Extending an existing production hall presents a contractor with a challenge that simply doesn't arise when building from scratch: new panels must match the existing facade in colour, geometry, and system compatibility. Without a proper diagnosis upfront, the result is a visible mismatch between the old and new sections — one that is extremely difficult to correct after the fact. Below, we describe how we identify the existing system, select the right panels, and avoid costly ordering mistakes.
Diagnosing the Existing Facade — The Starting Point for Every Extension
As-built documentation for halls older than 10 years is frequently incomplete, out of date, or lost following a change of ownership. In these cases, we cannot rely on paperwork alone — we begin with a physical site inspection and on-site measurements.
An inspection of a typical hall with a footprint of 2,000–5,000 m² takes 4–8 working hours. Add to that 2–3 days for preparing the report and dispatching samples to the manufacturer for colour verification.
What We Check During the Inspection
- Panel thickness — measured with callipers at the edge or ultrasonically in the field — standard values: 80, 100, 120, 150, or 200 mm
- Insulation type: PIR (yellowish/cream foam), PUR (brownish foam), or mineral wool (grey, fibrous)
- Outer skin profile: horizontal micro-rib, trapezoidal, or flat
- Jointing system: concealed lock (overlock), exposed fasteners, or cover strip
- RAL colour and sheen: matt, satin, or gloss — photographed under overcast sky conditions (D65)
- Manufacturer markings on the inner skin: series number and production date
Insulation type is identified visually after drilling a small core sample in an inconspicuous location — for example, behind the base trim or behind a downpipe. PIR has a characteristic yellow or cream foam with fine cells; mineral wool is immediately recognisable by its fibrous structure and grey colour.
Manufacturer Identification and System Compatibility
Europe's leading sandwich panel manufacturers — Kingspan, Isopan, Ruukki (Metecno), ArcelorMittal Arval, and Hoesch — each use their own proprietary lock geometry and profile. Systems are not interchangeable between manufacturers. Installing panels from two different systems in the same facade plane is technically inadmissible and voids the warranty on both sides.
We look for manufacturer markings on the inner skin: Kingspan prints the series and production date at regular intervals along the panel; Ruukki embosses its mark into the profile rib. If the markings are illegible or damaged, we send a skin sample for paint analysis to an authorised distributor — Kingspan and Isopan offer this verification within 5–7 working days for 80–150 EUR per sample.
Non-negotiable rule: confusing a Kingspan KS1000 AWP with a KS1000 RW means a difference in lock geometry that prevents correct seating in the existing fasteners — series identification before placing an order is mandatory, not optional.
A particularly challenging situation arises with systems manufactured before 2000: Hoesch Isorock, older BEMO series, and Corus. For these systems, replicating the lock geometry is often impossible. The solution is either to use cover strips at the expansion zone, or to replace the entire wall section with a new, unified system while maintaining insulation continuity.
RAL Colour Matching — Fading and Tolerances
Colour is the hardest element to match when extending an older building. Skins with a standard polyester coating (PE 25 µm) lose saturation at a rate of 2–4 ΔE units per year on a south-facing elevation. After 10 years of service, the facade can deviate from the original RAL colour by as much as 30–40 ΔE units — a difference clearly visible to the naked eye from 15 metres away.
The RAL number is a starting point, not a ready-made solution. When ordering, we request a physical colour sample from the manufacturer and compare it against the existing facade under diffuse light (D65 standard). If the difference exceeds 5 ΔE units, repainting the existing facade after completing the new section is unavoidable.
| Coating system | Fading (ΔE/year) | Colour warranty | Surcharge (EUR/m²) |
|---|---|---|---|
| Polyester PE 25 µm | 2–4 | 10 years | 0 (base) |
| Polyester HDP 35 µm | 1–2 | 15 years | +2–4 |
| PVDF (Hyper / Granite) | <0.5 | 25 years | +8–12 |
The cost of repainting an entire facade with polyurethane paint is 8–15 EUR/m² net, depending on the substrate condition and access. For a 3,000 m² elevation, that is 24,000–45,000 EUR — less than the cost of a 6-week project delay while waiting for custom-colour panels matched by a paint manufacturer.
