Insulation Below Roof Deck

The project is in climate zone 4 seattle area and i want to have an open beam look in the ceiling.

Insulation below roof deck.

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

The greater your home s thermal resistance factor or r value the more energy efficient it is. Insulation above the roof deck or air vapor impermeable insulation below the roof deck is needed for condensation control in an unvented roof. Hence the term cold decks construction materials wood based products absorb moisture. During cooler night times and in winter periods the deck temperature can then be below the dew point of the interior air.

Placing a layer of fluffy insulation below the roof deck would needlessly complicate the. Gaining in popularity is the design approach of insulating on the underside of the roof deck and leaving the spray foam exposed to the occupants below. The roof deck is cold wood decks without insulation above them will readily equilibrate to the exterior temperature. With rising heating and cooling.

How to attach rigid insulation on the underside of the roof deck. 07 22 00 roof and deck insulation.