Shop Question

knightstead · Apr 22, 2019

I'm having a 40x68 shop/house built and I'm hoping I can get some advice from the experts. I know many pole barn questions have been beat to death but I don't recall seeing too many asking about roof insulation. May main concern is sweating, I'd like to do all I can to avoid that. Shop will be 40x44 and will be stick built with purlins between trusses on 4' centers. I've heard great things about the single bubble insulation but my builder expressed some concerns and I'm not sure if there's another cost effective solution. The lumber yard sales rep said the same thing as builder, bubble insulation will bake and start falling apart in 5-10 years. The house portion of the building will be covered in ZIP Sheathing and I'd not completely opposed to having it put up in the shop, but it is rather expensive and basically has little to no R-value. Does anyone have any advice or experience on what has worked for them? Location is central MO.
Thanks,
Dan

showcrop · Apr 22, 2019

This same question does come up here regularly. The consensus seems to be that spray on foam is the best way to prevent sweating on the underside of your metal roof. You probably know that when it comes to metal roofing that you want standing seam.

knightstead · Apr 22, 2019

Thanks for the response. I guess I should go ahead and get an estimate on the spray foam. I was hoping to go a cheaper route but
I'd sure like to have this done right the first time, might just have to bite the bullet.

coshoo · Apr 22, 2019

Around here (western Washington, the roof sweating capital of the free world), everyone uses rolls of white plastic sheet with about an inch of fiberglass insulation bonded to one side, installed with the insulation on top and plastic sheet on the bottom. It will last forever (unless the building is open to birds, who will tear at it). No sweating, I garr-on-tee. Not sure what it costs, everybody just puts it on. Many pole building guys won't take the job if you don't want it- because they don't want to deal with customer's whining when it's raining inside the building on cold foggy spring and fall days after its built.

Stephen Newell · Apr 22, 2019

Yes, sweating is an issue. My building is insulated however I have six fiberglass skylights and I have to keep a dehumidifier in the building in winter to keep the skylights from raining. I just use the metal building insulation which comes in rolls 5' and 6' wide. It works really well. The building is normally about 20 degrees warmer than it is outside without any heat on. Likewise in summer it stays about 20 degrees cooler.

Bunchgrass Farm · Apr 22, 2019

I have that stuff in my shop roof and I hate it. When you have a leak (and you will unless you're putting in a standing seam metal roof), the water find its way around the screw head and through the roof except that it's trapped up in the insulation where you can't see it ..... until it runs down one of the trusses and shows up "somewhere else". I'm looking at having to pull all my tin off to fix this mess ---- 40x60 shop using 30 something foot pieces of metal roofing. Not fun.

P I Pete · Apr 22, 2019

In my area of the country Wick Buildings uses a steel that has a fuzzy stuff on the underside supposedly does not sweat.

Pete

kcm.MN · Apr 22, 2019

We have a high degree of sweating as well. The only thing that works here is spray foam. An added benefit of spray foam is that it acts as a polyurethane glue, so to speak, and helps to bond everything together. It adds rigidity to a steel roof.

Steve@Advance · Apr 22, 2019

It would be hard to beat the cost and efficiency of the standard white plastic backed fiberglass insulation. It is put down on top of the purlins before the metal goes on.

It will stop condensation.

But, it does not have a real high R value.

For a shop, it would be sufficient, but if there will be a living space or office, a false ceiling with additional insulation will help significantly.

As for the roof material, standard R panel, screwed down with Tek screws, may eventually have some minor leaks. For a shop, you will probably never notice.

But for a living space, or something with drywall, decorative quarters, you would want standing seam roofing. No fasteners penetrate the exposed surfaces.

jCarroll · Apr 22, 2019

I'm in central Ohio.
Have a Lester building that is 6 years old.
Roofing sheets have a fuzzy coating on the underside. Way it works is that condensation is absorbed by the fuzz, and then it evaporates as the building warms. I have never had "rain" inside my barn.

I have seen some really ugly situations where the batt type has ballooned and/or birds have pestered it. Would never use that type.

knightstead · Apr 22, 2019

Thanks again for all the replies. Neither the builder or supply house mentioned sheet metal with the fuzz, so my guess is that's not an option around here. The bird damage is definitely something that I hadn't thought about and I'll take that into consideration. I'll start looking at pricing on the options and see what'll work for the budget and application.

OL88D · Apr 22, 2019

We have a Lester 30 x 100 as our house garage and storage. About 15 years old and have had no problems with moisture.
We put spray foam on walls and used cellulose in the attic/ceiling area.
We have floor heat and have very little problem heating and cooling

jm. · Apr 22, 2019

First off we do not have the extreme tem. swings here in Tennessee so sweating is minimal, but does occur . We have several large pole buildings that has a double sided bubble wrap. That is tinfoil like on each side. Have some that are 12 years old and no change in the insulation at this point. Also no bird problems. I will tell you for sure if you go the spray on route be sure you get it done BEFORE any diesel engine is run in the building. Have a neighbor that built a large one in the summer and was latter in the fall before they sprayed the insulation on. He had a lot of it turn loose and come off.

