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Roof question on a shop build

Joined
Jan 16, 2017
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Eastern Washington
I'm looking at having a post frame/pole building built this year to be used as a new shop. I've been in talks with a contractor and had asked about upgrading the roof metal to 26g ($1250 upgrade). The contractor said that in our area the standard 29g would be just fine. We don't get hail but we do get some high gusts of wind once in a while.

I'm curious if going 29g is okay or if I'm better going a hair over budget and sticking with the 26g. For those that have done shop builds what did you do and would you do it differently if you had to do it again.
 
Joined
Oct 23, 2015
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Location
Springdale, Arkansas
I've had 3 metal roof buildings with 29 gauge roof panels. The oldest is 25 years old. None have had a problem.

I live on a large lake. The dock builders mostly use 26 gauge for the added strength. There and commercial buildings is about the only place I see it used.
 
Joined
Apr 20, 2006
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Erie, PA
My shop is connected to my house. 10 foot ceilings, R19 in walls, R38 in ceiling metal roof etc. The only thing I would do different is make it at least 16 feet longer.:D
 
Joined
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Smithville, MO
You might find out what spacing your contractor puts his purlins on.( the ribs that the steel is screwed to) You could always have the purlins spaced closer to increase the number of screws that is used to attach the metal. That would be way cheaper than going to 26g. Be sure they use screws and not ring shank nails. The screws won't work loose with he movements of wind.
 
Joined
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Eastern Washington
Thank you guys for your feedback. The purlins are 24" on center. I had an opportunity to talk to a few neighbors and they all have 29g metal on their roofs so I'm going to follow the builder's recommendation and not get the upgraded 26g.

The building we're discussing is 24x24 with a 10' wall height, 4:1 roof pitch, concrete slab with 2" insulation underneath. There will be a six foot covered patio off one end and a 4' lean to along one side (covered wood storage). R19 in the walls and R38 blown in above the ceiling liner. Hope we get this worked out and that it actually gets built.
 
Joined
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Ponsford, MN
The heaver GA might be an advantage if you get a heavy snow load in which case a steeper pitch and wafer board instead of purlins would be a better solution.
 
Joined
Aug 14, 2007
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Eugene, OR
I had a 24 by 36 pole barn type shop for about 15 years. Yes, you need insulation on the roof. I also put plywood up on the ceiling rather than leave the rafters open. There was a little storage area down the center. An added benefit to covering the ceiling was that it provided support for my DC duct work. Oh, I found out that the neoprene washers on the screws are good for about 15 years and then they need to be replaced. I had a few leaks and talked to a roofing company who told me about how those seals wear out. Had them all replaced. Depending on how many trees you have near the shop, you might want to consider one of those leaf guard things for the gutters. Mine filled up and the over flow was leaking into the building. I don't care to go up on roofs any more....

robo hippy
 
Joined
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The first building I put up on my retirement property in 2004 is a 24' x 24' storage building stick built but with purlins on the walls and roof. The purlins are 3/4" thick and a few years back I started getting leaks so I had someone go up on the roof and he tightened the screws and that seamed to take care of the problem.
The 30' x 40' shop was put up in 2008 and that is also stick built but with wafer board sheathing on the outside walls and roof. The siding, roofing and ceiling sheathed with Steel and the inside walls are sheathed with wafer board. The ceiling has blown in insulation and the 2 x 6 walls have batt insulation. At this point I have not seen any indication of leakage, so it would be a good idea to have someone go up there and check the screws.
 
Joined
Jan 16, 2017
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Eastern Washington
I had a good conversation with the builder today. He told me that when he does roofs he sheets it, lays synthetic felt then puts the roofing metal on. I did tell him not to do the 26 gauge upgrade. If this works out for the both of us and I let him build then he'll put 2" foam boards under the concrete, I forgot to ask about a moisture barrier under the foam but will mention that when its time (probably one of a few add ons). He is having to redo the bid right now, he didn't see my note about wanting a ceiling so he is having to change the trusses to bottom load trusses, and he'll install the joists and osb ceiling. I have no idea what that will do to the bottom line, hope it stays within budget.

