The Aluminium Rooflight Estimating Calculator estimates the materials, labour and plant required to fit an aluminium rooflight in a flat roof.

To estimate an Aluminium Rooflight, first select a rooflight from the Roof Light selector then enter the number of rooflights. For example, if you were estimating two rooflights of the same size and specification, you would enter 2. This multiplies all materials, labour and other associated resources by two and subsequently doubles the cost.

Review the dimensional information for the rooflight, paying particular attention to the trimmers and steelwork. These resources are highly variable depending on the roof structure so must be carefully considered. Also pay careful attention to the labour allowed for the various stages of construction.

The combination of information taken from the specification and the dimensions you enter will be used to calculate the following items:

  • Timber trimmers and upstand
  • Rooflight
  • Fixings
  • Steelwork
  • Plasterboard and finish
  • Decoration
  • Plant to lift steelwork
  • Plus the labour associated with the above

This Estimating Calculator is linked to the Specification.


  • The roof waterproof finish is dealt with in the relevant roof Estimating Calculator – either the Rectangular Flat Roof or Universal Flat Roof Estimating Calculator.