How to estimate a steel building
To estimate a steel building, first define what the offer includes, then assess quantities and costs for materials, fabrication, external services, transport and erection. Add allocated project overheads before setting the selling price. An isolated price per square metre does not describe these assumptions.
TopSteel team — Oweo SASPublished on
A guide published by Oweo SAS, the company behind TopSteel.
1. Define the work before looking for a price
Gather dimensions, intended use, location, frame scope, roofing, cladding and openings. Record known site access and erection constraints, outstanding decisions and exclusions. Commercial estimating does not replace structural design or technical approval. Structural assumptions need to be established by the appropriate project professionals.
2. Build a checkable quantity basis
Separate sections, plates, connections and other components. Keep a description, quantity, unit and data source for each line. A price per kilogram cannot be applied directly to an area or piece count. State any scrap or extra-length allowances according to your method and avoid including them twice.
3. Estimate labour and external services
Distinguish preparation, cutting, fabrication, checks and finishing as required. Apply time allowances and rates consistent with your organisation. Identify subcontracted work and the supplier quotations used. Include transport, lifting and erection where they are in scope: their constraints cannot be inferred from steel weight alone.
4. Establish cost, then price
Add direct items and allocated overheads using a defined rule. Check that no item is already included in a rate or supplier service. The selling price then reflects cost and your commercial decision. A margin percentage on sales differs from a markup on cost; state which basis you are using.
5. Review assumptions and save the version
Date supplier quotations and sensitive assumptions. Review quantities, unit prices, time and services before applying a discount. Retain exclusions and the submitted version. If requirements change, isolate revised lines to explain the cost and price impact rather than silently replacing the first estimate.
Fictional example of a cost breakdown
Illustrative amounts in euros excluding tax. This table is not a typical building price, a rate per square metre or tonne, or a TopSteel price.
| Item | Amount excluding tax |
|---|---|
| Materials | €32,000 |
| Manufacturing | €18,000 |
| Subcontracting | €8,000 |
| Transport and erection | €12,000 |
| Allocated overheads | €10,000 |
| Total forecast cost | €80,000 |
| Agreed selling amount | €100,000 |
| Forecast margin | €20,000 |
These items total €80,000 including allocated overheads. A hypothetical sale of €100,000 leaves €20,000, or 20% of sales. This is a breakdown example; it provides no quantities, standard hours or prices to reuse for your building.
Information to bring to a demonstration
- An anonymised job and the precise offer scope, including exclusions.
- Available quantities, units and assumptions that remain to be confirmed.
- Material and service prices, plus your company’s time allowances and rates.
- A change to test: quantity, material cost, fabrication time or discount.
Apply this method with TopSteel
TopSteel ERP/MES quoting offers cost item breakdowns, forecast margin calculations and saved versions. The 3D configurator is a separate offer. Check imports, units and required exchanges using your own data before defining your estimating workflow.
Frequently asked questions
Can a price per square metre be used on its own?
A ratio can be an internal reference when its scope is known. It does not replace a breakdown for a job with specific framing, envelope, services and erection constraints.
Which cost items should be included?
Depending on scope: materials and components, fabrication, subcontracting, protection, checks, transport and erection, then allocated overheads. Review inclusions to prevent omissions and duplicate costs.
Does an estimate validate the building structure?
No. A commercial estimate is not structural design or technical approval. Quantities and structural assumptions need to be checked within the project.
Sources and definitions
These definitions complement the method proposed by TopSteel. These organisations do not validate the software or the example amounts.