Got all of the chipboard and siding on the other walls, too hot to do much more! The walls of the base structure are complete, chipboard with plywood siding over it. The hatch still needs to be built up but since I need easy access to the inside that’s last. Today I’ll strip down the roof and make sure it’s perfectly square to the structure by screwing the baseplate to the structure while I reassemble the roof. Once that’s done I’ll put chipboard and siding on the sides of the roof and head off to Home Depot for some steel roofing material. Silver is probably best to minimize heat although from a security standpoint once it’s out at the dark sky site a darker color would be better since I don’t want to advertise the existence of the building by having a shiny roof! For the time being tho a light color would be best to provide as much heat rejection as possible.