Disclaimer

The calculators give estimates for rectangular areas from the figures you enter. They do not design structures.

Spans, support spacing, loads, barriers and approvals must come from manufacturer documentation, the applicable standards (such as the NCC and AS 1684 in Australia, or the Building Regulations in the UK) and qualified professionals.

Prices change. Every price on the site shows the date we checked it, so confirm it with the seller before you buy.

Planning and building rules differ between England, Scotland, Wales and Northern Ireland, and between Australian states and councils.