with a very nice looking, plain metal finish roof. Looking at buying a pole barn garage package to install alongside. Pole Barn folks tell me unpainted metal roof will rust out in 10 years. What is on my house? Are there plain metal finishes with 30-40 year warranties? Or is my roof painted, and I just do not know it?

I just installed metal on my well house. It is small, but I went with corrugated core ten (606a) material. It is 22ga. I think you have to look at each specific metals thickness before you can say it will last, or not, and a major determinant will be gauge. Some of the plain galvanized rooting is 26 or 28 ga. They should list it as “tin foil”.

[Bill Bukovec]

The places around here that sell metal roofs say you have the option for a 10 or 40 year warranty on the paint.

[Tom M King]

Google "galvalume warranty" and see what you can find. It's an aluminum- Zinc coating, similar to galvanizing, and what comes on the rolls of metal that metal panel manufacturers use, not including the cheap 5V tin you can get in the box stores. The company that I buy metal roofing from only guarantees what Galvallume they carry for 10 years, whereas you can get the "painted" (not really paint, but a fancy coating) with a 40 year warranty. Other metal rollers may vary, but none of them manufacture the metal they use. It comes coated on the rolls they buy.

Don't think that any brand name of roofing metal is better than another. There are many more rolling plants, than there are metal manufacturers. Most even use the same color charts, and color names. Buy from your closest rolling plant. Most of the cost of what you order from a box store will be cost of shipping, that's included in the product price. I can pick up from the one that I deal with, 25 miles away, and the price is almost exactly half of what it can be ordered from Lowes for.

It's also nice to cut out the middle man in placing the order, because they will custom make any trim piece like I want it. For instance, I did one roof with a really long valley, and they custom folded three pieces the length of their computerized brake that nested perfectly together. You can't do that just ordering valley pieces from Lowes.

[Mel Fulks]

One house we did mill work for had a stainless steel roof coated with ,I think,zinc to make it paintable. I think they call
it Tern coated. That's the best type I know of.

[Wayne Lomman]

Do you get Colorbond in the USA? It's zincalume plated steel with factory applied colour over the top and roll formed in a multitude of profiles. It lasts for decades. Cheers

[Jerome Stanek]

My barn and house each have a metal roof barn is 28 years old and still looks new

[Tom M King]

One house we did mill work for had a stainless steel roof coated with ,I think,zinc to make it paintable. I think they call
it Tern coated. That's the best type I know of.

Follansbee Steel, the company that made Terne coated, went out of business in something like 2011 or 12. The roll formed roofing steel put them out of business. I hadn't heard of it being put back on the market since then.

[Tom M King]

Do you get Colorbond in the USA? It's zincalume plated steel with factory applied colour over the top and roll formed in a multitude of profiles. It lasts for decades. Cheers

There are Many such companies here, under many different names, but it's all close to the same stuff.

[Tom M King]

This one should be good for at least another 600 years. This is the road side of a lake house I built in 1991. I was considering putting Terne coated stainless on it, but copper was about the same price at the time. I paid 90 cents a pound for seven 1,000 pound rolls of copper. Today, it was $10 a pound the last time I looked.

https://www.woodtalkonline.com/uploads/monthly_2018_08/copperroof.thumb.JPG.442c8da1e30f22b6bc887b8c755db cbf.JPG

[Nicholas Lawrence]

Very nice roof Tom.

I have always liked metal. I have a “flat” (2/12 or something like that) roof, and am told that is too low for metal. Also too low for shingles according to what I read, but a lot of my neighbors seem to have done that.

[Tom M King]

I have put a standing seam metal roof on a low pitch, maybe even lower than that. I don't know if the warranty is any good, or not, but it hasn't leaked.

The company I buy such metal from is in South Hill, Va. I don't know how far that is from you, but I like dealing with them a lot. I think the last standing seam metal I bought from them was something around $1.25 a square foot, but I picked it up myself.

