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Concrete, beam and block floors

Key Properties


  • does not readily absorb water, making it suitable for use in damp environments;
  • is light, robust and easy to handle; it may be worked using a saw or sharp knife;
  • is durable and will perform for the service life of the building.

Meeting Regulations

Required thicknesses of QUINN-therm QF (mm)
Required U-value (W/m2K) P (exposed perimeter, m) / A (floor area, m2)
  0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
0.37 25 25 25 30 30 35 35 40 40 40
0.25 25 50 65 70 75 75 80 80 80 80
0.22 25 30 50 60 65 70 70 75 75 75
0.20 30 60 75 80 85 85 90 90 90 90

* The above table is a guideline - contact Quinn Technical Services department for more information.
Results based upon floor construction of:
suspended concrete beams infilled with concrete blocks, QUINN-therm QF, 60mm cement:sand screed (floor finish omitted).
Calculations performed to BS EN ISO 13770.

Design Notes

  • where a Radon barrier is required it should be laid over the grouting layer and extended across the wall cavity to the outer leaf.
  • extend cavity wall insulation at least 150mm below the top of the floor insulation slab to reduce thermal bridging at the wall/floor junction.
  • subfloor ventilation is required to prevent problems with damp.
  • lay a polyethylene separating layer over QUINN-therm boards to prevent moisture from the screed penetrating board junctions and causing movement.


QUINN-therm QF (Quinn Floor) is a PIR (polyisocyanurate) insulation board intended for use in suspended floors of beam and block or pre-cast concrete units.

QUINN-therm consists of a core of PIR foam bonded on both faces to composite metalised facings; the gas filled cells give QUINN-therm its high thermal performance and strength.

Suspended floors are quick to construct and are suitable for use where site conditions preclude the use of groundbearing floors, and are formed of concrete units, above a vented void. To achieve required energy efficiency standards they should be insulated above the structural floor and below the finish or screed. The insulation must be strong enough to withstand the dead and imposed loads without deflection.

QUINN-therm QF is ideal for insulating suspended floors: it is strong, moisture resistant and has a very low thermal conductivity, which minimises the thickness required to meet regulations and cuts down the increase in floor thickness which has to be accommodated.

Installation Guidance

  1. Level the surface of the beam and block floor with grout and/or a levelling topping.
  2. Lay QUINN-therm QF boards in broken bond; butt tightly together.
  3. Overlay with polyethylene slip sheet. Lap edges and turn up at perimeters.
  4. Install sheet flooring. Leave a 10mm expansion gap to the wall at perimeters.


  • Build partition walls directly off the structural floor or timber battens: do not build walls off QUINN-therm QF.
  • Install timber battens at thresholds, foot of stairs and beneath kitchen and sanitary fittings to prevent deformation of the floor by high point loadings.
  • Cut QUINN-therm QF to fit neatly round penetrations.
  • Ensure QUINN-therm QW cavity wall boards extend below the level of the floor insulation to prevent thermal bridging.

Handling and Storage

QUINN-therm QF boards are supplied in shrink-wrapped packs. Store boards under cover and out of direct sunlight, keeping boards flat.

When handling QUINN-therm QF do not knock corners and edges. Cut QUINN-therm QF with a fine tooth saw or trimming knife.

Product Data
Properties Value QUINN-therm QF
Board width x length mm 2400 x 1200**
Board thickness mm 20 - 200
Board density kg/m3 26 - 32
Area per board m2 2.88
Edge profiles available   Butt edged
Performance Data
Properties Value QUINN-therm QF
Thermal conductivity* W/mK 0.022 - 0.023
Water vapour resistivity MNs/gm ~ 400
Compressive strength kPa >120

* quoted in accordance with BS EN 13165:2001 ‘Thermal insulation for Buildings - factory made polyurethane foam products’.
** other sizes may be available upon request.

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Fax : +353 49 9525601

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