Exterior Roof Insulation

Bare foam board one sided sheathing board or double sided which is also reference as structural insulated panels.

Exterior roof insulation.

Because old roofs were often framed with 2x6s there isn t much room for insulation. It makes a lot of sense if the rafter cavities are already insulated and it is most affordable when the roof needs replacement. Inviting exterior air into the center of your roof assembly between two layers of insulation has the effect of making your rigid foam worthless if you go this route you ll have to spend a lot of time conscientiously sealing up the air intake openings and air outlets for each ventilation channel whether at the soffit vents or at the. Because this strategy involves exterior insulation and over roofing it presents the opportunity to establish a robust water control system at the roof.

Adding exterior foam on an old roof is a good idea whenever a reroof is planned it is a once in 50 year opportunity to bring the house up to higher level of energy performance. Single ply roof systems can provide an easy to install seamless roof assembly. The water control for a sloped roof includes a rain shedding cladding e g. Exterior roof insulation retrofit unvented roof covering the roof of an old house with a blanket of insulation makes the house more comfortable and it cuts energy use.

The later is used in new construction as the interior board serves as an inner wall. Rigid foam board is just above the roof deck or an exterior insulation option. Single ply roof insulation.