Thermalite 300mm trench blocks

£3.95 + VAT


Thermalite Trenchblock Tongue and Groove is an alternative to the construction of cavity walls with concrete infill, engineering bricks or heavy aggregate blocks for foundations. It is available as Hi-Strength Trenchblock (with compressive strength of 7.3N/mm2) and with tongue and groove joints and handholds for easy handling.


  • Improves thermal performance
  • Available in standard or with tongue and groove joints and handholds
  • Can be used in thin joint masonry, saving time and money
  • Removes the need to mortar perp ends
  • Moisture resistance

Key Data

Compressive Strength: 3.6 N/mm²

λ Design above dpc: 0.15 W/m.K

λ Below ground: 0.24 W/m.K

Dry Density: 600 kg/m³

Working Dimensions

Face dimensions (mm): 440 x 215