Reference

MDF vs plywood vs pine: which material for your shelves?

The short version: Kamba builds in MDF, plywood, or pine. MDF is the cheapest and smoothest but dislikes moisture. Plywood is lighter than MDF and comparable to it in stiffness. Pine is solid wood with a natural look, the stiffest of the three and moderately priced. For everyday 18 mm shelving, any of the three works; for wide shelves or heavy loads, pine beats MDF.

Figures for France, where 18 mm MDF is on sale. Your country may stock different boards, and the builder tells you which spans yours allow.

The key difference: stiffness

Stiffness is what stops a shelf sagging. For the same thickness, pine is about three times as stiff as plywood or MDF, so it holds a longer span or a heavier load before it bows. Plywood and MDF are comparable.

Property	MDF	Plywood	Pine
Stiffness (resists sag)	Low, comparable to plywood	Low, comparable to MDF	Highest
Weight	Heaviest	Light	Light
Cost	Lowest	Highest	Moderate
Look	Paint only	Paint, or clear-finished edges	Natural wood, stain or paint
Edges	Smooth, paint-ready	Need edge-banding	Solid, sand and finish
Moisture	Poor (swells)	Better	Moderate (seal it)
Screw holding	Fair	Good	Good

When to use each

MDF: everyday shelving, light to medium loads, painted finishes, a tight budget. Keep spans shorter.
Plywood: damp rooms, and a lighter board than MDF for a comparable stiffness.
Pine: you want a natural wood look, a solid feel, and a good stiffness-to-cost balance. Watch for knots and let the boards acclimatise before building.

As a rule: if 18 mm MDF is not enough for your width and load, switch to pine or a thicker 25 mm board.

See standard shelf dimensions

How Kamba uses this

Kamba lets you choose MDF, plywood, or pine, and calculates your design for the material you pick. It recommends one per furniture type: MDF for a shelving unit, where a divider shortens the span so the cheaper, smoother board is enough; pine for an alcove built-in, which is fitted on three sides with no divider, so a stiffer board carries the open span. Every material stays selectable, and Kamba checks the span and load for your exact choice; if the span exceeds the limit, it recommends a stronger material or a thicker board.