The Openings to Existing Walls Estimating Calculator calculates the Materials, Labour and Plant required to form openings to existing walls for the installation of windows or doors.

To complete an estimate in the Openings to Existing Walls Estimating Calculator, enter the dimensional information and the following items will be allowed for automatically:

  • Forming Openings
  • Lintels
  • Cavity Closer
  • Plant to form Opening
  • Disposal of Spoil

You can estimate multiple openings of the same size and specification by entering the number when prompted.


Before accepting the output, you should check all the pre-specified items, and in particular any items that are highlighted in red to show that they are “critical items” which are listed in the Calculated and Sundry Resources tabs.