I have a post and beam house built in 1977. There is a 30’x40’ shed roof (not too bad to walk on). A leak has caused a 10’ x 10’ area of damage, on the low side of the roof, with a mold problem in the roof insulation. There is evidence of mold from the inside. The ceiling is tongue and groove pine placed over the beams from the outside, then rigid insulation and plywood were placed on top.. I plan to remove the section damaged from water from the roof side. Clean the mold, replace the insulation and plywood (or osb..whatever is suggested) and replace the old rolled roofing using the same type again, on the entire roof. I researched nail base insulating panels which appear to be a quick and easy way to fill in the opened area. The approx. 5” depth of the panels won’t match up with the existing “on-site-built insulating sandwich” that is on the roof now. A carpenter said the existing insulation is made up of layers of rigid foam topped by plywood, and is considerably deeper than 5”. I haven’t removed the plywood from the roof yet to see what the exact dimensions, materials and building method are. I want to have a good idea what I’m doing before I cut a giant hole in my roof. I have researched mold mitigation and removing the old insulation appears to be the accepted method to eliminate the problem. If I build an insulating sandwich myself, what holds the layers together and what holds the sandwich to the roof. I live in central Vermont at an elevation where winter winds can be fierce.
Annie

Sounds like a DeckHouse to me. The insulation is held in place by the plywood. It comes in different thicknesses and can be stacked.

Pull the fasteners on one sheet of plywood and lift it off. You`ll see the Coldvent system they use and realize it is no that difficult to deal with. It`s like a jigsaw puzzle with side rafters in between to hold the sections of insulation apart. They`re staggered so maybe take a few off. You can tack them back on and tarp a shed dormer if you feel it is out of your league !!

DeckHouse has a web stie. (owned by Acorn)