Barn roofing

Was reading about this subject on another forum earlier in the month. We are putting in a bole building. The one topic that really gets people going with the opinions is whether to use a metal roof or traditional shingles. I like the look of shingles but was inclined to go metal because I thought it would last longer. Half the contractors quoting agree with that. The other half are pointing out that the metal roof has a lot of exposed fasteners with rubber washers on them and they say these will not last in the hot sun and that then the holes will be free to open up with expansion and contraction of the metal. This will let water in on your trusses and eventually rot them. This is a really hard choice to make.

Basically, no contractor wants to put metal on trusses with or without a barrier. The two options given are:

1) Traditional roof with a higher end shingle, light color to reflect heat, over OSB.

2) OSB roof covered with a vapor barrier, metal over the barrier. In theory if you have a bad washer water runs down the barrier I guess.

Just wondering if any barn owners could help me out. I need to make a choice this week to get on the list for the contractor.

On my wife's Riding Arena I had built 10 years ago, I had them put down osb, 30 lb felt, and screw down the steel. The osb and felt eliminate all the condensation and most of the noise when it rains. Costs a little more to do it that way, but I will never have to replace that roof. Shingles I would be half way thru their useable life already.

Whether the metal roof is attached to steel framework or wood framework the screws with the rubber washers will last very well. I have a building built in 1986 in north Texas and it holds up to the heat very well. The only problem you might experience is if the building isn't insulated. During damp weather condensation will form on the roof on the inside and rain inside the building. The building I have I installed fiberglass panels here and there for a skylight and water drips from them. The rest of the roof is insulated and there is no problem.

With a shingled roof keep in mind the roof is heavier and needs a lot more framing to support it than a metal roof. This adds a lot to the cost of doing shingles.

I would use metal building insulation for a vapor barrier. It looks nicer than OSB and makes the building a lot cooler in summer. It comes in rolls 4' to 6' wide.

I think the bigger thing with the rubber washers is nails versus screws. Nails not so good, screws alot better. Nails work thier way loose. Once it is loose the rubber washer is no longer tight, will leak and start to deteriorate the washer along with what it is nailed to. Screws have to turn to come loose. They generally don't, and the washer stays tight. Rain water only gets to the edge if it stays tight and washer lasts alot better. I wouldn't be afraid. Very common in my area and seems to be the preferrance. Not as big of problem as shingled roofs going bad and leaking before they are replaced.

I( used a product called "Insulboaed" under the tin.

I put metal on a small barn, and intend to put it on a larger barn and my house. I don't think that there is any question that metal lasts longer. I think a lot of folks, including contractor's, are afraid of something "new". I haven't seen a new farm structure around here with shingles, ever. One well known farmer has built about 10 large structures, right off Grand River, between Howell, and Fowlerville. They are one of the larger farmer's in Michigan, and do things right.

There are many types and brands of steel roofing with different screws, and then there is standing seam roofing. I haven't priced it, I know that it is substantially more, but there are no exposed screws or nails so it is good for a lifetime. You really should check into it.

That would work if there isn't an insect problem. In my area ants get into the insulboard and eat it away. The insulboard has an R rating about half what the metal building insulation has but is enough to stop the condensation problem.

My take- we'll sell you a shingle roof and we'll be back in 10-25 years to sell you another one, BUT if we sell you a steel roof and install it right as a customer you're dead to us, you will not need our services unless you have a fire or storm damage. I look at it this way- when the roof has to come off do I want to go to the landfill and pay dearly (if the EPA/Government will even let you landfill shingles) or do I want to go to the scrap yard and get a check? I'm not a big fan of "green" but I do believe in making responsible choices when you build or repair.

I am not a carpenter but there is a barn on this farm that got a metal roof in 1956. It was the lighter corrugated stuff as well.

In 58 years the nails (not screws) have been tighten with a hammer once. One sheet of metal has been replaced that blew off in a major wind.

And it still doesn't leak.

I'll take a metal roof any day.

Shingles these days are junk.

Gary

Dave These parts (Tennessee) about all you see on out buildings is metal. Most is applied to strips with a new product called microfoil. It is a vapor barrier and insulation all in one. No need for the OSB. The thing with the screw/nail is used good grade screws that have a washer over a neoprene washer. We use cadium plated screws so no rust and the neoprene washer does not dry up and get hard. Have some metal roofs on wood structures well over 30 years old with no leaks.

