Steel building groundworks calculator

A frame quote prices the frame. The base underneath it is a separate job — and on a sloping field it is rarely the smaller number. Put your building size in and this works out what you need to order.

Building

What is it for

Tractors and trailers on and off it daily.

Span

Length

Slab

Slab thickness

Set by the building type above. Change it if you know different.

Slab oversail past the frame

Each side. Leave at 0 if it finishes flush.

Reinforcement

Sub-base depth, compacted

Site

Fall across the site

High corner to low corner.

Finished level

Balanced keeps the dug material on the plot and moves the least.

Topsoil depth

Dig a trial hole and measure it. This shifts more muck than the slope does.

Ground underneath

Spoil goes off siteLeave unticked if you are spreading or heaping it on the holding.

Concrete to order for the slab

52.0m³waste allowed, rounded to the half metre

Machinery store · slab 246.4 m² at 200 mm · working platform 352.6 m²

Ready-mix plant

Slab concrete

Net 49.3 m³ before waste

52.0m³

Quarry

Type 1 sub-base

Spread 188 mm loose to finish at 150 mm compacted

77.6t

Builders merchant

Mesh sheets

2.4 × 4.8 m sheets, 300 mm laps allowed

28sheets

Damp proof membrane

Laps and upstand included

276m²

Edge detail

Perimeter, for edge insulation or expansion joint

64.8m

Earthworks

Topsoil to strip

110.2 m³ once dug and loose

88.2m³

Cut

17.6m³

Fill

17.6m³

What this does not work out: the pad foundations

The concrete pads the stanchions sit on are sized by a structural engineer, not by a formula. They change with the span, the eaves height, the wind loading on your particular site and what the ground will bear. Anyone quoting you a pad size without a design has guessed it.

Want this priced properly?

Send us the job and we'll get you engineered drawings and a quote for the frame — with the pad sizes this tool can't work out. The figures above go with your enquiry, so you don't have to type them again.

Your name

Phone

Anything else about the job

Every enquiry gets a reply the same day, and your figures are sent with it. We are not a steel building manufacturer — we pass your details to a steel building supplier so they can price the job and contact you. How we handle your details.

Want to check the working?

Every assumption behind these figures is published with its range — waste allowances, bulking factors, compaction, lorry capacity — along with the maths behind the cut and fill.

How the calculator works