No, phenolic insulation boards do not absorb water. Phenolic insulation has a very slow water absorption rate – it’s one of the product’s most desirable selling points (alongside its exceptional thermal efficiency, of course).

Phenolic insulation is both water and moisture resistant, preventing issues like mould and mildew growth, structural damage and a negative impact on its thermal performance. This will also help you to keep your space clean and sanitary with little maintenance.

Although water will damage them with prolonged submersion in water, temporary leaks shouldn’t harm the phenolic board you install in your building.