All About DIY Spray Foam Insulation Kits ~ Closed-cell polyurethane spray foam has some pretty awesome qualities. It has a high R-value. It’s resistant to water, mold and insects. It expands into hard-to-reach nooks and crannies. Heck, it can even add structural support to walls and roofs.
Insulating Cathedral Ceilings: When Tom insulates a cathedral ceiling or a finished attic, he also turns to foam. Sprayed against the underside of the roof deck, it seals against air movement, eliminating the need for a vapor barrier or ventilation. But its open-cell structure still allows moisture to escape.
Prefer spray-on type insulation. Polyurethane foam works best in combination with ceramic insulation paint. The paint is obvious for the exterior of the shipping container, while the foam is for the interior. The paint contains a special gas that contains inside bubbles, which gives it a high thermal efficiency. The spray-on foam is available in both “open-cell” and “closed-cell”. The difference is in the price tag, density, strength, R-factor and in waterproofing.