Hi-Therm Lintel | Psi W/m-K 0.05


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Hi Therm Lintels

Cavity widths from 90mm To 165mm






Blockwork built tight against inner face of the lintel. Place mortar bed on top of blockwork before floor units are laid to provide even distribution of load. Lintels may be propped to facilitate speed of construction. See Lintel Installation on page 6. Insulation fixed on top of the lintel has been cut back on this illustration for clarity.

Keystone leads the way with the development of a completely unique rangeof lintels to address the thermal requirements of new building regulations, which require that lintels should be assessed for their effect on the thermal performance of a building. The thermal performance of a lintel is expressed in terms of Psi Values (Ψ) i.e. linear thermal transmittance.

Psi 0.05 W/m-K

Hi Therm Lintels

Psi Comparison Chart

To help understand the immense thermal benefits of the Hi-Therm Lintel it must be compared to other lintel types.

PSI Values Hi Therm Lintels

Key Benefits

  • Up to 5 times more thermally efficient than cavity wall lintels.
  • The significant reductions in thermal bridging due to the GRP component will assist in the building design process to achieve compliance with Part L and The Code for Sustainable Homes.
  • The use of Hi-Therm will make a significant contribution to a buildings performance in respect of the Fabric Energy Efficiency Standards (FEES).
  • Outperforms Stainless Steel on price and
    corrosion resistance.
  • Hi-Therm has achieved the 1 hour fire resistance test as carried out by Exova Warringtonfire utilising the heating conditions of BS EN 1363-1 1999.

Design Features

  • Patented GRP and Galvanised Steel
    hybrid design.
  • Galvanised steel is used to support the heavier load on the inner leaf of the cavity wall.
  • Profiled CFC free insulation ensures the continuity of insulation.

Hi Therm Lintel loading figures Keystone Steel Lintels

Hi Therm Lintel loading figures Keystone Steel Lintels


Not required on Hi-Therm lintels. *Up to severe exposure.

Testing of Keystone’s Hi-Therm Lintel was carried out by the BRE (Building Research Establishment) using Physibel’s thermal analysis software TRISCO which complies with BS EN ISO 10211-1. The modeling follows the requirements of the BRE conventions document BR497.