MDF (Medium Density Fibreboard)

Family

Wood

Category

engineered

Density

0.75 g/cm³ · 750 kg/m³

The solid wood pages here carry a set of clear-wood figures — specific gravity, bending strength, stiffness, Janka hardness and shrinkage — because a species has measured properties that belong to the tree. MDF (Medium Density Fibreboard) has none, and not because the data is missing: it is manufactured. What it does under load belongs to the board and to the standard it was made to — the resin, the pressing, the grade — rather than to a species. Two panels sold under the same nominal product from different plants can differ by more than two species of solid timber do.

Density is the one figure that stays comparable with the solid species, which is why it is the number this page leads with.

A panel is a composite in the strict sense — a fibre phase in a binder — and this database does have a composites family. It is filed here instead because materials are grouped by their base material, and a board is wood.

Origin

Made from wood fibre and resin

Appearance

Uniform tan throughout, no grain or figure

Working

Machines to a smooth edge and takes paint without raising grain, but the fine dust is a health hazard and the panel swells irreversibly once it gets wet.

Unlike the USDA figures above, these lines are not measurements: they carry no units and no single source. They describe how the timber is generally found to behave rather than what it is guaranteed to do — read them as the consensus of the trade, not as a specification.

• Density varies with board thickness and manufacturer
• Swells permanently if it takes on water — not for wet areas
• Fine dust; extract at the tool

Dressed sizes are the same for every species — a 2x4 is 1-1/2 x 3-1/2 in in oak as much as in spruce. What changes is the weight, and that is derived here from mdf (medium density fibreboard)'s density of 0.75 g/cm³.

Which tools work a material is a property of the family (Wood), not of the individual species — so this list is the same on every wood page, and changes when the tool data changes rather than when this paragraph does.