Super Insulated Roof Design

The kropper house was the first super insulated retrofit in the us.

Super insulated roof design.

Polyisocyanurate insulation above the sheathing and approximately 91 4 in. Blow insulation onto a flat ceiling. A second non load bearing 2 4 stud wall is built on the interior. Reformulate or coat black membranes to make them reflective.

They typically consist of a conventionally framed 2 4 exterior wall sheathed with 1 2 in. Double walls have been built since the early days of super insulated houses. In 1979 steve kropper and the rowell energy group undertook the retrofit of a 1911 triple decker a three family home design nearly identical to the estimated 18 000 triple deckers in the city of boston. To be considered superinsulated a house must have wall and window r values roughly twice as high as those dictated by area building codes.

The amount of roof cavity ventilation is specified by numerous ratios of free vent area to insulated ceiling area ranging from 1 150 to 1 600 depending on which building code is consulted the 1 300 ratio being the most common. Single ply membranes are pre fabricated sheets rolled onto the roof and attached with mechanical fasteners adhered with chemical adhesives or held in place with ballast gravel stones or pavers. Ample vertical space about 22 inches is ideal exists under most roof slopes to achieve r 60 insulation. The vapor and dew point profiles for our climate showed the potential for condensation on the inside face of the exterior sheathing.

Unfaced insulation is simply cut to fit the girt spacings and then impaled onto fast r rigid insulation hangers which prevents the insulation from sagging. How they can be made cool. Control of ice dams moisture accumulation and heat gain can also be facilitated by unvented roof design. Of cellulose insulation in the rafter cavities the roof shown here has an r value of approximately 63.

With three layers of 11 2 in. In general this level will also be the most. Deck for a thick roof rigid foam insulation installed above the roof assembly can create an energy smart roof. Interior wall and roof condensation was also a concern during design of the monument house because of the very thick walls 12 and roof 18.

Highly insulated ceiling or roof. There are three methods for insulating the top side of the building envelope box. However there is one tight spot that needs special attention. Built up roofs consist of a base sheet fabric reinforcement layers and usually a dark protective.

To maintain a continuous air barrier the stego wrap is connected to the zip sheathing on the walls which doubles as the air barrier.