The hip roofed porches on this house were not original, but they wanted to keep them(exact match on the back too). The slope is no more than 2/12, and maybe even 1/12. I put 24 ga. white standing seam roofs on them, and they have never leaked.
http://historic-house-restoration.com/sitebuilder/images/CIMG2126-595x462.jpg

[Al Launier]

https://www.bridgersteel.com/blog/5-types-of-metal-roofing-materials-pros-cons

[Mark Bolton]

We've put on quite a bit of classic rib metal and I will say there is most definitely a difference in quality from manufacturer to manufacturer. These pop-up roll formers that are the size of a trailer you tow behind a pickup are not capable of rolling the heavy stuff. Most all of it will be 29 gauge because the roll stock only comes from a few sources but the difference is in the finish thats put on the material. You'd be surprised the difference between some 29 gauge and other that has many coats of polyester prime and finish. Its really amazing. The cheap stuff you will waffle a rib instantly if you inadvertently step on one and you can feel the difference moving sheets around instantly

We have installed, and I actually have on a little house of my own, the galvalume color which looks like raw but it is actually coated and carries the warranty.

Im not really a fan of exposed fastener metal roofs but they are extremely popular here. Everyone touts them to last forever like the tin roofs of old but honestly they have the same cosmetic life span as good dimensional shingles and the shingles will look better when they are 40 years old than a painted tin roof will. Even with the modern finishes painted roofs will fade and chaulk in just a couple years and unlike the old farm house roofs not many today are going to enjoy their roof mopping on a thick coat of roof coating when it gets older. My prediction is you will be seeing a lot of tin roofs being replaced far before their warranty is gone because they either dont look good anymore or are failing due to installation issues.

We always tried as hard as possible to never set foot on the metal as it was going in and handled it very gingerly. Your basically walking on the hood of your car which you wouldnt do. Any scratch in the material is a guaranteed rust initiator. When guys gun slips off the screw and slams the nut driver down into the tin, rust initiator. Dont pre-drill your holes and get a little curl of sheet metal whipping around from the drill point screws, rust initiator. Field cuts, rust. All of which is not covered by warranty. Install directly over asphalt shingles (commonly seen here) likely a void of the warranty.

Im sure it varies from region to region but we had a conversation with a roofer who did a lot of tile roofs and he said they dont hardly use copper anymore because it doesnt last with the acid rain. Was always our go-to flashing for high end jobs. Heck around here you can barely find a commercial roof yard that stocks lead sheet or rolls anymore. Kills me to see people flashing off masonry and so on with aluminum trim coil or galvalume. Times change.

[Mel Fulks]

Interesting info ,Mark. But I think copper flashing that is failing is just too thin.

[Tom M King]

I think the longevity of exposed fastener metal roofs went down when 18v impact drivers became available. I get called to troubleshoot leaking roofs, and find the highest percentage to be caused by over-torqued fasteners. Also, the quality of fasteners has gone down since they started all coming from overseas. I've seen some fasteners less than 10 years old rusted out. You can find all stainless ones, in different sizes, and that's what we replace the rusted out ones with.

I won't ever put an exposed fastener roof on anything else though. All we've done for a decade, or so, is standing seam.

Here, you get the choice of 24 or 26 gauge in 40 year metal. I don't know what gauge the 10 year stuff is.

I have an exposed fastener roof on my barn that is still good, that was installed in 1980 with a cordless drill. It's the lightest color, next to white.

The companies that sell the roofing panels in a number of different profiles, like the one I mentioned in South Hill, Va., also use roll forming machines, but they're huge, computer controlled ones.

That copper roof that I built in 1991 just recently started to turn green, so I guess acid rain is not much of an issue here.

The linked article talks about how soft copper is, but doesn't mention that it comes in several different hardnesses. I doubt anyone makes a copper roof out of dead soft copper, which is pretty typical when you buy a roll of copper flashing. I do use dead soft for flashing old chimneys, but get 20 oz., instead of the common 16 oz. I have seen thinner, but don't remember what weight it is. I have seen the thin stuff eaten up by asphalt shingles. It's all sold by the pound, so the heavier the weight, stated in weight per square foot, the more it costs. That copper roof was 1/4 hard, which is fairly typical for a standing seam roof.

I have a page on chimney flashing on my website too, but not allowed to post a link on these forums. Click on my name, and I think you can find a link.

[Kevin Beitz]

My grandfather put a metal roof on my barn in 1935. Every 10 years it gets a coat of tar paint... Still doing a good job...

[John K Jordan]

...Pole Barn folks tell me unpainted metal roof will rust out in 10 years. ...

Maybe their cheap roofing material won't last. The galvanized roof on my barn was still in good shape after at least 80 years, maybe more, unpainted. I replaced it, not because of any rusting but to rebuild some of the support structure. I always use galvalume unless it's on a shed for the animals. Sorry, I don't know a thing about the fancy colored metal roofs.

