What to send a fabricator for an accurate steel quote
Send the right documents when you first contact a fabricator and you can usually expect a firm price within a few working days. Send insufficient information and what comes back is a ballpark figure, often prepared on assumptions that may not match the final design. This guide covers what fabricators actually need to price structural steelwork, staircases, balustrades, and bespoke metalwork accurately, and where responsibility for design and calculations sits.
General arrangement drawings
The most useful document is a set of general arrangement (GA) drawings produced or reviewed by a structural engineer. These show the overall layout, member sizes, span lengths, floor and roof levels, connection positions, and how the steelwork relates to the rest of the structure. Architectural drawings support structural steel work but rarely show enough detail for accurate pricing. A sketch or a written description of what you need will produce a rough budget figure at best.
If the design is still at an early stage, say so. A fabricator can flag buildability issues before the drawing set is finalised, which is more useful than having to revise a quote once significant changes are made. The opposite is also a problem: sending drawings labelled as preliminary while asking for a firm price creates a figure that will shift as the design develops.
3D CAD models are increasingly shared between designers and fabricators as a reference tool, but they do not replace 2D drawings. Steelconstruction.info’s guidance note GN 4.01 states that information on 2D drawings takes precedence where there is a conflict with the model.
Loading and structural information
A fabricator prices the steel, not its design. To quote accurately, they need the steel grade, section sizes, and connection types. Where the structural engineer has designed the connections, the connection drawings or engineer’s notes must accompany the GA drawings.
For bespoke items such as staircases and balustrades, loading requirements directly affect section sizes and connection details. The imposed loading on a residential staircase differs from that on a staircase in a public or commercial building. Where loading data is available, including dead loads, imposed loads, and wind loads, include it. A fabricator working without this information must either make conservative assumptions or go back for clarification, both of which delay the quote.
If a structural engineer has already checked the member sizes, send the calculations or at least the load summary. If not, flag that member design is still outstanding and confirm who will be carrying it out.
The specification
A complete specification states the steel grade, the required surface finish, and the execution class under BS EN 1090-2. All three affect cost, and leaving any of them open forces the fabricator to make assumptions.
The most common structural steel grades in UK buildings are S275 and S355, both specified to BS EN 10025. The designer chooses the grade based on member design. S355 is stronger and can sometimes allow lighter sections, but the grade must suit the welding requirements and execution class.
The finish should be stated explicitly: hot-dip galvanised, primer only, full paint system, or powder coated. Each has a different cost. If the steelwork is going external or into a corrosive environment, include the corrosivity category under BS EN ISO 12944, or describe the location and exposure in enough detail for the fabricator to advise.
The execution class should appear in the engineer’s documents. If it does not, BS EN 1090-2 assigns EXC2 by default, but it is better to have it confirmed explicitly. If the project may require EXC3, flag this before pricing, as it changes the quality management scope.
Site access and programme
Access matters more than most clients expect. A restricted city-centre site where unloading is limited to specific windows differs significantly from an open rural plot with turning room. Include the site address, any access restrictions, the available unloading window, and whether there are constraints on crane use. Height restrictions, weight limits on approach roads, and live building occupation around the site all need to be flagged upfront.
Share your programme if you have one. Fabricators manage workshop loading and material procurement weeks in advance. Steel supply lead times vary with market conditions, and early contact gives more flexibility. Late enquiries constrain what is achievable on programme.
For erection work, confirm who is responsible for structural bearings, setting-out checks, and temporary propping where required. These items need to be agreed before work begins, not resolved when the steel arrives on site.
Who is responsible for the design and calculations
In most commercial and residential projects, the structural engineer designs the members and takes responsibility for the structural calculations. The fabricator produces fabrication drawings from the engineer’s details and may also design the connections, or may receive connection designs from the engineer. Both arrangements are common; the key is that it is agreed and documented before pricing.
Where no structural engineer has been appointed, a fabricator cannot carry out member design or produce calculations unless they have their own in-house design capacity. Confirm who holds responsibility for member design, connection design, and structural calculations before the enquiry is sent. State this clearly in the enquiry documents. If the structural engineer is still to be appointed, say so.
CDM Regulations also require the steelwork contractor to provide an erection method statement supported by drawings. This is the contractor’s document, but it depends on design information being in place first.
What a fabricator cannot price without
| Missing information | Effect on the quote |
|---|---|
| No GA drawings | Budget figure only; major revision likely as the design develops |
| Steel grade not stated | Fabricator assumes S275 or S355; price changes if the design requires otherwise |
| Finish not specified | Fabricator assumes primer or leaves finish as a variable; galvanising adds cost |
| Execution class not stated | EXC2 applies by default; if EXC3 is required, the scope and cost will change |
| No access or programme details | Delivery logistics and erection cost cannot be confirmed; availability not checked |
| Design responsibility unclear | Items requiring engineering input cannot be priced; progress stalls |
To discuss a project or send through drawings, get in touch via twojsmetalwork.co.uk/contact-metal-fabricators.
Written by Two Js Metalwork
Structural steel fabrication and architectural metalwork in Sussex. See the projects behind the advice.
