How to write a brief a supplier can actually quote

By Johnny · 23 October 2026 · 6 min read

A typical first enquiry is three lines long and attaches nothing, or it is forty pages of architectural drawings with no statement of what the building is for. Both produce the same outcome: five prices that cannot be compared, and a week spent asking follow-up questions.

The brief below takes about twenty minutes to write if you already know your operation, and it converts an enquiry into a specification.

The nine lines

1. What the building is for

One sentence, plain language. “Storage of bagged cement, delivered by tipper and loaded onto customer trucks.” Not “warehouse”. The use decides loads, doors, ventilation, floor and envelope, and it is the only line that cannot be inferred from a drawing.

2. Where it is

Country and town, plus anything that changes design: coastal, high altitude, remote from a port, landlocked. Also state the design wind speed for the site in km/h, taken from the local code — and if you do not know it, say so explicitly rather than leaving it out. A supplier who has to guess will guess, and different suppliers guess differently.

3. Dimensions

Four numbers, and state whether each is fixed or negotiable:

• Span — across the width, and whether internal columns are acceptable.
• Length — total.
• Height — and say which height you mean: eave, ridge, or clear internal.
• Bay spacing — if you have a preference, otherwise ask them to state theirs.

4. Loads

What the structure must carry beyond its own weight and the roof:

• Roof: nothing, solar panels, a suspended conveyor, services, maintenance access.
• Crane: yes or no, capacity, and whether it is now or later.
• Mezzanine or suspended floor: yes or no, and the intended load.
• Any suspended equipment, hoppers or conveyors fixed to the frame.

5. The envelope

Single skin, insulated, or sandwich panel. Say whether the building is temperature-controlled, because that changes everything about the roof, the walls and the junctions. Say whether the roof must be walkable or carry maintenance access.

6. Openings

Every door and window with its size and type: roller, sliding, personnel, dock leveller. State where they must be — a loading dock in the wrong bay is a layout failure, and the bay grid is fixed early.

7. Site conditions

Ground: what you know about it, and whether a soil investigation exists. Access: width of the road in, and whether a large crane can reach the site. Both affect how the structure must be split for transport and lifting.

8. Scope boundaries

This is the line that most changes the price and is most often missing. State plainly what you expect the supplier to provide:

• Steel structure only, or structure plus cladding?
• Are foundations in or out?
• Erection on site: by them, by you, or by a local contractor?
• Delivery to which point — factory, port, or site?
• Drawings for approval: included?

Two quotes that differ by a wide margin almost always differ here, not in the steel.

9. Timing

When you need it on site, and whether that date is fixed by something external — a season, a funding milestone, a production start. This tells the supplier whether to quote a normal programme or to price acceleration.

What to attach

Attach a plan if you have one, and a site location. Do not attach forty sheets of architectural drawings in the first message: they slow the response and they invite the supplier to price only what they can see, which is usually the structure and not the rest.

If you have a soil investigation, attach the summary page. If you have photographs of the site, attach two — access and ground. Those are worth more than a set of drawings to someone judging how the building will be built.

What to leave out

• A target price. It anchors the answers and tells you nothing.
• A specification you copied from another project. It usually carries assumptions that do not fit this site, and it removes the supplier's chance to tell you that.
• “As per drawing” as a scope description. The drawing does not say what is excluded.

What a good reply looks like

A supplier who has actually read the brief will come back with questions before a number. Questions are a good sign, not a delay. The reply you want states:

• The grid they priced — span, bays, spacing.
• The design assumptions they used, including wind speed.
• What is included and, in its own list, what is excluded.
• The documents they will produce, and when.

If a quote arrives with a single number and no assumptions, you cannot compare it to anything, and you cannot tell later whether a change is a change or something that was never in scope.

The mistake I see most

Writing the brief from the building outwards instead of from the operation inwards. The operation is fixed and cheap to describe. The building is flexible and expensive to change. Describe the operation, state the constraints, and let the structure follow — that is the direction in which information should flow.