All species / American Elm

American Elm (Ulmus americana)

Bent parts, chair seats, boxes and rustic furniture; interlocked grain resists splitting.

The data

Stiffness (modulus of elasticity)1,340,000 psi

Specific gravity (12% MC)0.5

Janka hardness830 lbf

Average dried weight35.0 lb/ft³

Shrinkage, radial (green → dry)4.2%

Shrinkage, tangential9.5%

Shrinkage, volumetric14.6%

Movement classLively — plan real allowances

Stiffness & hardness: USDA Wood Handbook (Table 5-3 class data). Shrinkage: USDA Wood Handbook. Full sourcing notes are in our data documentation on the guides page — values print with their source so you can check us.

Shelf span guide — American Elm

Longest span that stays at or under the 0.02 in/ft long-term standard, floating ends, load spread evenly:

Shelf	15 lb/ft	25 lb/ft	35 lb/ft
3/4 in thick, 11 in deep	32 in	27 in	24 in
1 in thick, 11 in deep	43 in	36 in	33 in

Quick sag check — American Elm

Span (in)

Depth (in)

Thickness (in)

Total load (lb)

Full options — edging strips, fixed ends, centered loads — in the Shelf Sag Calculator.

Quick movement check — American Elm

Width across grain (in)

Cut

From MC (%)

To MC (%)

Full options in the Wood Movement Calculator.