Touchwood Homes

Strip Foundations

Our Touchwood Homes Strip Foundation detail uses conventional building methods to create a thermal-bridge free foundation system which can be built by your local diligent groundworks contractor. In order to achieve the enhanced performance required for an energy efficient home, our simple solution to prevent the thermal-bridging from the outside is to add a 150-100mm polystyrene sheet between the block-work skins, and a 300mm layer of insulation underneath the slab, so that all cold-bridging to ground is minimised.

Work sequence diagrams

insulated foundation

  • Excavate and pour concrete to required level
  • Lay external blocks and brickwork to finished floor level (FFL) smooth internal face.
  • Lay internal skin to required level and in-fill with lean mix or sand
  • Install 600mm DPC  cut and taped neatly into corners
  • Lay DPM on consolidated hardcore/ sand blinding
  • Tape DPM to DPC
  • Lay Marmox Thermo block and 1 course of lightweight blocks to suit.
  • Install 300mm EPS
  • Install separating layer
  • Install any under-floor heating pipes and reinforcing steel
  • Lay concrete slab to power-float finish.

The diagram below shows how the foundation goes together, to create a thermally bridge free detail:

nolabel 1 stable

Foundation / floor for non-shrinkable soil
of adequate bearing capacity.

Click on the image for technical detail.

edge detail shrinkable subsoil no labelsl 2015 01 21

Foundation / floor for shrinkable soil.

Click on the image for technical detail.

 Strip advantages:

  • Conventional build method can be done by your local ground workers
  • Good amount of concrete thermal mass in floor.
  • Floor is final finish, no need for follow on screed
  • Works on shrinkable clay soils using beam and block
  • Can be used with ground conditions requiring piling
  • Generic solution suitable for most situations


  • Whilst the methods are normal building practice our sequence of work must be followed and monitored to ensure correct installation without thermal bridges.
  • Depth of dig is defined by building control officer which relates directly to the amount of concrete to be used in the foundation and the amount of spoil to be removed from site.