Mansard Roof Insulation

I recently purchased a home with a mansard roof i had some roofers come to give quotes to replace the top it is finished and they all recommend adding ventilation known issue with mansard s.

Mansard roof insulation.

Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation. To insulate the roof you will need to use a combination of insulation to fully protect the roof. The steep roof with windows creates an additional floor of habitable space a garret and reduces the overall height of the roof for a given number of. Lap the roof underlay over the mansard underlay by minmum 150mm.

Mansard roof with mansard tiles ensure that a clear ventilation path is maintained from eaves to ridge where insulation is positioned between the rafters. Establish the correct number of courses of mansard tiles to maintain minimum headlap of 65mm. Originally i was toying with the idea of closed cell spray foam for the whole mansard floor but i do not want to tear down historic plaster. After having dense pack installed in the building walls the mansard is the next target.

I have a house with mansard roof in boston. One strategy would be to incorporate the attic into the conditioned space and then use a sandwich of barriers and insulation under a furred vented. So now i m thinking about just insulating the little attic which is formed by the low sloped part of the. A mansard or mansard roof also called a french roof or curb roof is a four sided gambrel style hip roof characterized by two slopes on each of its sides with the lower slope punctured by dormer windows at a steeper angle than the upper.

With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same.