The load capacity and the external durability of a sandwich panel come largely from the steel. Where that steel is sourced decides something else: the lead time and the continuity of supply. The two are separate subjects and are asked about separately when a quotation is assessed.

What does the source of the steel change?

Lead time. With domestic supply, the coil enters the production plan sooner. After the coating and the colour are chosen, the delivery schedule of a panel order depends largely on when the coil reaches the line.

Continuity of supply. On long projects, second and third batches follow. A coil from the same source differs from a single-batch job in colour and surface consistency: two panels of different shade standing side by side on an elevation usually come from a batch difference.

Currency and price movement. With imported coil the price moves with the exchange rate and the freight. On projects with long delivery schedules this is an item that has to be fixed.

Four figures that set performance

Whatever the source of the steel, four numbers decide how the panel behaves, and all four are written on the quotation.

  1. Steel thickness. Inner and outer sheets separately. Most of the load capacity comes from here; if only one number is written, ask which face it refers to.
  2. Coating class. Polyester is standard; PVDF or plastisol is chosen on the coast and in aggressive atmospheres. The coating decides the interval between repainting.
  3. Colour. Given to the RAL chart. Custom colours require separate production planning and lengthen the lead time. The chart is in the Library section.
  4. Traceability. Which batch the coil came from and which order the panel belongs to are recorded. That is what there is to talk about when something goes wrong.

What domestic production means on the project side

A panel made in Türkiye brings an advantage separate from the source of the steel: it is cut to the project. When panels are not bought in standard lengths and cut on site, waste falls, and waste is money.

In the same way, a short delivery interval means that on a project with revisions, the second order arrives within an acceptable time. Getting the quantities right is the precondition: the panel area calculator gives the count and the total area surface by surface.

Three questions to ask on a quotation

  • What is the steel thickness on the inner and outer faces, in mm
  • What is the coating class, and which environment was it recommended for
  • How will colour consistency be maintained when the second batch of the same project arrives

When all three are answered in writing, the source of supply stops being a risk item. The certificates and declarations of performance are in the Library section.