MarkB_MI · Apr 22, 2019

When it comes to insulation, "good" and "cheap" are mutually exclusive. Listen to your builder's recommendations; he should know what works and doesn't work in your climate.

Mo1032D · Apr 22, 2019

Had a new shed put up after old one burnt. Amish built 40x40. Plastic was put down before concrete floor was poured and had the plastic wrap put on before tin, actually like a bubble insulation wrap. Have had no sweating of any kind with it done that way. Northeast Mo area. Scott

T.C. in Tx · Apr 22, 2019

Here is my experience. I built a shop in 1996 and used the "bubble wrap" stuff with white plastic on one side and reflective aluminum on the other. All was fine for about 10 years and the stuff started coming down. Basically it had just turned to very brittle material and if you touched it, then it would crumble.

Well by now I had a lot of wires, plumbing, you name it up in the ceiling. Bought some 4 inch styrofoam and had had a contractor install that. Made a big difference. Couldn't go with spray foam because of the mess it will make during the install with the particles that fall during application. Would not have been able to cover everything well enough.

Meanwhile, I have a 2,500 foot uninsulated work space attached to the building. It was unbearable in the Texas heat. So, I went with the closed cell spray foam insulation there. The difference is dramatic. I measured the bare tin in mid day at 152 degrees. Right next to it where the insulation had been sprayed on it read 99 degrees--only l degree above ambient temperature.

No doubt in my mind, any future construction gets the spray foam

Northvale PA · Apr 22, 2019

For those considering spray foam, the manufacturer will give a single pass application maximum thickness. If that gets exceeded before it cures for about 20 minutes, it will actually heat up internally, then shrink and pull off the substrate. Read the installation instructions and do NOT assume the installer automatically follows the recommendation. They normally try to speed thru the work with one pass.

Geo-TH,In · Apr 23, 2019

Sweating is common in Indiana. Plastic won't last forever. I built my pole barn with trusses on 2 ft, osb and the best shingles. Back then, the price was the same as a metal roof. I've yet to have an issues with sweating. NO plastic under my 6 inch floor. I do have 1 ft vented eves, ridge vent.

I live in a county that has area planning so, I have to first visit the board of health to see if I can build. Can't build in a flood. I can't build pole barn unless there is a house on property.

Next I have to go to building inspector and get a permit. Many requirements, building codes and electric codes to follow.

Next stop should be at the assessors. Find out what your taxes will be. You may adjust your plans to lower your taxes. Stick built is more than pole barn.

buickanddeere · Apr 23, 2019

First and foremost . The shop is too small . Double the floor area and you will be able to just squeeze everything in that you want to .

Mike M · Apr 23, 2019

For just vapor barrier many in Ohio have a white material made for this application. It has strands running within it to help reinforce it. Seems to hold up well. If you are planning on insulating anyhow then spray foam may be the best route but is real expensive. In Ohio if you put metal roofing up you NEED a vapor barrier under it. I have not seen the steel with fuzzy backing yet ?

GregtheDC · Apr 23, 2019

I live in Sedalia and we are building a new church and using the spray in foam. It has a great R factor, our Job Super says it the first he has worked with and the contractor did a good job and it appears to be a great product.

Bunchgrass Farm · Apr 23, 2019

Standing seam usually requires an installer -no? Or can you rent to seam crimper tool etc? That roof can get pretty pricey when you have it installed by someone else.

Almost every barn/shop builder here uses the standard 29 ga metal and screw it to the purlins ---- and, almost guarantee some half hits and misses when they're flying blind due to the vapor barrier occluding their vision of the 1.5 in wide purlin. Guess that's where we get the leaks, eh?

One tip I was given regarding attaching the tin w/ screws was to stack a pile of similar lengths together (say wall metal), mark the screw positions w/ a punch(every 2 ft if that's purlin spacing) and then predrill the holes (through 8 sheets or so at a time). Shooting the screws goes so much easier when you're not trying to start a hole in the metal with a screw AND it allows you to fine tune the metal positioning because you're not monkeying with the screws so much.

showcrop · Apr 23, 2019

One of the main problems with screw down metal is the expansion contraction opening the holes so that the screws are no longer tight. Another problem is the sun woking on the little O-rings under the screw heads. Most of the screws and holes stay good for a long time but here and there they open up and leak.

knightstead · Apr 24, 2019

Thanks to you guys I think I can say I ruled out the bubble insulation. Just got a quote for 2 inches of the closed cell spray foam that would be R-14. Came in at a little under 4K. That's more than I wanted to spend but I might just go for it.

Shop Question

Member

Well-known Member

Member

Well-known Member

Well-known Member

New User

Member

Well-known Member

Well-known Member

Well-known Member

Member

Member

Well-known Member

Well-known Member

Member

Member

Member

Well-known Member

Well-known Member

Well-known Member

Member

New User

Well-known Member

Member

Similar threads