I’ve recently completed a playhouse in the roof area above my front porch: about 160  unconditioned square feet with max head room of 4′.

I elected to use a radiant barrier with about 4 inches of air space separating it from the roof sheathing. I’m sure there are a lot of opinions on radiant barriers on this forum, but it’s up there… Since the rafters are 2×6, this gave me no room to insulate.

The front porch is now under construction and I have open 2×8 bays (the floor to the playhouse). Is it worth putting some insulation under the playhouse floor? Not sure if I’d have humidity problems, but also not sure if it’s worth insulating at all if the roof has zero r value. 

Few other details:

* Access to the playhouse is through the house, but closable through an insulated door

* I live in Kansas City, Missouri. It gets hot here… and cold.

* Wall material in the playhouse is 1x ply shiplap, just something I picked up at a big box store

* Floor material in the playhouse is foam tiles on top of 2×6 subfloor.