Choosing Insulation: Batt, Mineral Wool or Rigid Board

Start with what the assembly has to do

Insulation is asked to do several jobs at once: slow heat transfer, resist fire, absorb sound, and stay dry. Different products are better at different ones, so start from the requirement rather than the price list.

Fibreglass batt

Cost-effective, widely available and straightforward to install in standard stud cavities. Fibreglass batt is the default for many residential and light commercial applications, and performs well when installed without gaps or compression.

Mineral wool

Higher density, non-combustible, water-repellent and notably better at sound absorption. Mineral wool costs more but is the right call for fire-rated assemblies, acoustic partitions and exterior applications where moisture is a factor.

Rigid board

Provides continuous insulation outboard of the framing, reducing thermal bridging through the studs — which is exactly what current energy codes push toward. Common in exterior wall assemblies and under EIFS.

Installation quality decides performance

A premium product installed with gaps, compression or missed corners underperforms a modest product installed correctly. Continuity is everything, which is why we treat installation quality as part of the specification, not an afterthought.