PIR floor insulation boards provide high thermal performance without requiring the depth of many bulkier insulation products. That makes them useful in renovations, extensions and new-build floors where heat loss and available build-up height both matter.
Browse Soundproofing King's thermal insulation boards and rolls while comparing the options below.
What is PIR floor insulation?
PIR is a rigid closed-cell insulation board used in floors, roofs and walls. Its low thermal conductivity allows strong thermal resistance at relatively modest thicknesses. The exact thickness needed depends on the floor construction and target U-value, so the specification should be calculated for the project rather than selected from a generic rule.
Where PIR floor board is used
- solid floors beneath suitable screed systems;
- suspended timber floors where the construction is designed for rigid board;
- extensions and refurbishments with restricted build height;
- new-build floors designed around a target U-value;
- some underfloor-heating constructions where the heating-system manufacturer permits the selected insulation build-up.
Soundproofing King PIR options
Celotex GA4000
Celotex GA4000 PIR insulation board is a general-purpose foil-faced PIR range used across suitable floor, wall and roof applications.
Ecotherm Eco-Versal
Ecotherm Eco-Versal is another foil-faced PIR option for suitable building-envelope applications.
Insulated plasterboard
Where the requirement is internal wall lining rather than a floor board, Tekwarm PIR insulated plasterboard combines PIR insulation with a plasterboard facing. It is not a substitute for plain PIR floor insulation but is useful when insulation and an internal lining need to be installed together.
What should you compare?
Thermal conductivity and thickness
Lower thermal conductivity means less heat passes through a given thickness. However, board thickness, joints, perimeter detailing and thermal bridges all affect the finished floor performance.
Compressive strength
If insulation sits beneath a loaded floor construction, make sure the board is appropriate for the expected load and the specified screed or floor system.
Moisture and membranes
Moisture control is a whole-floor issue. PIR's closed-cell structure does not remove the need for the correct damp-proof or vapour-control layers where the construction requires them.
Fire and system compatibility
Check the exact product data and complete floor specification. Fire performance belongs to the whole construction, not merely the insulation board in isolation.
PIR vs mineral wool in floors
PIR and mineral wool are not interchangeable products. PIR is usually selected when high thermal resistance and limited depth are priorities. Mineral wool can offer useful thermal and acoustic properties in constructions designed for a fibrous infill.
If the project is mainly about impact or airborne floor noise rather than heat loss, start with our floor soundproofing range instead of assuming a thermal PIR board will solve the acoustic problem.
Underfloor heating
Insulation beneath underfloor heating can reduce downward heat loss, but the correct board and fixing arrangement depend on the heating system, substrate and floor finish. Read our underfloor heating insulation board guide for more detail.
Installation points
- Keep board joints tight and follow the specified joint treatment.
- Cut accurately around services and perimeter details.
- Do not guess the required thickness from another project.
- Follow manufacturer guidance for the substrate and floor system.
- Maintain the required damp-proof, vapour-control and fire details.
Choosing the right board
Start with the floor type, target U-value, available depth and expected load. If you need help sourcing the correct PIR thickness or comparing current options, contact Soundproofing King with the project details and delivery postcode.
