Roofing Assembly Layers

Roofing requirements for the design materials construction and quality of roof assemblies for residences are listed in the california residential code chapter 9.

Roofing assembly layers.

You can usually see the underside of plywood decking from the attic. The roof deck is the roof layer also called sheathing that is installed between the trusses joists and underlayment layer in a typical roof install. The roof decking acts as a unifying structure by tying the trusses joists together. The sy stem consists of a roof cover ing and roof deck or a single component serving as both the roof cov ering and the roof deck.

We ll lay out these important pieces of the roofing puzzle and break down each one so you can fully understand the importance of each layer. A roof assembly includes the roof deck vapor retarder substrate or thermal barrier insulation vapor retarder and roof covering. Base layer attached with 1 7 8 48 mm 6d cement coated nails 6 152 mm o c. Built up roofing bur systems popular in north america for more than 100 years built up roofing bur systems are composed of alternating layers of bitumen asphalt and fabrics called roofing felts.

The covering applied to the. A roof assembly includestheroofdeck vaporretarder substrateorthermalbar rier insulation vapor retarder and roof covering. All materials used in a roof assembly must be both weather and fire safe as well as compatible with each other. And nails for base layer spaced 6 152 mm o c.

The felts are reinforced with either glass fiber mats or organic mats ply sheets and when joined with the bitumen form a durable roofing membrane. Bur is preferred for low slope or flat roofs because it creates a continuous sealed surface. Decking most often made out of plywood this roof layer is installed over the framing in a typical roof install. Here are the layers of a roof in order of application bottom to top.

Built up roofing also called bur is the most common roofing material used on low slope roofs. Where the existing roof assembly includes an ice barrier membrane that is adhered to the roof deck the existing ice barrier membrane shall be permitted to remain in place and covered with an additional layer of ice barrier membrane in accordance with section r905. The system consists of aroof covering and roof deck or asingle component serving as both the roof covering and the roof deck. A system designed to provide weather protection and resistance to design loads.

Sound tested with studs 16 406 mm o c. Roofing layers from the framing to the shingles so we ll start at the bottom of the deck and work our way up through all the roofing layers until we reach the shingles and sunshine above your roof. It is composed of alternating layers of reinforcing fabric and bitumen asphalt and is finished with a top layer of aggregate such as stone or gravel. Framing includes the roof trusses that sit at the top of your house and support the weight of all the materials used to build your roof.