How profile and effective cover affect T18 and T35 sheet prices

The total area results from the external width of the sheet and its length. The effective cover area takes into account the part hidden under the adjacent sheet. If one offer quotes the price for the first type and another for the second, the lower figure does not necessarily mean a cheaper purchase. First bring both offers to the same usable area.

The roof layout may require cut-offs and additional longitudinal overlaps. For this reason the area of the purchased sheets usually does not match the geometric roof area exactly. A schedule of lengths and the number of runs is needed. The product of the roof area and the lowest advertised price alone omits some of the costs.

In the price list effective from 28 October 2026, variant T18 with 0.50 mm steel and 25 µm polyester costs €8.41 net per square metre of effective coverage. The price list gives €10.34 gross for it, at a VAT rate of 23%. This is a specific catalogue variant, cited to show the comparison rules. It is not a sales offer for this page nor an average for the whole market.

In the same listing, for the comparable T35, €9.20 net and €11.31 gross per square metre of effective coverage are given. The difference is €0.97 gross per square metre of coverage. However, this does not determine the price of the whole roof. The variants have different profiles, and the project may require different supports and fixings. Discounts, delivery and accessories are settled separately.

Thicker steel means more material, but also different usage possibilities for a given profile. The choice of thickness should follow from the requirements, not from a wish to reduce a single line item in the cost estimate. In the enquiry, state the nominal thickness of the steel core. Do not replace it with a general statement that the sheet is to be strong or standard.

The metallic and organic coating perform different protective functions. The variants differ in resistance to environmental conditions, radiation and damage. A matt finish alone does not automatically mean higher durability. Compare the description of the specific protection and the warranty conditions. The additional cost of a coating makes sense when it matches the conditions in which the roof will operate.

A higher profile may provide greater rigidity, but the result depends on the entire geometry and the sheet thickness. The support spacing must be checked in the tables for the specific product and loads. Do not assume that choosing T35 will allow every second batten to be omitted. The saving on the structure can only be assessed by the person responsible for the design.

On a small canopy, T18 may meet the requirements with proper support. On another structure, T35 or a structural profile with a greater height will be needed. So compare the cost of the solution that can actually be used. A cheaper sheet brings no benefit if it requires later changes to the structure or does not suit the roof conditions.

Check the price of flashings, screws, seals and any anti-condensation layer. Add transport, unloading and requirements concerning sheet lengths. Some orders have a minimum value or additional logistics charges. It is worth establishing these before comparing discounts, especially for a small quantity of material.

Ask about the production date and the validity of the offer. A list price with a specified date does not guarantee the price in a few months. If you order material in stages, check whether there may be shade differences between batches. Also agree what happens in the event of a measuring error. Sheets made to measure require particularly careful approval of the schedule.

Provide the roof slope drawing, the building location, the intended profile and the full specification. Ask for the total and usable area to be itemised. State the colour, thickness, coating and required date. Add the list of accessories and the delivery method. This way, sellers will quote for a similar scope instead of guessing your expectations.

Before purchase, check the final gross amount and the material documentation. Keep the cutting plan, storage conditions and installation instructions separately. A well-described offer also helps the installer, who knows which sheet they will receive. The most useful question is therefore not only how much T18 or T35 costs, but how much a complete, correctly selected set costs.