Roof-Ceiling Construction

Attic Access Is Required When the Attic Is Large Enough to Enter

When is attic access required by IRC 2021?

R807.1

Ceiling Joists Often Serve as the Roof Thrust Tie

Can ceiling joists be used as rafter ties?

R802.3.1

Enclosed Attics Need Code-Compliant Ventilation or an Approved Unvented Design

How much attic ventilation is required by IRC 2021?

R806.2

Rafter Span Tables Control Roof Framing Size and Spacing

How far can roof rafters span under IRC 2021?

R802.4

Rafter Ties and Collar Ties Do Different Jobs

Are collar ties the same as rafter ties under the IRC?

R802.3.1

Ridge Boards Must Be at Least the Depth of the Rafters

What size ridge board is required for common rafters?

R802.3

Roof Framing Openings Need Headers and Trimmers

How do you frame around a skylight or roof opening under the IRC?

R802.9

Roof Sheathing Fasteners Must Follow the IRC Nailing Schedule

What is the code nailing pattern for roof sheathing?

R803.2.3.1

Roof Sheathing Must Match Span Rating, Spacing, and Fastening

What roof sheathing thickness is required by IRC 2021?

R803.2

Unvented Attics Require Specific Air-Impermeable Insulation Details

Can an attic be unvented under IRC 2021?

R806.5