What do T18 and T35 trapezoidal steel sheets cost and how do you compare quotes?

In the price list dated 28 October 2026, the T18 roof variant with a thickness of 0.50 mm and a standard polyester coating had a price of €8.41 net and €10.34 gross per square metre of effective cover. In the same list, T35 in a comparable finish cost €9.20 net and €11.31 gross per square metre of effective cover. The prices related to specific profiles and did not cover a complete roof.

The second price list, checked on 1 November 2026, stated €8.41 net per square metre of cover for T18 and €9.04 net for a variant from the T35 group. One should not derive a single rate for the whole market from these examples. Geometry, sales conditions and product scope differ. Before ordering, a current offer is needed for the specified quantity, lengths and finish.

The overall width covers the part of the sheet that will lie in the overlap. The effective width describes the actual increase in coverage when the next sheet is added. If the steel sheet has an overall width of 1.173 m and a cover width of 1.128 m, these two square metres do not mean the same in the calculation. The value per overall metre must be converted.

The catalogue example illustrates this difference well. The price of €8.09 net per square metre of total area corresponds to €8.41 net per square metre of effective cover for the specified T18. In both cases it is the same material. An offer with a lower figure is not necessarily cheaper if it uses a different basis. To compare, use the same unit of coverage and compare either net prices or VAT-inclusive prices throughout.

Greater thickness means a greater quantity of steel, and a different coating can change the cost of protection. In the price list from the end of October, the T35 variant with gloss polyester at a thickness of 0.70 mm cost €14.03 net per square metre of effective cover. However, this is not a substitute chosen solely according to budget. The thickness must match the support and load requirements.

Differences between coatings must be assessed according to their application. Matt does not automatically mean the same level of protection as another matt. It is worth comparing the protection system, parameters and warranty conditions. A cheaper finish may be sufficient in some conditions and unsuitable in others. The price should be considered among products permissible for the given roof.

The roof slope area is the starting point. Overlaps resulting from the profile and any longitudinal joints, as well as pieces cut off at the edges, are added to the order. An arbitrary percentage should not be added and treated as an exact result. A cutting plan with the number of sheets and their lengths is needed.

With a rectangular roof slope, the number of strips can easily be checked against the coverage width. The last sheet usually requires adjustment. With roof valleys and triangular slopes, the layout is more complex. The cut-off fragment cannot always be transferred to the other side, because the profile orientation and overlap matter. The price of the material used and the material purchased may therefore differ.

Edge flashings, ridge, fasteners and project-specific components are required. Depending on the roof, additional layers under the covering and a condensate solution are added. An anti-condensation mat, if suitable for the application, may be a separate surcharge. It should not be treated as a substitute for thermal insulation or for all roof layers above a residential room.

Check the cost of delivery, unloading and any logistical minimum. A small order may have different economics than a delivery for an entire building. The labour quote should cover a specific scope, including flashings and substrate preparation. Simply comparing the rate per metre of sheet with the installation price does not yet give the cost of the completed covering.

Specify the profile, nominal thickness, coating type, colour and decorative side. Attach a sketch of the roof slope and the required lengths, if these have been correctly determined. Ask for the price per effective metre and the total for the whole set. Separate material from transport and accessories. This makes it easier to identify whether the difference stems from parameters or from the scope of supply.

Treat list prices as a reference point with a specific date. They do not determine the transaction price or colour availability. Before purchase, confirm the validity of the offer and the documentation. T18 will not be a better purchase just because it has a lower rate, if the project requires a different profile. Savings make sense once the technical requirements of the roof are met. Keep the calculation date and the validity of the quote. For a purchase deferred in time, it is worth renewing the offer rather than basing the budget solely on a previously read price list.