A while back I wrote about the insulation plan I have in mind, with sprayed urethane foam on the overheads, under-side of the decks, and hull sides and Mountain Mist Buffalo Batt polyester nonwoven fabric applied with contact cement to the backside of all wooden panels that face the hull and overheads. The spray foam insulation has a lot of excellent properties, including a very high R-value per unit thickness of applied product, it improves structural rigidity (which is always good for cabin tops and aft decks), and it’s self-extinguishing in the event of a fire. I still haven’t decided whether to DIY the spray foam or have a pro do it, but nine rolls of Buffalo Batt arrived and are awaiting fitting and install.
That 1-1/2″ loft should yield an R-value of 3.0, which will be a vast improvement over the original approach that used no insulation on the backside of panels. The R-7 value that each inch the spray foam provides coupled with due care to avoid air leaks between the hull envelope and interior, with a dead air gap between the two types of insulation, should do a good job of keeping the conditioned air on the inside of the boat. In the Mid-Atlantic region, where winter temps recently have dropped below zero Fahrenheit (hello “global warming!”) and summer temps go into the 90s and even over 100°F on occasion, proper insulation is a very important thing. Insulating the back-side of the panels should also greatly contribute to keeping condensation in hanging lockers, drawers, cabinets and storage areas under control.
That’s the theory, anyway, and I’m sticking with it. 🙂