In article .com,
tillius wrote:
I'm building a storage shed/play house and was wondering about the need
for using Pressure Treated dimensional lumber on the 2nd floor (Play
house area). All of the lumber in this area will be primed and painted
with exterior latex paint, so I don't know if I need to use PT lumber
in this area. The first floor joists, framing and flooring will be PT
since it is in close proximity to the ground, but if I don't have to
use PT on the kids area, I'd prefer not to.

Anyone have experience with this and know if regular KD lumber will be
OK if it's being properly primed and painted?

Questions in return:

Is wooden _house_ siding PT ?

How long does *it* last, just 'primed and painted'?

grin

You use PT for two reasons.
1) 'rot' resistance when in extended contact with moisture.
2) discouraging insect life, and similar critters from taking up
residence _in_ the material.


Another option is do build "like a house" -- concrete "slab on ground",
with, say three tiers of concrete block, and _then_ the framed walls, etc.
Would pretty much eliminate the need for any PT lumber.