Flutterby™! : Metal buildings and heat/insulation? 2009-07-28 16:40:50.352597+02

Metal buildings and heat/insulation?

2009-07-28 16:40:50.352597+02 by Dan Lyke 10 comments

Silly question: We have a semi-enclosed awning structure in the back yard. We've started thinking that we could enclose that structure and move the workshop back there, making the garage space clean and getting the sawdust out of the laundry area.

We'll probably have to go for a code variance because the rear setback of the existing structure isn't sufficient and we'd really like to be up against the fence. So we'll just replace the structure as it stands. We've looked at Tuff Shed, yes, they sell a nicer version than the ones that go through the Home Despot, and could get a 12x20 in the $8k range, but we could get an all-metal (galvanized steel) barn/carport like structure of the same size for less than $2k.

Anyone got experience with how hot a structure like this will get in the summer? What sort of insulation concerns we'd need to deal with generally? And what code's like for wiring it (I assume we'd just run everything in conduit)?

I've also got enough concerns with the Tuff Shed that I'm going to price out doing it myself with commercial roof trusses, and think about engineering the thing to carry the loads of a living roof.

#Comment Re: Metal buildings and heat/insulation? made: 2021-10-19 20:52:38.102185+02 by: Dan Lyke

Wow is this a blast from the past... For future reference: We went with the living roof, and at some point, depending on how water conditions continue, I will probably end up taking off the dirt and putting a couple of layers of urethane foam up, in a way that lets the actual roof be unvented. Although *maybe* there'll be a vent layer. But we'll deal with that some time in the future.

#Comment Re: Metal buildings and heat/insulation? made: 2021-10-17 14:12:30.409143+02 by: TheSHAD0W

Typically you'd insulate a steel roof by laying R-10 foil-reinforced insulation over the rafters/purlins before installing the roof, along with other supplemental insulation as needed. I recently had a workshop put up, and the contractor ran steel strap along the bottoms of the purlins and laid in R-30, before covering with the R-10 and the roof.

With concrete block you've got a lot of options. The block itself is a thermal mass and it's a good idea to exploit it where you can. I'd recommend foam board on the outside, with siding over it. You can glue up the foam board and attach the siding through it using concrete screws.

eric, I think there'd need to be additional steel reinforcement for straight cinderblock, but I'm looking around. Meuon, good idea, I'm checking. That'd be very cool.

Hey, is Aerated Concrete Blocks (typically 4' by 4' by 8") available cheap in your area?

Are cinder-blocks not up to code out there? Do they have problems in 'quakes? Just seems to be the easy way to build up the walls.

Yeah, in a perfect world I think I'd build it myself, concrete slab floor (probably reusing most of the slab that's already there, if that works out for drainage and humidity control), fiber cement siding with a full drainage plane air gap over OSB (if I can sell that to Charlene, if not, then 5/8" ply) sheathing (well above code for a residence, let alone a shop), and fiberglass insulated walls with 3/4" drywall interior (just to make sure that there's solid fire protection on both sides of the walls). I'm guessing that materials and equipment rental (the labor would be me...) that comes out to roughly the same price as the Tuff Shed. And the Tuff Shed or a stick-built building will be cheaper to wire, although not $6k cheaper...

To do it myself I'll probably also need to pay an engineer or an architect to sign off on the plans (+$500 or so), but that'll also get me structure enough to do the living roof even if I don't implement that immediately. And I figure a living roof will make it easier to sell a zoning variance for setback to the neighbor whose bedroom window will look out into the top of this structure.

Building it myself I'd also have to pour a foundation (the Tuff Shed sits on galvanized steel floor joists, which also means equipment would need to be rolled up a ramp to get in to it, the metal buildings just bolt to the concrete), which means I need to educate myself on those portions of code. And I'll also have to enlist a few friends or neighbors into helping me raise the walls.

Beer can sheds are hot if the sun will shine directly on it. But I like metal siding over a wooden frame with insulation. 12x20 is a nice size, I'd build it from scratch or pay someone to do it.

Buying stud-length 2x4's..premade trusses, and using a screw-gun or nail-gun, it'll go up quick.

One thing we need to be aware of: A layer of insulation and OSB or plywood will probably deaden sound better than metal, so we'd need to line the structure anyway.

Given your square footage costs - both in the house and in the yard - the difference between $2K and $20K is negligible. And if you can increase your yard square footage with a living room, you'll be ahead.

And if you haven't been to Dan's house - much like mine in Colorado - the lot is so small that measuring in fractions of acres doesn't make sense (my yard is .126 acres).