Thermal and Fire Performance Requirements for Production Halls
New panels must comply with the current energy regulations of the country of installation. For production hall walls, the U-value requirements are: Germany (GEG) U ≤ 0.28 W/m²K, Netherlands (BENG) U ≤ 0.25 W/m²K, Belgium (EPB) U ≤ 0.24 W/m²K, Austria (OIB-RL 6) U ≤ 0.25 W/m²K. A 120 mm PIR panel with λ = 0.022 W/mK achieves U ≈ 0.22 W/m²K, meeting all four requirements with margin to spare.
Fire resistance is critical for halls with fire compartments exceeding 2,500 m². The minimum required reaction-to-fire classification is B-s1,d0 per EN 13501-1. For fire-separating walls, REI 60 or REI 120 is required — and this is where PIR panels fall short, regardless of their favourable U-value. For these applications, we specify only mineral wool core panels, such as Kingspan KS1000 FF or Ruukki Fire.
| Insulation core | λ (W/mK) | U at 120 mm (W/m²K) | Fire class (EN 13501-1) | Panel price (EUR/m²) |
|---|---|---|---|---|
| PIR (polyisocyanurate) | 0.022 | 0.22 | B-s1,d0 | 28–38 |
| PUR (polyurethane) | 0.025 | 0.25 | B-s2,d0 / C | 24–32 |
| Mineral wool | 0.040 | 0.36 (180 mm → 0.25) | A2-s1,d0 / REI 60–120 | 38–55 |
With mineral wool, achieving U = 0.25 W/m²K requires a thickness of 180 mm — a significant difference when matching an existing 120 mm wall. All panels used in European markets must carry a Declaration of Performance (DoP) compliant with EN 14509 and CE marking. In Germany, high-bay warehouses are additionally subject to DGUV Regulation 108-003 — the manufacturer must supply load-bearing capacity values in accordance with DIN 18516.
Project Schedule and Extension Costs
An extension with system matching requires a longer lead time than new construction. The critical variable is the manufacturer's production lead time — 2–4 weeks for a standard RAL colour from stock, and 6–10 weeks for a non-standard colour or special geometry. A delayed order translates directly into site downtime costs and the risk of contractual penalties.
- Site inspection and documentation: 2–3 working days
- Manufacturer identification, ordering a colour sample and colour verification: 5–10 days
- Placing the panel order and confirming series compatibility: 1 day
- Manufacturer production — standard RAL colour: 14–28 days
- Manufacturer production — non-standard colour or PVDF coating: 42–70 days
- Installation of 1,000 m² of facade by a team of 4–6 installers: 5–10 working days
Wall facade installation costs run at 18–28 EUR/m² net in Germany and 20–30 EUR/m² in the Netherlands. The lower end applies to straightforward walls with no openings; the upper end covers facades with corners, multiple openings, and complex flashings. Work above 8 metres using a scissor lift or scaffolding adds 3–5 EUR/m². The budget should also include laboratory colour verification at 150–400 EUR per sample, plus any building inspection with a sealant protocol.
Key takeaways
- Before ordering, carry out a physical facade inspection and unambiguously identify the manufacturer, series, and jointing system — project documentation frequently does not exist or is outdated following a change of building ownership.
- RAL colour matching is not just about a number: order a physical sample and compare it against the existing facade under D65 conditions — fading after 10 years can exceed 30 ΔE units, and the difference is visible to the naked eye.
- For fire compartments exceeding 2,500 m² and fire-separating walls, specify only mineral wool panels (A2-s1,d0, REI 60+) — PIR and PUR panels, despite their lower U-value, do not meet the fire resistance requirements for compartment walls.
- Plan your schedule to allow for a 6–10 week lead time on non-standard colour panels — a last-minute order is a guaranteed site standstill and an uncomfortable conversation with the client.