A straw board (Dutch: halmplank) is a building panel made by compressing straw (stalks) under high pressure and wrapping it in sturdy layers of paper or cardboard. The panel was sold under trade names such as Stramit and used as a roof, wall, or ceiling board. It is an organic, natural panel.
Characteristics
The straw board owes its properties to the compressed straw:
- Insulating — a panel about 6 cm thick has a thermal resistance of roughly 0.6 m²K/W, with a thermal conductivity of around 0.1 W/mK
- Light and rigid — the pressing creates a firm but lightweight panel
- Moisture-sensitive — the main drawback is its sensitivity to moisture, which can reduce its strength; use in dry, draught-free spaces is therefore important
- Organic — the panel is built from renewable raw materials
Applications
The straw board was, and still is, used in various ways:
- Ceiling board — as a finish for attic and floor ceilings
- Wall board — as a lightweight partition or interior wall lining
- Roof sheathing — as a substructure beneath the roof covering
- Sustainable building — today the straw board is regarded as a “green” material and is valued for its natural origin and low environmental impact
Straw boards are still regularly encountered when renovating older houses. Modern, tightly finished construction methods with fewer gaps also reduce the risk of moisture damage.
Related terms
- Insulation
- Roof sheathing
- Sustainable building
- Ceiling
- Thermal resistance
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