New Shop Insulation ???

[BDaugherty]

I'm building a 50x50x16 red iron steel building to run my diesel repair business out of. I've got the concrete poured and steel structure put up. The next step is to put the metal up, but I need to decide on insulation first. The following are some facts that I think are relevant to the advice I'm asking for:

1: I'm in West GA with basically the same climate/weather as Atlanta.
2: I bought my entire shop used and plan to re-use all the metal on the roof and sides. It's the heavy gauge R-panel in good condition.
3: I will heat with wood in winter.
4: I have trees all the way around for good shade.
5: There won't be any A/C, but I will have a large fan in one end of the shop to pull air through.

I've looked into fiberglass batts, spray foam, and radiant barrier. My PRIMARY concern is controlling the heat in the hot GA summer which lasts most of the year. Secondary to that is that I want to be able to keep enough heat in during the winter to be comfortable enough to work and not just blow through loads of firewood. Also, I'm mainly brainstorming about the roof right now. I've pretty much decided on $0.28 per square foot 3" fiberglass batts for the walls. I figure it's the best bang for the buck and makes for easy additions later on.

For the roof:
I can get foil faced 4" fiberglass for around $0.32 per square foot. My main concern is that even with the foil, it won't reflect enough heat from the sun to keep me cool. I'm also concerned about the potential for roof leaks to damage the insulation.

The aluminum faced bubble wrap radiant barrier is around $0.25 per square foot. It also works GREAT at keeping the sun's heat out. From my research, it does better at keeping the heat out in Summer than the fiberglass. It's also mostly impervious to water damage.

There is a system by which I can install the radiant barrier to the bottom of the 6" Z's under the roof and then use un-faced fiberglass batts on top to get both a high R value for winter and radiant barrier for summer. However, this system has material costs similar to installed spray foam. Both radiant barrier and fiberglass batts must be installed correctly or their effectiveness is greatly reduced.

I can get 1" average thickness spray foam installed for about $1.20 per square foot. Spraying the roof will save a lot of time on install and it will allow me to get the metal up and find any leaks before the insulation goes in. It's also much more "dummy proof" on the install. However, it's costly, birds will eat it, it will make replacing a roof panel a serious pain, and I don't know how well it will do in summer compared to the radiant barrier.

Who has done this before and what would you do differently? I don't have a huge budget, but I don't want to do anything twice. Any suggestions?

 

[Deleted member 995608]

I'll be honest, I'm lost on this subject. However, I will add that anything permanent such as the "spray on" type insulation could come back to haunt you with future repairs or physical changes In the structure. I'd would certainly add in any future provisions before I sprayed anything anywhere.

This sort of reminds me of the loose, shot in type insulation people use in the homes after the structure was built. What a mess! I have that junk in my attic. I had a water lined break that went unnoticed for a few days. The ceiling Sheetrock broke as usual and the insulation went everywhere in the room below. A year later, we're still vacuuming up fibers.

 

[CBari]

I built a house here in Arkansas about 5 years ago and like you was torn on the insulation options. I really liked the spray foam options but it was very new to our area. I ended up traveling and looking a several jobs that had it here is what I learned.

One of the first buildings that I looked at was a rural fire department. It was a red iron like yours and they sprayed it from the floor all the way to the ridge line and back down so it had no air infiltration. It was very cool in the summer when I was there compared to the outside. I asked about the birds as I didn't see any evidence of them. The answer I was given was that since the foam keeps insects out that the birds left it alone since they didn't have a food source. I am not to sure on that. The other thing they showed me was that it was fire retardant. They took a torch and tried to light some and it didn't light.

The next one I looked at was a house that just had the exterior walls and ceilings sprayed and seemed to have below avg utility bills. I asked why they didn't do the roof as several of the others I had looked at had done it that way. Their answer was that the HVAC contractor told them that since they had such a large attic area that he would need to increase his HVAC unit.

I ended up doing the complete envelope and then some at my house and here is what I can positively tell you. You can step out into my attic on a 100 plus degree day here Arkansas humidity and the attic is comfortable. If the AC is set to 70 then the attic is usually 75-78. I also sprayed my porches and they are cooler then just being in the shade. The last thing that sold me on the foam was my utility bills. My home is close to 5000 square feet that is finished living space and my neighbors are all in the 1500-2000 sqft area and my utility bill has always been less by a 1/3 to 1/2 as much as theirs.

I am looking to build a shop also and will be using the foam, I know it high on a house or any building that you are heating and cooling you will eventual recoup that expense through the utility savings but an unconditioned shop it will be harder to justify that cost.

 

[Wertles]

I'm going through the same debate right now with my new shop. Conventional insulation is about $2500. Spray foam, $9000. If I were working in this shop daily with heat and insulation, the spray foam would eventually pay for itself and would be my number 1 choice. Since I am heating with free wood and only expect to light a fire on average 2X's a week, I can afford to throw an extra log or two on the fire each hour.

As far as the birds liking it, from the two places I called about foam stated there is absolutely no nutritional value in the foam and neither insects nor birds really care for it.

 

[fest3er]

... As far as the birds liking it, from the two places I called about foam stated there is absolutely no nutritional value in the foam and neither insects nor birds really care for it.

Birds don't eat it. They build warm nests with it.