Rockwool vs PIR Insulation: What’s the Difference?
Rockwool and PIR are both insulation materials, but they are different products with different properties and uses.
Rockwool is mineral wool insulation, while PIR is supplied as a rigid insulation board.
The right choice depends on the construction, available space and the performance required.
What Is Rockwool?
Rockwool is mineral wool insulation.
TSAR supplies Rockwool RWA45 acoustic insulation batts in several thicknesses.
Mineral wool products are commonly chosen where thermal, acoustic and fire performance are important considerations.
What Is PIR Insulation?
PIR, short for polyisocyanurate, is a rigid foam insulation commonly supplied as boards. Different products are designed for particular wall, floor and roof applications.
Check the exact product name and intended use, rather than choosing by brand alone. Manufacturers can supply several different insulation materials.
For example, Kingspan Kooltherm K103 Floorboard is phenolic insulation, rather than PIR. It should be compared using its own product data and installation requirements.
What Is the Main Difference?
| What to compare | Rockwool stone wool | PIR boards |
|---|---|---|
| Product format | Stone wool products, including the RWA45 slabs supplied by TSAR | Rigid foam boards |
| Thermal performance | Check the thermal conductivity and thickness of the specific product | Check the thermal conductivity and thickness of the specific product |
| Sound performance | Check the product’s role in the specified acoustic construction | Do not assume a thermal board provides the same acoustic performance |
| Fire performance | Check the declared product classification and complete system | Check the declared product classification and complete system |
| Suitable applications | Depend on the particular stone wool product | Depend on the particular PIR board |
The same thickness of two different insulation products does not necessarily provide the same thermal performance.
Choose according to the specified wall, floor or roof construction, including any acoustic and fire requirements.
Which Should I Use?
Check:
Where the insulation is being installed
Required thickness
Required thermal performance
Acoustic requirements
Fire requirements
The specified wall, floor or roof construction
If a particular insulation product is shown on the drawings or specification, follow that requirement.
Related Building Advice
How Much Loft Insulation Do I Need? →
What Thickness of Loft Insulation Should I Use? → future page
Need Loft Insulation?
Send Andy and the TSAR team the product specified, required thickness, quantity and delivery postcode.
If you are comparing options, tell us where the insulation will be used and share any relevant project specification. We can help you check product availability and delivery across London and Greater London.