Insulating my model train shed
I recently purchased a 12×16 Handi-house shed and moved it under my long carport here in northern Florida. I plan on dedicating this shed to a nice big model train layout,…around-the-wall shelf type layout with a peninsula portion in the middle.
The shed is built with 2×4 studs on 24″ centers with thin metal siding and roof panels attached to the outer edges of the 2×4 framing. At first I was not going to insulate it, but I have changed my mind. Temp and humidly changes can significantly affect the quality of the track work over the various seasons. So I have added a ceiling fan, and intend to add an exhaust fan at one end of the upper roof area. I will also be adding a small ac unit.
I have been thinking of using foam-board insulation cut to fit in between the 2×4 framing. There is also some 1×3 boards located horizontally around the shed and in the rooftop. This 3/4″ thick board will keep the foamboard away from the external metal skin by 3/4″ (nice airspace?).
Today I was talking with an insulation installer down the road from me and he ask if I was going to put up sheet rock on the inside of my shed. I said no I did not intend to do that. He then gave me a stern warning about the fire hazard that could exist with foam board.. He even suggested that I might consider this bubble barrier insulation such as Reflectix. While I was looking that product up i ran across some postings on this site here that was not very complimentry of that type of product.
So I’m looking for advice of what insulation I should consider??
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Replies
Brian,
Rigid foam insulation is fine. The best way to install the rigid foam insulation is as a continuous layer, not cut up into strips. Fasten the rigid foam to the interior side of the 2x4s, and tape the seams between the sheets of rigid foam. Foil-faced polyisocyanurate is the easiest type of rigid foam to tape.
Don't use bubble wrap.
Your contractor friend is right: Building codes require rigid foam to be protected on the interior side with 1/2-inch drywall for fire safety.
1), Is there any of the foamboard insulation products that are superior to the others in terms of fire resistance?
2) Most of these foamboards have a reflective foil on at least one side. What side should face the interior of the shed? ,...or the 3/4" air space between this foamboard and the metal outer skin??
The problem i have with attaching whole sheets of foamboard onto the inside edges of the 2x4's is two fold,...a) by the time I add this foamboard thickness plus some sort of drywall thickness I end up losing even more space on the inside of the shed (I'm looking to maintain as much 'usable width' so my radius turns of track do not get too small,....b) I wanted to maintain as much access to the 2x4 studding so I could attach a lot of my shelf supports to them. If I put the foamboard on the inside edges of the studs I no longer have a 'compression proof' surface to mount shelf brackets.
I'm not so much the purest that I feel the need to butt the edges of the insulation foamboard up against one-another. I believe if I cut the foamboard into 22.5" strips and wedge it in between the 2x4 studs, I will achieve a pretty good insulation quality,...and it would have a 3/4" air space between the foamboard and the metal skin.
On the inside I might consider attaching sheets of masonite or similar 'tempered hardboard' that could also serve as a base for a painted backdrop.This would then also provide an air space on the other side of the foamboard insulation installed between the 2x4 studs?
Brian
Brian,
Thermax brand polyiso has passed certain fire safety tests, but it still would not be allowed to be installed in a living space unless it was protected by drywall. (Thermax can be exposed where an ignition barrier would normally be installed, but it cannot be exposed where a so-called "thermal barrier" -- a more stringent barrier -- is required.)
You can abandon your idea of using rigid foam if you want, and just install mineral wool.
Masonite probably won't be accepted as a thermal barrier -- you need 1/2-inch gypsum drywall.
If you go ahead with your plan of installing 22 1/2-inch-wide strips of rigid foam, you may want to read this article: Cut-and-Cobble Insulation.
"You could install ECOCELL between the studs and leave it exposed".
I almost missed your posting there as it was rather brief.
That looks like a REAL INTERESTING solution!. I must do more reading, and get some idea as to availability to me in FL and pricing.
Brian.
You could install ECOCELL between the studs and leave it exposed.
I don't know, perhaps your building is "Group U" and can have certain types of exposed DOW rigid foam insulation.
http://www.greatlakeshomeperformance.com/wp-content/uploads/2015/02/ICC-ES-Styrofoam-ESR-2142-Code-Report.pdf
So far I am very interested in that ECOCELL product, and it appears to have a good enough insulating factor that it would not require a foil on one face,...is that true?
Anybody have personal experience with this product? Anyone know of pricing per sheet? I have filled out there form, and await info from them.
Brian
Brian,
You may be overthinking this. Almost any insulation can go between the studs -- fiberglass batts are the cheapest option and are widely available. I doubt if there are many code restrictions on this type of building, so the details are up to you. Cover the fiberglass batts with plywood, OSB, or masonite, and you're all set.