- The performance characteristics of the insulation material.
- The suitability of the insulant to its installed location.
- Adherence to manufacturer’s instructions.
- Quality of workmanship.
- Defects gaps in insulation, thermal bridging and moisture penetration.
- Cellulose.
- Cork board.
- Hempcrete.
- Woodfibre batts.
- Woodfibre board.
- Mineral wool batts.
- Extruded Polystyrene (XPS).
- Expanded Polystyrene (EPS).
- Insulation above the floor slab: Insulation is placed above the concrete slab, along with a separating/slip layer and then a rigid floor is generally either screed or boarding. The damp proof membrane (DPM), which can be either above or below the slab, must be continuous with the damp proof course (DPC) in the surrounding walls. The insulation boards must be tightly butted and sealed to limit air leakage. Heating response time is improved by having the insulation above the slab, and the insulation zone can be used to run services and underfloor heating. However, when used together with timber-based flooring it may be unsuitable for use in rooms that may get wet such as kitchens or bathrooms.
- Insulation below the floor slab: Insulation is placed below the concrete floor slab. There are fewer restrictions on the thickness of the insulation in comparison with above slab insulation, and there is less of an issue with point loading as the load is spread over the slab rather than the insulation. However, rooms are slower to heat by comparison with above slab insulation.
- Ground floor rooms meet the minimum room heights once the new levels have been set.
- Minimum U-values are achieved.
- The risk of fire from additional insulation material is minimised.
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