How much does Western Hemlock move?
Western Hemlock has moderate seasonal movement, typical of many furniture woods. Standard wood-movement precautions on wide panels apply.
A 24-inch-wide Western Hemlock panel, across the seasons
Going from humid (summer, unconditioned) (about 13% moisture content) to dry (heated interior, winter) (about 6%), a 24-inch-wide Western Hemlock panel changes width by roughly:
0.49″
Flatsawn (plain-sawn)
Tangential shrinkage 7.8%
0.26″
Quartersawn
Radial shrinkage 4.2%
Computed with the USDA Forest Products Laboratory dimensional-change formula from published green-to-oven-dry shrinkage figures. Real-world movement varies with your actual humidity range, board width, and how the wood was dried, this is a representative estimate, not a guarantee.
Flatsawn vs. quartersawn Western Hemlock
Flatsawn Western Hemlock moves about 1.9× as much as quartersawn across its width (tangential shrinkage of 7.8% versus radial 4.2%). That’s why quartersawn stock is prized for tabletops, wide panels, and anything where seasonal movement would cause problems, it moves less and stays flatter. The gap is modest for Western Hemlock, so flatsawn stock is often perfectly workable.
Run your own numbers
These figures use a 24-inch panel and a typical seasonal swing. For your exact board width and humidity range, use the interactive calculator, Western Hemlock is already loaded with its verified shrinkage data.
Open the wood movement calculator →Managing Western Hemlock movement in a build
Wood moves across its width, not its length, so the wider the panel, the more it matters. The classic precautions apply: let the wood acclimate to your shop before building, attach wide tops with fasteners that allow movement (elongated screw holes, buttons, or figure-8 clips), avoid gluing solid panels rigidly across the grain, and account for seasonal swing in fitted parts like drawers and doors. For Western Hemlock specifically, its moderate movement means standard practice is usually enough.