Log store glossary: capacity, treatment and storage terms

Bay

A separately restrained section of a store. Bays make rotation easier and support the ends of a wide stack.

Bearer

A horizontal member beneath a floor or stack. It raises the load, spreads weight to supports and allows clearance below.

Clear internal dimensions

The unobstructed space available inside posts, rails, shelves and roof structure. Use these for capacity; use external dimensions for site fit.

Cross-flow

Air movement through one face and out through another. A single open front helps, but open ends or a rear gap improve the route.

Loose volume

The volume occupied when logs are tipped or poured into a container, including large random gaps.

Pent roof

A roof with one continuous slope.

Stacked volume

The rectangular volume occupied by logs arranged in rows, including ordinary small gaps between pieces.

Use Class

A classification connecting timber treatment or durability requirements to the conditions in which the timber will serve. For example, current industry guidance describes uncoated exterior timber above ground as Use Class 3 and ground-contact timber as Use Class 4.

Usable capacity

The volume that can be filled safely while preserving roof clearance and access. It excludes framing, shelves and awkward roof voids.

Sources

• Wood Protection Association buyer's guide — terminology checked 10 November 2026.