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Looking at building a 20x20 garage and I'm considering metal roofing. Not overly popular up here but getting more so. Any thoughts on using this vs asphalt/fibreglass shingles? I am a decent roofer and could lay shingles myself so no labour cost. Same with metal roofing I would install it myself after learning installation technques.

How much prep is needed? Specifically 1/2" plywood sheating needed or just strap it off? That would affect cost big time. Also salt belt up here and constant salt in air from ocean and road salt...corrosion problem?

Not much help here from building supply companies as they contract it all out. Got my first quote from metal roof suppler and it ain't cheap...

Any thoughts appreciated.

Personally,I've never been a big fan of it. My neighbor did his roof and was happy with it. I'm just finishing up a 2 story home and the home owner wanted metal....I'm still not a fan of it but hey, that's just me. Buy you some 30 year architect shingles and forget about it. Yes, the roof was expensive but his little Blonde wanted it!

....now if I ever build another shop I'll put the galvanized roof on it like the roof on my moms house that was built in 1948 and wasn't re-roofed until my niece wanted something "different" about 1987. I just like the sound of the rain pounding on it like I use to hear at night when a kid.

I did a metal shake roof. I'm very happy with it. It is supposed to outlast me!

http://www.metalroofing.com/v2/lightbox/uploads/regular/2390.jpg

They didn't sheet my roof, they laid it on the old 1 X 4's. I believe they attach a 1 x 2 strip and then the shingle is nailed in to it sideways. Supposed to be good to 120 mph wind.

BTW, not my house. Just an example of the shake. I can get pictures in the daylight tomorrow if you are interested.

Built a new house and hanger in 1985. 30 year GAF Timberline
asphalt shingle on the house and clear cedar siding. Morton
steel sheeted pole building for the hanger. Replaced asphalt
from storm damage once, many broken shingles over the nearly
three decades we lived there, house was way over due for a new
roof when we moved a few years ago. Had painted it a couple
of times and it needed another paint job before we could sell
it.

The all metal hanger.....was like new and probably would have
gone another 27 years, at which time I'm not gonna care what
happens to anything.

dg

Randy,

I like metal roofs; however, I know nothing about their durability in a salty environment. I have no metal roofs, because I did not have the $$$ when any of my roofs were installed. I have helped install the pre-fab metal roof panels on friends' roofs.

I had a friend in college who dropped out to install and repair standing seal/seam roofs in VA. Some were well over 100 years old. This was far from the ocean in the Piedmont region.

My college uses terne-coated stainless roofs (and siding). Some is over 50 years old - no maintenance - installed by union-trained crafts-people.

This seems to be an informative and "even-handed" primer.

Down are way galvalume metal roofing is cheaper than 30 year asphalt. For the best screw retention, the engineers at the tin roof manufacturers recommend that a solid 5/8 plywood sheathing be used, at least for a house. I think you would be okay using 1x4 lath strips on a utility building, but you may experience some condensation drips.

Installation of tin is fast once you get the first sheet properly aligned with the roof.

Steep pitched tin roofs are scary to walk on compared to asphalt.

not sure how close you are to ocean, but snow removal looks easier (which would have been nice last February)

some of the new roofs have a good paint,so they might hold up in that environment

I will ask around when I am in midcoast Maine

Here are some pictures of a small standing seam roof we did not long ago.
https://flanamullegan.wordpress.com/
As for special tools it could all be done with one set of adjustable seaming tongs (like hand held metal brake/tongs) https://www.stortz.com/product/stortz-adjustable-roofing-tong/ I just picked up a pair at a junk shop for $15
And a seaming iron and wood mallet for completing the folds/seam on the roof. https://www.stortz.com/product/ese-hardy-tool/

There also all sorts of nice fancy tools but those are all you really need for a basic roof.
This design for completing the seam on the roof has been around for I think over 100 years, I've picked up a few at junk shops quite cheap though new ones are anything but. https://www.stortz.com/product/444-a-burritt-seamer/

We used 24 gauge galvalume that came in a large roll, 10 squares, and cost ~$800 delivered. Weighed a lot, moved it with the forklift. Advantage over using 10 small rolls is less waste, lots less depending on your pan lengths.

Not sure how suitable galvalume or even galvanized is for your location but they do offer stainless roofing suitable for standing seam, and while more expensive I expect would be great in the salt air.

Grigg

Grigg
Is there anything you don't get involved with and learn from it?
I'm watching this great thread and hope to install a steel roof on our house next year.

Thanks
Don

Well, I'm trying to keep drywall and painting off that list..

Thanks,
Grigg

I guess it depends on where you are located and the climate there, but metal roofs are very popular here.

