Deck Inspection – Beams/Joists

The beams and joists form the fundamental structure of the deck platform. They must be correctly sized, arranged, and connected to perform properly.

Table 3A sets the requirements for how a dimensional lumber beam must be constructed based on the desired length of the beam vs. the span of the joists being supported.

BEAMS JOISTS TABLE Dimen Beam Span

Table 3B provides the same information as Table 3A for Glue-Laminated beams.

BEAMS JOISTS TABLE Glue-Lam Beam Span

The maximum allowable span or overhang for a joist is determined per Table 2, and is based on the joist spacing, lumber size, and wood species.

BEAM JOISTS TABLE Joist Spans and Overhangs

Beams built up from dimensional lumber must follow certain protocols. Figure 4 provides the guidelines.

BEAMS JOISTS FIGURE Beam Assembly

Joists and beams must be securely connected to prevent uplift and lateral displacement. Joists must be properly supported.

BEAMS JOISTS FIGURE Joist to Beam and Joist Hangers

DCA6 requires specific rim joist details.

BEAMS JOISTS FIGURE Rim Joist