Terms of use
Last updated: 10 September 2026
The tools on this site are free and are meant to help you budget and order. They are not a quote, not a design, and not a substitute for someone standing on your site.
What the calculator actually does
It works out quantities from the dimensions you enter. The volumes and areas are geometry, so they are exact for the numbers you typed — but they are only as good as those numbers. Guess your topsoil depth or your fall and the answer will be wrong in proportion. Dig a trial hole and measure.
It also applies working assumptions — a concrete waste allowance, a compaction factor for Type 1, bulking factors for dug material, a lorry capacity for muck-away. These are sensible trade figures, not guarantees. Site conditions vary, and so does what a particular supplier will deliver.
What it deliberately leaves out
Pad foundations. The concrete bases the stanchions sit on are sized by a structural engineer against your span, eaves height, wind loading and ground bearing capacity. There is no formula that can do it from a web page, so we don't pretend otherwise. Anyone giving you a pad size without a design has guessed it.
The calculator is not engineering advice and must not be used in place of a structural design, a ground investigation, or a building control submission.
Check before you order
Confirm quantities with your groundworker, your ready-mix plant and your quarry before placing an order. We are not liable for material ordered, over-ordered or under-ordered on the basis of these figures, or for any loss arising from relying on them.
We are not the supplier
Cornwall Steel Buildings does not manufacture, supply or erect steel buildings. Enquiries are passed to a steel building supplier who will contact you and quote you directly. Any contract for a building is between you and them, on their terms, and we are not a party to it.
This site
The content, tools and calculations on this site belong to us. Use them freely for your own projects. Do not copy the site or republish the tools as your own.
Nothing here limits liability for death or personal injury caused by negligence, or for fraud. These terms are governed by the law of England and Wales.