I have a 25+ year old metal (Galvalume Multi-Rib from Metal Mart) on my house. It is screwed to 1/4 lathe set on 12" centers. No one has walked on the roof, not even during installation, except at the ridge. It is on a 5 in 12 pitch.

My shop was built in 1974. Steel building with painted sheet metal. The only leaks in the roof are the fiberglass skylight sheets, which have deteriorated. If the leaks continue to get worse, I am going to screw a piece of sheet metal over each of them.

As for what to put metal roofing on I think skip sheathing is best. Solid sheathing won't allow it to breathe and could corrode from the back side.
We use approx 1" by 3, 4, or 6" and space them to suit.
Part of the that last roof was actually on 1/2" OSB and made the effort to still put skip sheathing on top of that so it could breathe.

Grigg

Putting on shingles was how I got the idea to go to college. Roofing in Utah under the August sun, then hammering roofing nails in February, with a 20 MPH wind chill. College seemed like a good idea for sure. I put a 30 year fiberglass architectural type roof shingles on in the early 1990's. It needs to be replaced now. The sun kills shingles. The roof is properly vented so that is not the issue. Across the street from me is a 50 year old aluminum shingled roof. The color is gone. The roof looks great. It unloads snow in the first hour after the sun hits it. It has had no maintenance, no leaks and no help in the entire time it has been in place. If I ever do another roof it will not be shingles.

My shop has a steel roof. The previous owner used steel and when I doubled the space I used steel. The old section has three small leaks when it rains in torrents. So far I've failed in several attempts to find the leaks and repair. The new section, about 10 years newer than the old, has no leaks at least so far. If starting over again, I'd likely use steel again.

I've been in Commercial roofing for 18 years. Whatever you decide, do not choose a 26/29 gauge exposed fastener panel. Being in the salty environment I would do a lifetime grade of dimensional shingle with plenty of ventilation and in a black color. If you really want a metal roof, choose a concealed fastener standing seam panel with a minimum seam height of 1.5". 22 gauge galvanized (or ZAM alloy which is showing a lot of promise). If you have hips or valleys I would do full sheathing with FULL COVERAGE of high-temperature ice & water shield.

Chad they quoted me exactly that - a 29 gauge exposed fastener panel. $1200 for the shed for materials.

I think I'll go conventional with plywood sheathing and decent shingles. The cost looks to be about the same. I am concerned about corrosion and I have seen some rust forming on older installed metal roofs here.

Lots of good information in this thread and thanks for the responses.

29 gauge feels like paper in comparison to something in the low 20's. like ice cream and everything else these days they sell less material in the same package for the same or more money.
Hardly seems worth the labor to put such thin metal on.
I had to ask around just to get 24 gauge and would have preferred a little thicker yet.

Grigg I am concerned as well about the 29 gauge..it seems to be the standard here..seems like heavy foil...

I wonder how something that thin holds up to hail out west(not an issue here, very rare - we get hurricanes...)My buddy bought a Porsche Boxster cheap in Alberta due to hail damage, and the car looked like a golf ball! He got a lot of the dents out but even that metal was a lot thicker than 29 gauge roofing....

29 gauge is the standard around here. It a higher tensile strength than the 28 they used to sell. It holds 15% more weight than 28ga before it deflects. I've been putting this stuff on for over 40 years, just did one again yesterday. If you think 29 is flimsy, try putting on 34 gauge as I did in the Dominican Republic last year, with purlins spaced 4' apart. But I would be cautious putting steel on in your environment, look around and see how other steel roofs are holding up.
One other thing about steel, snow will slide off, even on a 4/12 pitch.

Yeah, it is a challenge to keep gutters together.

Smart choice. I am a proponent of BLACK colored lifetime-grade dimensional shingles so long as you have good ventilation. People think I'm crazy but they just last and are a good value. If you have algae concerns, put a strip of copper under your ridgevent, protruding out a couple inches. Rain water washing over the copper kills the algae. I would do full ice & water shield or synthetic/titanium underlayment and not 15/30 lb felt.

Our company installs just about every brand of metal panel on the market from Centria to FlexoSpan. You can get stainless standing seam panels from Flexospan and some other manufacturers but they are expensive and tough to seam. They truly last forever but it doesn't mean they won't leak if your flashings aren't done properly.

http://duro-last.com/black_roofs_vs_white_roofs

It is interesting to note that FlexoSpan gets high LEED ratings, but maybe not with BLACK color.

We get moss up here Chad, any experience with adding zinc strips on the ridge vent to help beat this back? I used to be a fan of trees, not so much anymore, at least around roofs. I've opened the area up but still get moss.

Also, I'm old skool tar paper. What is the scoop on this new roofing underlay I see around? Better than the old underlay?