CutMath

Teak

Tectona grandis · hardwood · Southeast Asia · low movement

Field data
  • Janka hardness 1,070 lbfred oak ≈ 1,290 lbf
  • Density ≈ 38 lb/ft³specific gravity 0.55 at 12% MC
  • Shrinkage — tangential 5.8%flatsawn width, green → ovendry
  • Shrinkage — radial 2.5%quartersawn width
  • T/R ratio 2.3 : 1higher = more cupping in flatsawn stock

Shop notes Oily, silica-laden, and nearly weatherproof — the boat-deck standard. Wipe glue surfaces with solvent first, and expect the silica to dull steel fast.

Seasonal movement at a glance

Width change for teak across a typical indoor year — 6% moisture content in the heated winter to 12% in a humid summer:

Board widthFlatsawnQuartersawn
6″ 1/16″ (0.075″) 1/32″ (0.032″)
12″ 5/32″ (0.149″) 1/16″ (0.064″)
24″ 5/16″ (0.298″) 1/8″ (0.129″)
36″ 7/16″ (0.447″) 3/16″ (0.193″)

Run your own numbers

Different width, different climate swing — the calculator below is preset to teak:

Board & conditions
Grain
Conditions given as

Typical swings:

Movement estimate
    Estimate Figures use species-average shrinkage from the USDA Wood Handbook and the standard shop movement formula. Individual boards vary — leave margin, especially with flatsawn stock.

    Teak questions

    How much does teak move with the seasons?

    A 12″-wide flatsawn teak board moves about 5/32″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 1/16″. Its tangential shrinkage is 5.8% and radial 2.5% (green to ovendry) — a low-movement wood.

    How hard is teak?

    Teak rates about 1,070 lbf on the Janka scale — softer than red oak but sturdy (red oak is roughly 1,290 lbf). Density runs about 38 lb/ft³ at indoor moisture levels.

    Is teak good for wide panels and tabletops?

    Carefully. Its tangential-to-radial ratio of 2.3:1 makes flatsawn boards prone to cupping — choose quartersawn stock for wide glue-ups, alternate growth rings, and fasten tops so they can slide.

    Similar species

    African Mahogany (Khaya) · Southern Red Oak · Southern Magnolia · American Holly · Chestnut Oak · Black Walnut

    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.