Here is a mock up of what I have asked for. The only difference is these pictures show a 12' wall height where my buidling will be 10'. The lean to is 4' deep for wood storage and the patio is 4' deep as well, a place to sit and enjoy the view over the valley. Anyway, its in the planning stages so its still a dream, if I'm lucky we'll get the numbers right and make it happen.

Here in Spokane its difficult to find a post frame building willing to do anything smaller than 30x40 or 50x60. Most are booked until November, only want large jobs and will only do a shell so they can move onto the next job. This builder is willing to do extras like insulate, ceiling and attic ventilation. Oh, and he's willing to do a smaller shop though I suspect I'm paying dearly for it. Anyway, here is what I am dreaming of.
The shop - east side.png The shop - west side.png The shop -north side.png The shop -south sdie.png The shop alternate view.png
 
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Nice design especially the over hang all around and the entry's on the gable ends, but if it were me I would eliminate that shed roof on the north gable end.
 
Joined
Jan 24, 2010
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Cleveland, Tennessee
Interesting thread. I put the leaf screens on my gutters when I first moved in. They caught leaves, got wet and pulled the gutters from the house. Tossed them.There is a company that makes a baffled system (looks like a mini blind) that turns the flow off the roof into a gentle rain. Can't remember the name.
 
Joined
Aug 14, 2007
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Eugene, OR
The gutter protection I used is called Leaf Filter. Ran into them at a local home and garden show. Life time warranty, so they should last longer than me. Small enough screen so that nothing smaller than saw dust can get in.

As for the vapor barrier under the slab, it is only required for 'living spaces'. You don't get as much rain over there in Spokane as we do here in Eugene. Biggest difference it would make is that if you want to adhere some thing to the slab, like linoleum, then the glues may not stick. If you want to put down laminate flooring, it might help, though some of them are water proof now, using ground lime stone as the base. So, in the shop, not necessary. The insulation under the slab will definitely keep it warmer in the winter. You can install thinner stuff on the sides of the slab as well, then vapor barrier over that. If you want a cheaper version of a vapor barrier, a couple layers of the more heavy duty black plastic will do a pretty good job, though compacting gravel on top of it will put holes in the plastic. I never did like it on top of the gravel and then pouring concrete directly on the plastic. Concrete would harden from the bottom up, so the top was still sloppy wet while the under parts were rock hard. Made it more difficult to get a good surface without a troweling machine. I did residential concrete for years.... Glad I don't do it anymore....

robo hippy
 
Joined
Jul 10, 2017
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Windermere, British Columbia
The gutter protection I used is called Leaf Filter. Ran into them at a local home and garden show. Life time warranty, so they should last longer than me. Small enough screen so that nothing smaller than saw dust can get in.

As for the vapor barrier under the slab, it is only required for 'living spaces'. You don't get as much rain over there in Spokane as we do here in Eugene. Biggest difference it would make is that if you want to adhere some thing to the slab, like linoleum, then the glues may not stick. If you want to put down laminate flooring, it might help, though some of them are water proof now, using ground lime stone as the base. So, in the shop, not necessary. The insulation under the slab will definitely keep it warmer in the winter. You can install thinner stuff on the sides of the slab as well, then vapor barrier over that. If you want a cheaper version of a vapor barrier, a couple layers of the more heavy duty black plastic will do a pretty good job, though compacting gravel on top of it will put holes in the plastic. I never did like it on top of the gravel and then pouring concrete directly on the plastic. Concrete would harden from the bottom up, so the top was still sloppy wet while the under parts were rock hard. Made it more difficult to get a good surface without a troweling machine. I did residential concrete for years.... Glad I don't do it anymore....

robo hippy
I always use vapour barrier under slab . Stops excessive moisture loss from concrete while curing for one thing. Stronger slab.
 
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