IraRat wrote:Dale, I just went one panel of 3/4" insulation all around. Floor, sides and roof.
The Cubby plans only call for 3/4" for the floor and sides--because structurally, you don't need to frame the walls with sticks any bigger than 3/4" deep. The Cubby sides are fairly thin (don't remember, 3/8?), but if it's 3/4" for this, you certainly don't need thicker framing if you're using a thicker ply side.
But they also tell you to use TWO panels of this insulation thickness for the roof, for a 1 1/2" total thickness, because that's your spar depth/thickness/width.
BUT AGAIN...
I am 100% NOT concerned with insulating for any cold down here. (I insulated for the body moisture/mildew factor ONLY.) I guess because heat rises, the Kuffel plans call for doubling up the roof insulation to keep heat from escaping, to help you in cold weaher. And since you have that 1 1/2" to work with, thermodynamically speaking (who, me?), you're supposed to fill it completely to eliminate voids between the exterior and interior roof skins.
But when it comes to our hot weather here, and my 5200 btu air conditioner, I really don't think you don't need ANY insulation to keep that thing DAMN cool.
I'm only doing 3/4" thick spars in the ceiling, except where the fan goes and the roof will thicknes will taper into 1 1/2" into it and back out again. The rear will be thicker to have heavier framing to both support my A/C and provide for depth for outlet boxes. Front, most of the top, and sides will have 3/4" insulation. I agree with you on insulation for Florida. And, yes, even with my larger trailer, the 5200 BTUs will be OVERKILL for cooling. OK...one layer of 3/4" underneath too should suffice with the 3/4" wood floor with vinly flooring or possibly in/out carpeting.