What affects the price of T18 and T35 trapezoidal sheets?

T18 and T35 have different profile heights and geometries. They may need different amounts of steel for the same cover area. Thickness, protective finish and ordered format also affect the price. A 0.50 mm version should not be compared with 0.70 mm as if the name were the only difference.

The organic coating matters. Gloss polyester, matt polyester and polyurethane may have different properties and warranty conditions. Assess any premium against the service environment. A more expensive coating cannot replace suitable geometry, required load capacity or carefully made joints.

The Polish source’s example catalogue, valid from 28 October 2026, lists 0.50 mm roof-grade T18 with 25 µm polyester at PLN 36.34 net per m² of effective cover. Its stated gross price with 23% VAT is PLN 44.69. This example has 1100 mm cover width and 1142 mm overall width; the quoted amounts are retained as dated source figures.

In the same list, 0.50 mm roof-grade T35 in the same coating group costs PLN 39.73 net and PLN 48.86 gross per m² of effective cover. Its cover width is 1035 mm. These catalogue examples neither establish the price of every sheet carrying that designation nor constitute a budowlanka.org offer.

For that T18 configuration, the 0.60 mm version with 25 µm polyester is PLN 46.72 net, while 0.70 mm is PLN 57.10 net per m² of effective cover. T35 at 0.70 mm is PLN 60.63 net. All figures come from the same dated example and compare specific configurations.

For 0.50 mm T18, changing 25 µm polyester to 35 µm matt polyester raises the example net price from PLN 36.34 to PLN 41.53. A 55 µm polyurethane coating is PLN 57.10 net in that list. Before paying more, check performance and warranty conditions, not just the advertised warranty duration.

Effective area measures coverage after the side lap. Overall area includes the entire sheet, including the part hidden by its neighbour. A lower rate per overall square metre does not prove a cheaper purchase. Ask suppliers for the same unit and a complete sheet schedule.

To convert a price per linear metre, divide it by cover width in metres. For example, PLN 55 per metre of length with 1.10 m cover width equals PLN 50 per effective m². This is arithmetic, not a selling price. Where sheets join along their length, the end-lap area must also be allowed for.

Sheets are not the whole roofing cost. Screws, flashings and suitable seals are needed. Depending on the roof, add underlying layers and support preparation. Calculate waste at hips and valleys separately; not every offcut can be used elsewhere.

Check surcharges for small orders, unusual lengths, transport and unloading. Long sheets may need handling equipment. A collection price is not comparable with delivery to a difficult-access site. Confirm quotation validity and expected lead time as well.

A lower commercial grade can suit some applications, but you need to know the defects, lengths and actual usable area. Scratches, colour differences and distorted joints have different consequences. The label second grade alone does not establish suitability for a weatherproof roof.

For a critical building envelope, check documentation and design compliance. Savings can disappear if missing lengths must be bought or much of the batch rejected. Compare the cost of material actually used, especially with mixed profiles, thicknesses and coatings.

State the application, specified profile, steel thickness and intended coating. Include sheet lengths, quantities and delivery location. If selection is still open, provide a roof drawing and support spacing. These details prevent a quotation for an arbitrarily cheap but unsuitable version.

Finally, compare identical effective roof areas and complete order costs. Better cutting efficiency or transport can outweigh a difference of a few PLN per square metre. Keep three successive totals in the comparison sheet: price converted to effective cover, the cost of usable material after cutting, and the order including accessories and delivery. Each answers a different purchasing question.