Sweetgum
Liquidambar styraciflua · hardwood · Southeastern US · high movement
- Janka hardness 850 lbfred oak ≈ 1,290 lbf
- Density ≈ 36 lb/ft³specific gravity 0.52 at 12% MC
- Shrinkage — tangential 10.2%flatsawn width, green → ovendry
- Shrinkage — radial 5.3%quartersawn width
- T/R ratio 1.9 : 1higher = more cupping in flatsawn stock
Shop notes Interlocked grain with a satin sheen; the heartwood ("redgum") can be striking. Notorious for twisting as it dries — buy it dry and sticker it flat.
Seasonal movement at a glance
Width change for sweetgum across a typical indoor year — 6% moisture content in the heated winter to 12% in a humid summer:
| Board width | Flatsawn | Quartersawn |
|---|---|---|
| 6″ | 1/8″ (0.131″) | 1/16″ (0.068″) |
| 12″ | 1/4″ (0.262″) | 1/8″ (0.136″) |
| 24″ | 17/32″ (0.525″) | 9/32″ (0.273″) |
| 36″ | 25/32″ (0.787″) | 13/32″ (0.409″) |
Run your own numbers
Different width, different climate swing — the calculator below is preset to sweetgum:
Typical swings:
Sweetgum questions
How much does sweetgum move with the seasons?
A 12″-wide flatsawn sweetgum board moves about 1/4″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 1/8″. Its tangential shrinkage is 10.2% and radial 5.3% (green to ovendry) — a high-movement wood.
How hard is sweetgum?
Sweetgum rates about 850 lbf on the Janka scale — softer than red oak but sturdy (red oak is roughly 1,290 lbf). Density runs about 36 lb/ft³ at indoor moisture levels.
Is sweetgum good for wide panels and tabletops?
Yes, with normal precautions: its 1.9:1 tangential-to-radial ratio is moderate. Still fasten solid tops so they can move across their width.
Similar species
Black Ash · Bigleaf Maple · Slippery Elm · American Elm · Hackberry · Water Tupelo
Shrinkage, specific gravity, and hardness from the Wood Handbook, FPL-GTR-282 (2021 edition), USDA Forest Products Laboratory (public domain). Values are species averages — individual boards vary with growth conditions and how they were dried.