Insulation Below Roof Deck

I m considering a roof design that would place all the insulation above the roof deck with no insulation below.

Insulation below roof deck.

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. This variation on the unvented attic design requires a thermal barrier such as an approved intumescent coating. The roof deck is cold wood decks without insulation above them will readily equilibrate to the exterior temperature. Below you will find links to company and product information for manufacturers and suppliers listed in the roof and deck insulation section of sweets.

The project is in climate zone 4 seattle area and i want to have an open beam look in the ceiling. During cooler night times and in winter periods the deck temperature can then be below the dew point of the interior air. The ratio of insulation above the roof deck or air permeable insulation below the roof deck is a matter of climate and interior conditions. How to attach rigid insulation on the underside of the roof deck.

Placing a layer of fluffy insulation below the roof deck would needlessly complicate the. This section outlines the conditions for unvented attic roof assemblies. I would use polyiso with a top layer of eps as recommended in your blog post on the topic. With rising heating and cooling.

07 22 00 roof and deck insulation. The greater your home s thermal resistance factor or r value the more energy efficient it is.