[Tom M King]

I wish that metal that lasts 80 years was still available. I have one old house we work on that has one of those. It's 5V tin, but a very low carbon steel. It's very soft compared to later "tin". The lower edges have a sort of double chevron design stamped into the edge that keeps it down tight on the layer below.

I haven't found anyone alive that remembers when you could buy that type of tin new.

It's on a 1798 house, and the only other roof it's had on it was the original Cypress shingle roof. The galvanizing has long since left on the surface, but being low carbon, it has not rusted away to amount to anything, even though it's been brown rust color for several decades. The galvanizing on the under side is still in remarkable shape, and could pass for just being put up a few months ago.

I did find another old fellow that said he had some of the same stuff on some of his farm buildings, and he thought they were built in the late thirties.

The last time I remember being able to buy decent, galvanized 5V tin was in the 60's, and 70's. My friend, and I built an observatory, when we were teenagers in the 60's, with one of those tin roofs, and only in the past decade has it started to rust. My family sold that farm when I was in college, but I still drive by there once in a while.

The 5v tin panels that Home Depot sells can be cut with a pair of scissors, and I don't have anything I'd use it on.

[John K Jordan]

I wish that metal that lasts 80 years was still available. ...
The last time I remember being able to buy decent, galvanized 5V tin was in the 60's, and 70's. ...
The 5v tin panels that Home Depot sells can be cut with a pair of scissors, and I don't have anything I'd use it on.

The 5v galvalum is pretty good stuff, much heavier at 26 ga than the galvanized 5v most farmers around here get from the co-op. You can easily walk on it between the purlins. I can't imagine buying roofing at Home Depot...

JKJ

[Tom M King]

It's probably 24 ga. My metal company has 5V listed on the shapes they can form. I expect what you're talking about is probably that. They may have a 40 year galvalume, but I haven't checked.

The 24 ga. is sold for longer spans between purlins. The 24 ga. is noticeably stiffer than the 26 ga. It seems like it's twice the effort required to fold the edges of 24 ga. standing seam compared to 26 ga. Standing seam panels are folded around the lip of the drip edge.

[Mark Bolton]

I'm a masonry flashing junkie myself. I really enjoy how nice a well flashed masonry job looks. When people see the flashings possible with lead they are usually blown away.

I'm with you on exposed fastener metal and the roll formers. The company our metal came from have a facility with rolling lines that are the size of a house.

Standing seam is a different game and no one here will pay the price for the panels and fasteners alone forget about a true crimped seam standing seam roof. Even faux standing seem we can buy from the classic rib shops never can get any traction at twice the material cost and labor.

[Steve Rozmiarek]

Bridgersteel.com they have some neat "natural" finish options that might mimic the look you want. I'm going to try some on a coming project, haven't yet though.

[Mark Bolton]

Interesting info ,Mark. But I think copper flashing that is failing is just too thin.

No idea Mel but we are in a region called "chemical valley". It gotten better but..

[Mel Fulks]

We have one company in this town that will do standing seam and make all the "pans" ,or order and install the pans. I guess one reason they continue is there are so many old buildings owned by U.S. And state governments.

[Tom M King]

I'm sure I couldn't do what I do anywhere else. I don't do much roofing, but will occasionally take on one where the customer doesn't care what it costs, and is particular. First priority is that it's close to home. I very rarely go farther than 10 miles from home. That copper roof was on a spec house. This was for a neighbor maybe a quarter mile from home. I did their house too, that was really complicated with intersecting gambrels, and ten custom skylights with the curbs folded into the standing seam panels-can't find a picture of the house.

[Mel Fulks]

Follansbee Steel, the company that made Terne coated, went out of business in something like 2011 or 12. The roll formed roofing steel put them out of business. I hadn't heard of it being put back on the market since then.
Tom, I'm sure you are correct. I should have noted that job was about 17 years ago

[Tom M King]

I could easily be wrong about when I said they went out of business. I'm old enough now that it's like an old man told me one time that Christmas came twice a year now for him.

edited to add: I decided to do a Google search, to see how close my memory was (ends up it was in 2012, so pretty close). It looks like someone bought Follansbee Steel, and is now producing a bit different product than the rolls of metal that they used to sell:
https://www.constructionmagnet.com/metal-roofing-magazine/follansbee-steel-adds-charm-atop-island-home