Insulation questions

[jgorm]

I'm trying to find the cheapest way to add adequate insulation to the stick built office inside my steel building. The building itself is not insulated. The walls are 2x6 and are built at the end of the girts. This yields 14" of space. The joists are 2x12s. I'm not sure if I should hire it out, or do it myself. I've heard that you can hire for the same price that the insulation costs at the depot. I was thinking about rolling some bats behind all the wood studs, then using paper faced (R20?) for 2x6s.

Originally I thought that polyurethane would be ideal, but it cost ~$1 / board foot! That ends up being ~$150 per stud width!

I'd like to insulate it just in case I have someone stay the night in there during the winter, and keep is cooler in the summer. I'm in San Diego and the coldest it ever gets is the high 20s, but that is only a couple days a year. The office area sits on probably 10+ yd of concrete with a 3x3x6' footer in the corner, 24"+ wide by 4' deep footers on the outside walls, and normal 12x12 footers on the inside walls. (the concrete guys just kept digging!) I'm hoping that all that mass will keep it cool in the summertime where the temps can reach 100 for a few days a year. I've also thought about the blow in insulation, but I don't know how that works with new construction, or if it even works in walls. Here are some pictures.

 

[pattenp]

I'd just do it myself using batt insulation. That's not much to do to hire someone.

 

[theoldwizard1]

Batts or roll is the easiest, but not necessarily the cheapest.

You should have put exterior sheathing along the walls that face the steel outside skin. Then you could cover the inside with scrim and you could used blown in cellulose. This is usually the cheapest.

You can use lose cellulose on top of the ceiling be simply building up the outside edge of the room using plywood and then blowing cellulose on top.

 

[St-rider]

That's a prime candidate for kraft faced rolls, not batts. A mini-split hvac unit would be a great way to heat and cool when needed.
By all means get a insulation quote to compare

 

[CNGsaves]

In San Diego . . . . . heck a light jacket and pillow should be all you need !!!