What Is a Rafter?

Rafters are the evenly spaced top members of a pergola that run across the beams to form the open roof and cast the shade pattern.

Rafters are the horizontal boards laid across a pergola’s beams to create the slatted roof. Their size, spacing, and end profile (often a decorative rafter tail) set how much shade the pergola casts and define its style. Secondary slats laid over rafters are called purlins.