Insulation Below Roof Deck

I would use polyiso with a top layer of eps as recommended in your blog post on the topic.

Insulation below roof deck. This variation on the unvented attic design requires a thermal barrier such as an approved intumescent coating. How to attach rigid insulation on the underside of the roof deck. 07 22 00 roof and deck insulation. Below you will find links to company and product information for manufacturers and suppliers listed in the roof and deck insulation section of sweets.

Placing a layer of fluffy insulation below the roof deck would needlessly complicate the. The ratio of insulation above the roof deck or air permeable insulation below the roof deck is a matter of climate and interior conditions. Hence the term cold decks construction materials wood based products absorb moisture. The project is in climate zone 4 seattle area and i want to have an open beam look in the ceiling.

This section outlines the conditions for unvented attic roof assemblies. I m considering a roof design that would place all the insulation above the roof deck with no insulation below. Insulation above the roof deck or air vapor impermeable insulation below the roof deck is needed for condensation control in an unvented roof. The roof deck is cold wood decks without insulation above them will readily equilibrate to the exterior temperature.

Note that table r806 5 indicates the amount of insulation above the roof deck or air impermeable insulation below the roof deck required for condensation control assuming minimum required total insulation as indicated in section n1102 building thermal envelope. With rising heating and cooling.