Installing a New Roof Over Existing Roof
I am renovating an older house, and recently found out there are high levels of lead paint on the existing standing seam roof. I had originally planned to replace the roof, but now that we have a 2 month old baby in the house, I want to do as little disturbance as possible. The new plan is to encapsulate the existing roof with an encapsulating paint, and then use 2×4 and 1×3 strapping to form a base for a new metal roof on top of that. I would run the 2x4s flat, parallel with the seams, and then 1×3 strapping or purlins perpendicular to have a base for attaching new roofing. I guess I could use plywood instead of purlins, too. The attic space is uninsulated, and I had hoped to insulate it from above after taking the old roof off, but i’m not going there anymore. wanted to do that so we could leave the ceiling open inside. Im thinking my options now keep the ceiling, and install gable vents on either side. Is there a way to install exterior insulation with the new roof on top? we will have an 1-1/2″ air gap between the two roof layers – will that cause any issues ? how would one approach insulating something like this? possible to spray cellulose ontop of the drywall ceiling, but would be difficult to keep it from touching the rafters as it is only a 3:12 pitch. perhaps the new air gap will make it so that doesnt matter?
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