Review Foam Roof Exterior Insulation

But despite the fact that it has been around for 50 years some members of the public have strong negative impressions of it.

Review foam roof exterior insulation.

These 2x4s are extended at the eaves and rakes to create a roof overhang. It typically has 3 variations. Spray foam insulation is a great product. Today we discuss one of the highest performing and most affordable roof systems in commercial roofing spray polyurethane foam.

In climate zones 6 7 and 8 you can have either r 30 in the wall cavity or a combination of r 20 cavity insulation with r 5 exterior insulation r 20 5 or a combination of r 13 cavity. When combining exterior foam insulation with fiberglass cellulose or mineral wool roof insulation the foam layer must be thick enough to keep the sheathing temperature above the dew point. If you are planning to install metal roofing then you would install asphalt felt above the rigid foam followed by 1x4 or 2x4 purlins 24 inches on center then the metal roofing. Their drawing does not show the use of exterior foam on the roof though a.

Bare foam board one sided sheathing board or double sided which is also reference as structural insulated panels. Then 2x4s usually installed on the flat are installed above the rigid foam. Rigid foam board is just above the roof deck or an exterior insulation option. The most common problems that occur around the use of icynene is the belief that it can have a negative effect on the roof of the loft.

However 100mm of spray foam insulation is equivalent to around 170mm of loft insulation according to the national insulation association. All three types of rigid foam insulation expanded polystyrene eps extruded polystyrene xps and polyisocyanurate are suitable for use on the exterior of walls and roofs though they do not perform equally. The easiest way to insulate your roof is with one or two layers of rigid foam insulation installed above the roofing. Eps is the most vapor permeable of the three types.

Homes insulated with it can be some of the most efficient and comfortable homes built. For building owners who seek reliable lasting roof protection that offers long term cost effectiveness spray polyurethane foam roofing offers a great solution. The persist approach shown in that article includes rigid foam above the roof sheathing. The later is used in new construction as the interior board serves as an inner wall.

At r 4 it also has the lowest r value per inch. Causing the timbers to rot. Otherwise water vapor can condense on the back side of the sheathing elevating the moisture content of the materials and possibly resulting in mold and rot.