I would look at older comparable buildings in your area and see how they were built and how they are holding up. Livestock buildings have moisture problems and don't last forever no matter what you do. But a building for machinery I don't see moisture as a big issue. (at least not an issue you can control unless you heat and cool the building) And If I could not get a contractor to build what I wanted I'd fire him quick.

Metal.

The rubber screw gaskets (screws, not nails) last longer than the joke of an asphalt shingle these days.

Barriers and such depend if you heat the building.

Just had to replace a few nails with screws last year, on the metal roofed building dad put up in 1964. I'd guess we got the money's worth out of them?

Paul

If it is a smaller shed and you want the regular shingle look, the metal shingles like Decra brand are really nice. Spendy tho.

Paul

A rubber gasket won't last but a few years in the sun. A NEOPRENE gasket will last a lot longer. Remember the old twisted lead head nails? I had a couple of corrugated galvanized roofs with lead head nails on this farm. The oldest, built in 1958 was re-roofed a couple of years ago. Most of the old lead heads were too tight to get a flat bar under but the lead wasn't sealing much anymore. Of course they were nailed on the top of the ridge (black thumbnail!) so that helped cut back on the leakage. Jim

So, read your responses to my wife last night and we discussed it at length. I guess we are going to do the metal roof. Even if it were to go south on me, I think it will be easier to fix than a lot of shingles. I had good shingles put on the house a few years back and they have worked out good. Old ones lasted 20 years but were rough when they came off. Makes a mess too. When I bought the farm I found a farm dump where they had been dumping shingles for decades. I sent three Bagsters completely full to the dump and then when that started to add up I switched to black plastic contractors bags. We sent two huge bags a week out with the regular trash over two months. All told, about 5-6 tons of shingles by my math. At least you can SELL a metal roof when it goes bad!

Have you tried actual pole barn builders, not general contractors?

Around here pole barn builders just lay purlins across the trusses and nail the steel directly to that. Optionally you can have a layer of insulating foam sandwiched between the steel and purlins to prevent condensation inside.

Lots of new steel roof options out there today since shingles are all junk now.
Standing seam been around for YEARS has no exposed fasteners as does the new metal shingles. Looks like shingles but is made of metal. Interlocking panels with hidden fasteners. Saw an infomercial on TV they look neat but are expensive.
Then maybe some still does slate ? I see some REALLY OLD roofs and they still look great.

Guess I'd better get up in the rafters and have a look. Roofed in 2000.

I built an indoor riding arena with attached stables and a lounge/apartment (23,000 sq ft)
an roofed it with shingles...big mistake. The shingles were good for the first five years and then it was a continual nightmare getting shingles replaced. Finally, this year, I replaced everything with painted steel...should last longer than I will.

Dave, It sounds like you have already made up your mind and are going with metal.

Well I thought about you when I picked up a 5 gallon bucket that was upside on the ground for a few days. We've have dew points in the 70's and night time temps below dew point. Inside the bucket were drops of water, condenstation.

So if you are going with metal, I would recommend trusses on 2 ft for snow load. OSB instead of perlins. That way if you do change your mind, all you will have to do is remove the metal and nail shingles. Locally a roofer is advertising on TV a 100 year metal shingles that look like regular designer shingle.

In my younger days, I had an all metal shed. That's when I learned to hate metal roofs. The condensation inside shed, everything rusted, wasps would find their way in the shed because the roof had bends in it.

I looked at many pole barns before I decided I wanted to put an end to condensation, not by using a plastic or foam barrier that birds could carry away. I also noticed that all the metal pole barns have no overhangs. I wanted a 1 ft vented overhang, no rain gutters that I would have to clean, and most importantly, I didn't want rain dripping from gutters on siding creating green mold. I also wanted light panels installed under eve so the pole barn wasn't a dark cave.

So if you are going to put metal over OBS, I would strongly recommend putting something between metal and OSB and making vented eves. I even have a vented ridge, along with a 1500 cubic ft/ min power vent. I have yet to have rust or condensation. Even park a snow covered truck in pole barn in winter, no condensation. No floor drains either, don't need them. Snow melts and drys up on it's own. My barn isn't insulated or heated. Just used to keep things out of the rain.
George

Yes. In addition to the accounting practice, I was a GC and built houses at one time. These contractors are all pole barn specific guys.

Thanks George! Yes...OSB with a vapor barrier over it. Metal over that. Pending review of the warranties involved to make sure it is in spec for those. I will not have a metal roof exposed to moist air. I don't need an ice cave in January followed by early rain.

Be sure to look at standing seam metal roof. No exposed fasteners.

Hope you think about eve vents and ridge vent too. Ventilation is the key to staying dry.