The Timber Frame Panel Estimating Calculator should be used in conjunction with the Site Fab Timber Frame Spec to estimate timber frame panels for external walls, where the timber frame is constructed on site.

The Timber Frame Panel Estimating Calculator calculates:

  • Structural timbers
  • Ply facings
  • DPM and breather membranes
  • Insulation
  • Fixings
  • Plus all labour associated with the above

You can use the Timber Frame Panel and Timber Frame Panel for Gable Estimating Calculators to replace the internal leaf of blockwork of conventional external cavity wall construction with timber frame panels.  

The diagrams below illustrate how external Timber Frame Estimating Calculators work in conjunction with external wall Estimating Calculators:

Standard Brick & Block Cavity WallCavity Wall with Internal Blocks & Insulation OmittedCavity Wall with Timber Frame & Insulation Added

You can build a complete timber frame using a combination of the Timber Frame Panel, Timber Frame Panel for Gable, Internal Timber Frame Studding and Internal Timber Frame Studding for Gable Estimating Calculators.


  • The Timber Frame Panel Estimating Calculator should be used in association with the various external wall Estimating Calculators, including Brick And Block Cavity Wall, Cavity Block Wall and Stone Cavity Wall. The timber frame panel takes the place of the internal leaf of the block wall.
  • You must ensure that the inner leaf for each block wall is set to "Included in timber frame" in the respective wall Estimating Calculators.
  • The plastering to the internal face of the timber frame, where required, is assumed to be incorporated in the relevant external wall Estimating Calculator.
  • The Timber Frame Panel Estimating Calculator is NOT linked to the Specifications.
  • If you are purchasing a full timber frame kit, you should select the Timber Frame Spec and add the cost of the kit to your estimate as a lump sum in the Subcontract Quotation Estimating Calculator.