What drives the cost of a steel structure? A plain guide to our estimate

When you request a quote on our website, you get a preliminary estimate broken down into itemised cost heads. Transparent pricing is one of the reasons clients work with us, and it only helps if you understand what each line means.

This guide walks through each part of the estimate, what drives it, and which decisions you can make that change it.

It starts with steel weight

Almost every steel structure estimate comes back to one number: the total weight of steel in the frame, in kilograms. Material, fabrication and installation are all priced by weight, so it is the single biggest driver of cost.

If you already know the steel weight, for example from an engineer's material schedule, you can enter it directly. If you do not, our estimator works out an allowance from the building's footprint (length × width), using a typical weight per square metre. That figure is flagged as estimated, and it is one of the first things our engineers firm up when they review your project.

What makes a frame heavier?

• Span: wider clear spans need deeper, heavier rafters.
• Eaves height: taller columns are longer and must resist more wind.
• Loads: cranes, mezzanines, roof-mounted equipment and solar panels all add steel.
• Bay spacing: fewer, wider bays mean fewer frames, but each one works harder.

The cost heads, line by line

Steel material

The cost of the structural steel itself, calculated from the steel weight.

Fabrication

The workshop work of cutting, drilling, welding and finishing the members, also priced by weight. Complex connections and many small pieces take more workshop time than simple, repetitive frames.

Installation

Erecting the frame on site: lifting, aligning, bolting and bracing, again priced by weight. Difficult access, restricted sites or working around an operating building can add to this.

Roofing

If you choose a roof sheeting type, the estimate includes the sheet material and its installation, priced per square metre of roof area. Roof area is calculated from the footprint with an allowance for the roof pitch, or you can enter your own figure. The sheet type you choose makes a real difference to this line.

Cladding

Wall cladding works the same way. The wall area is worked out from the building's perimeter and eaves height, or entered directly, and priced with the cladding type you choose. Buildings with open sides or masonry walls may need little or no cladding.

Civil works

If you tick civil works, the estimate adds an allowance per square metre of footprint for foundations and associated concrete works. This is the line most affected by site conditions. Soil type, slope and access all matter, so treat it as a guide until the foundations are designed.

Transportation

Getting fabricated steel from the workshop to your site. The estimate includes a standard allowance. Distant or hard-to-reach sites will be priced individually when we review your request.

Engineering and design

The structural design, calculations and drawings, calculated as a percentage of the steel material, fabrication and installation cost.

Extras

Items you select in the additional requirements step, such as doors, gutters or other accessories. Depending on the item, they are priced as a flat sum, per square metre of footprint or per metre of perimeter.

Contingency

A percentage added to the subtotal to allow for the unknowns that exist at this early stage. It is not padding. It reflects the fact that a preliminary estimate is made before drawings, a site visit and final quantities.

What the estimate is, and what it is not

The instant estimate is a preliminary figure for planning and budgeting. It is not a formal quotation. It is subject to engineering review, final quantities, drawings, specifications and site conditions. Very large projects are outside what an online estimate can sensibly cover, and the tool will ask you to contact us directly.

Once you submit your request, our team reviews it and follows up. Drawings, site photos and a clear description of how the building will be used all help us firm up the numbers quickly.

Decisions that change the cost

• Keep the brief clear. Knowing your required clear span, height and loads early avoids redesign later.
• Choose sheeting deliberately. Roofing and cladding choices affect both the price and the building's long-term performance.
• Plan for the future. If you may add a mezzanine or extend the building later, tell us now. Designing for it at the start costs less than strengthening later.

See your own numbers

The quickest way to understand the cost of your building is to run your own figures. Request a quote, enter your dimensions and scope, and you will see every cost head described here in a few minutes.