Willamina - "no where fina..."
Haha. I mean when you look at the cost performance...We could literally put a a new tarp (or three) over the thing every year from November until May. It's not like we have to worry about curb appeal.
Construction Experts - Polebarn Roof Condensation and Leaks
- Thread starter chuffer
- Start date
Willamina - "no where fina..."
My buddy is a commercial contractor and he put a new roof on an existing roof recently. It was quick and dirty but effective. They laid wood down on the existing roof on a grid, screwing through the roof and into the joists. They screwed the new roof into the wood grid they had just laid down. It got the job done!
Hopefully your trusses aren't rotting out!
Hopefully your trusses aren't rotting out!
The roof on a roof appeals to the side of me that says “just fix it good enough and get on to the important stuff.” The arguably more sensible side says “fix it right the first time…”
The nihilist in me says “don’t do anything, bc it doesn’t matter.”
The nihilist in me says “don’t do anything, bc it doesn’t matter.”
IMO if you have purlins and are using barn siding you dont need sheathing. Now it would really help your condensation problem if you had 2" poly iso foam between the barn siding and the purlins and taped the seams on the foam. If you really really want to not leak after that then you could put ice and water shield on the poly iso, that would mainly just make sure the condensation on the back of the roofing or any seam leakage can just run down and out of the air gap from the high points in the corrugation. Then you can insulate on the inside with your choice of insulation, spray, fiberglass, rock wool, whatever.
Interesting. What kind of fasteners get used for in that case? They have to be pretty long to get through the 2” foam and into the purlins, no? Also, wouldn’t the fasteners see a lot of shear stress in this type of usage?
GRK RSS and Simpson SDWS are both structural screws used for that application. I'm sure there are others, but both of those are widely available at your big box store.
Insulating outside of the sheathing envelope (whatever that happens to be) is commonplace these days with higher efficiency residential buildings.
EDIT: misunderstood your question. Disregard the above.
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the purlins are going to take the shear that’s the point. The barn siding really isn’t meant for shear loads, which is why you’re allowed to use screws to attach it instead of nails. And the roof fasteners main loading is going to be tension from wind wanting to pull it off, then some shear from the snow load, but the lower your pitch the less that load is. You’re going to need to probably add the gaskets washers to whatever screw you go with since I’ve never seen them that long with gasket washers, definitely something 3.5” long though.
Bold above is what I was asking about. Will the foam insulation provide enougj crush resistance to create enough tension load in the screws.
I kinda like the idea, but like you said…3.5” self tappers with the the gasket washer…not sure if they exist.
Fyi, you guys rock!
#12 X 3-3/4" InsulDrill Metal Roofing Screw - Black, Pkg 100
The Sealtite InsulDrill screw is a self drilling, hex washer head metal roofing screw that provides several features to strengthen the metal to wood bond in roofing. With a #1 drill point, the InsulDrill screw can penetrate 18 gauge steel without pre-drilling and the thread is designed to have...
www.fastenersplus.com
They go all the way up to 8"!
Does your giant bong shed have a ceiling? From reading it sounds like just open rafters? If not install a ceiling, blow 2’ of insulation in that bitch. Leak gone, because if you can’t see the leak, it’s definitely not there. I’m a problem solver.
