[jyl]

Elevator - ha. There is a pulley operated basket from ground to the deck, but no-one uses it. When I first built the treehouse he was only 7 y/o and needed both hands to climb the ladder. Now he simply walks up the rungs no-handed.

I was at one time going to install an intercom to the house, but now he has an iPhone which he brings up there so no need.

Looking at Hugh's post above, he mentioned a risk of mold if I panel with 1/4" ply. I assume the problem is that plywood doesn't breathe? Suppose I drill small vent holes in the ply, at the top and bottom of each space between the studs?