KORE Loft Attic Insulation Flooring System is specifically designed to allow the floor of the attic to be insulated and still use the space for storage. The product is essential for ensuring there is safe, secure access from the attic hatch door to the water tank and other services in the attic. KORE Loft comprises of one composite sheet of silver expanded polystyrene insulation bonded to an 18mm tongue and grooved chipboard sheet. The sheets sit on top of the joists in the attic and slot together to form a floor for access and storage. A suitable insulation material is also installed between the joists at ceiling level to ensure the required U-values are achieved.

You can view and download the KORE Loft Insulation Design Guide or view all technical documents on the KORE Resource Centre.




Key Features

  • Excellent thermal performance for the lifetime of the building
  • Sheets are tongue and grooved for easy installation
  • Meets and exceeds current Building Regulations
  • Exceptional compressive strength
  • Dual purpose solution - attic insulation and attic storage
  • Maintenance free

KORE Loft U-Value Calculations

All U-value calculations are in accordance with BS EN ISO 6946:2007. An inhomogeneous layer was considered in all calculations where the insulation runs between the timber joists. The timber centres were taken as 400mm. Please contact our technical team team calculations at different centres. It is assumed that the insulation is fitted accordingly and the correction factor for air gaps has been ignored. The thermal conductivity of the mineral wool product was taken as 0.044 W/mK.

KORE Loft Attic Insulation - Detail 1: Insulation at Ceiling Level

KORE Loft EPS70 Silver Mineral Wool (mm) U-Value W/m2K
70 150 0.16
95 100 0.16
95 150 0.14
110 150 0.13

Building Standards

KORE Loft Insulation can satisfy the requirements of the Irish Building Regulations as outlined in:

  • Part L - Conservation of Fuel and Energy - Dwellings (2011)
  • Part L - Conservation of Fuel and Energy - Buildings other than Dwellings (2008)

Design Standards

  • BS 5250: 2012 Code of Practice for the control of condensation in buildings
  • NSAI S.R. 54: 2014 Code of Practice for the energy efficient retrofit of dwellings

Ventilation and Control of Condensation

With insulation installed at ceiling level there is a risk that condensation will form on the surfaces of the cold side of the insulation in the loft space. This condensation occurs when warm moisture laden air is able to pass to the cold loft space but is prevented from dissipating into the external atmosphere by the roof structure. Steps must first be taken to prevent the formation of condensation and the passage of warm air and water vapour from passing through the structure into the cold loft space. Condensation can be prevented by ensuring the ceiling is well sealed and ensuring the cold side of the insulation is ventilated. A vapour control layer should be installed between the insulation and the plasterboard on the warm side of the insulation to control water vapour. 

Product Technical Details

KORE Loft Insulation is supplied as EPS70 as defined in IS EN 13163:2012. Other densities and grades are available upon request. Reaction to Fire Class E, containing a flame retardant additive.


KORE Loft EPS70 Silver: 15kg/m3

Thermal Conductivity

The thermal conductivity of KORE Loft Insulation products are in accordance with IS EN 13163:2012 and EN12667 Thermal performance of building materials and products - determination of thermal resistance by means of guarded hot plate and heat flow meter method.

  • KORE Loft EPS70 Silver: 0.031W/mK

Thermal Resistance

Thermal resistance, known as the R-value, varies with the thickness of the insulation. To calculate the thermal resistance (m2.K/W) divide the thickness of the insulation by its thermal conductivity and round down the result to the nearest 0.05.

  KORE Loft EPS70 Silver
Insulation Thickness (mm) Thermal Resistance (m2.K/W)
70 2.26
95 3.06

Declaration of Performance Certificates

KORE Loft EPS70 Silver


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