To sheath or not to sheath, that is my question.

[Dadnatron]

I am building a mid to upper level horse barn for thoroughbreds. I have the design and layout and am now trying to spec it as well as possible in order to get accurate and comparable bids. I've spoken with several contractors and there seems to be a wide range of what is best, necessary, or nice.

The barn is a T-shaped barn, long axis is 120' with small 14' portion jutting out from the center for a small aisle and additional space and central entrance. Overall, there is approximately 10,000 sqft of roof space, with a simple hip roof design at a roughly 9/12 slope.

My question is whether I should sheath the roof or not. One builder believes in using sheathing and Snap-Lock type metal roofing without any exposed fasteners. I admit I like this thinking a lot, however, the sheathing alone will add $10,000 in materials + labor and I don't know how much of a premium the metal roofing system would add.

Another builder believes it is best/adequate to simply use the Double-bubble type reflective roll insulation over purlins and lay the metal roof directly on top, securing with screws. This is how he built his own barn, which I've been in.

I'm not sure what the overall cost difference will be nor the benefits/problems associated with each comparably. Barn is in Kentucky. Air tightness is NOT an issue, again, the barn is designed to ventilate very well. But it will have some large animals in it so there 'could' be a humidity difference in/out at times, especially on very cold winter days/nights.

1. What is your opinion on whether it is worth it to sheath a barn designed to be well ventilated?
2. If no sheathing, is the 'Double-bubble' insulation useful/adequate?
3. Is there a 'heat' worry if there is no sheathing/ventilation of metal? ie will my barn become an oven?
4. How 'loud' is a metal roof without sheathing, in a rainstorm? Does the sheathing mitigate that issue to a useful degree?
5. Without sheathing, I don't think the 'invisible fastener' metal roof systems can be used. I don't want to deal with leaking screws for the rest of my life if I can reasonably address it now. Are these systems worth the cost?

 

[BLSXJ]

subscribing... cause a barn is in my future. and If I can learn anything from this I'll be happy

I plan on a metal roof, but have never seen/dealt with one with hidden fasteners.

I'd find the roofing material you want to use, and figure out what the manufacturer recommends.

 

[forgeblast]

When you say snap-lock metal roofing, is this stone coated metal shingles? If so do not use them, there are a lot of recalls on the stone falling off the shingle. I looked into them a few years ago.

 

[newbury]

<snip>
1. What is your opinion on whether it is worth it to sheath a barn designed to be well ventilated?
2. If no sheathing, is the 'Double-bubble' insulation useful/adequate?
3. Is there a 'heat' worry if there is no sheathing/ventilation of metal? ie will my barn become an oven?
4. How 'loud' is a metal roof without sheathing, in a rainstorm? Does the sheathing mitigate that issue to a useful degree?
5. Without sheathing, I don't think the 'invisible fastener' metal roof systems can be used. I don't want to deal with leaking screws for the rest of my life if I can reasonably address it now. Are these systems worth the cost?

I've only got about 5K sq ft of metal roof in northeast Mississippi.
Where I have insulation it changes the sound of a heavy rainstorm from unbearable to painful. Try and find a neighbor where you can experience a heavy rainstorm under an uninsulated metal roof.
I'm going to have to replace/rescrew about a 60x30 section because of leaking screws.
Also water condenses on the inside of metal roofs, uninsulated it may rain inside.

 

[Dadnatron]

This is the 'Snap-lock' roofing system that one builder recommends. He says the biggest issue he sees with metal roofing on barns is the leaks and drips around screws. Since he's gone to this style, he says he has not had any issues at all.

What is an 'economical' way to insulate (purely for pouring rain sound) a metal roof? Is there a way to do it without breaking the bank? I am not interested in spray foam under the sheathing, my wife would never go for that look.

Snap Lock Metal Roof Installation - YouTube

 

[newbury]

My roofer used foam that cam in large rolls.

 

[zzvyb6]

If it's filled with horses, keep in mind they give off LARGE amounts of water vapor. That means condensation, especially in winter. If you keep your hay in this barn (usually above the stalls), the hay will absorb a lot of this moisture and bales on the bottom layer will mold. Ventilation, mosquitoe, mice and bird entry considerations pay off in the end, too. My upper deck and roof is sheathed. This also helps keep the structural integrity sound. For a metal roof, the noise of roof panels 'itching' would drive me crazy. I have asphalt shingles and they stay put. Plan your barn for waterline repairs, manure management, arena viewing, pasture access, lockable tool storage, boarder lockers, safe electrical paths, a concrete main aisle, a toilet and wash stand, replaceable stall siding and kick walls and trailer access and storage. Have a separate building for tractors, mowers and leaf blowers (anything with fuel). Otherwise in 10 - 15 years it will be just another beat up, chewed up, dusty, mildewed, sagging outbuilding with a nice weather vane on the cupola. The costs should be allocated to future value, not looks or appearance.

Remember the old addage: "No Roof, No Barn" ?

 

[mddorange]

All the homes in this area have the snap lock metal roofs.

My barn of 100' x 36', ex horse barn, has the normal non-insulated metal roof with screws.

As Newbury stated, it can "rain" a little inside.

The big pain is that over the years the screws have to be replaced to prevent leaks at the screw holes.

 

[EddieWalker]

I'm not familiar with the term "snap lock" for metal roofs, but from looking at the video, it seems like a standing seam roof, which I am familiar with. If that's what it is, then you have no choice, you have to use sheathing to create a deck to attach the metal to. Purlins would be too far apart and I don't believe the metal is strong enough to span anything. What did your supplier say?

The only time you would consider bubble insulation is if you have purlins. The bubble stuff doesn't really provide any significant insulation other then cutting down on condensation that forms on the underside of the metal. The condensation will still form, but it will be less. What comes off of the metal roof will land on the plastic and either flow down to your eaves and into your gutters, or down the sides of your walls. This can cause other issues if not addressed. If you use plastic, but the very best out there because if it falls apart, the only way to fix it is removing the metal roof and doing it all over again.

If you go with R panels, then you can use purlins and space your trusses out a lot farther. How far depends on your trusses. Fewer trusses, purlins instead of sheathing and R panels create a very good roof for the very least amount of money. This is how I did my barn and my shop. When it rains, the metal is loud. If we are uncertain if it's sprinkling or not, we open the door to the shop and we can hear the lights sprinkle hitting the metal.

 

[Milo]

Both Standing Seam (snap lock), and 29-26 gauge G-rib, R-rib, etc. which have exposed surface screws can be installed over 24" purlins or furring strips and will support walking on. I just finished a G-rib metal roof over an old roof (on a 125+ year house on the property I was considering tearing down) that was on purlins. In the interest of saving money and not having the attic open this time of the year we installed furring strips across the old existing metal roof and put the new surface screw panels on that. The installers walked all over it with no denting or issues of any kind and it was just 29 gauge. All standing seam or snap lock metal I've seen is much heavier gauge than what I used, maybe 22 or even heavier. I would also use the type like in the video which incorporates the faint rib bends in the wide panel rather than completely flat.... unless you go with "very" heavy gauge otherwise it'll show ripples.

Standing seam is over double the price of surface screw roofing, maybe triple, and it requires a nice flat surface without bellies or humps. Given you're on new construction I'd definitely choose "snap-lock" for a home or nice new horse barn and I'd probably have OSB under it.