Roof Sandwich Panels

What is Roof sandwich panel?

A roof sandwich panel is a composite: two steel skins and a rigid insulating core act together, the outer skin taking compression, the inner tension and the core the shear, so that a 50 mm panel with 0.5 mm skins spans 3 m under snow that would collapse a bare sheet. The roof version differs from the wall panel in three details. The outer skin is a 5-rib trapezoidal profile (ribs about 40 mm high at 250 mm centres) — stiffer against snow and foot traffic, and a drainage channel that carries the water of a long slope at pitches down to 5 %. The side joint overlaps: one panel\'s edge rib lies over the next panel\'s core, with a factory-applied or site-applied butyl seal under the lap, so the joint sheds water instead of relying on a tongue-and-groove. And the fixing goes through the rib crest into the purlin with a long self-drilling screw and a saddle washer, every rib at the eaves and every second rib elsewhere. Cores: PIR (polyisocyanurate, λ ≈ 0.022 W/mK, B-s1,d0 or B-s2,d0) is the standard — best insulation per millimetre and self-extinguishing; PUR is the older, cheaper polyurethane with slightly worse fire behaviour; rockwool (λ ≈ 0.040, A2-s1,d0, 100–120 kg/m³) where the fire code demands a non-combustible roof. Thickness sets the U-value: 40 mm PIR ≈ 0.52 W/m²K for unheated sheds, 50 mm ≈ 0.42 the market standard, 80–100 mm (0.27–0.21) for heated halls and 120–150 mm for the EU energy codes. Skins are PPGI 0.50 outer / 0.40 inner as standard (0.60 for long spans and foot traffic), in RAL 9002 outside and 9002 or 9010 inside. Panels are cut to any length to 14 m so a whole slope is one piece, and we supply the ridge caps, eaves and verge flashings, foam closures, screws and butyl in the same colour batch.

Grades, standards and tolerances

Thickness, U-value and span

Roof panel details

Skins, coatings and colours

Lengths and stock

PIR roof panels 40, 50 and 80 mm in 9002/9002 with 0.50/0.40 skins are produced continuously and shipped in 5–10 working days at any length to 14 m; 100–150 mm, rockwool cores, other colours and skylight panels in 2–3 weeks. Ridge caps, flashings, closures, end-lap kits, screws and butyl tape are made and packed with the panels.

Fixing, sealing and installation

Lay from the eaves upward and against the prevailing wind; fix through the rib crests with 5.5 mm self-drilling screws long enough for core + purlin (e.g. 5.5 × 115 for 50 mm on a steel purlin) with 19 mm EPDM saddle washers — every rib at eaves, ridge and end laps, every second rib elsewhere, minimum 50 mm from the panel end; press the side lap onto its butyl seal and stitch at 500 mm with 4.8 mm screws. End laps (if any) 200–300 mm with the core cut back and double butyl. Cut with a cold saw or fine-tooth circular saw; never a grinder. Lift with vacuum lifters or clamps; walk on the rib lines over purlins; keep the film on until fixed and remove within 3 months.

Where it is used

• Roofs of warehouses, factories and logistics halls
• Commercial and retail buildings
• Agricultural buildings and stables
• Cold-store and food-plant roofs (with matching wall panels)
• Prefab and modular buildings, camps
• Re-roofing over existing purlins

Roof panel vs wall panel vs built-up roof

The wall sandwich panel has flat or micro-ribbed faces and a tongue-and-groove joint — not for roofs. A built-up roof (T38 sheet + insulation + T27 liner) costs about the same in material, more in labour, and allows thicker insulation; the panel wins on speed. Core choice: PIR, PUR, rockwool — each has its page. The sandwich panel overview covers the whole range.

Price

Roof panels are priced per m² by thickness, core and skins on the panel list; PIR 50 mm with 0.50/0.40 skins is the reference, rockwool about 20–30 % more, and every 10 mm of PIR adds a few percent. The bands below are the month\'s indicative FOB Istanbul ranges for 50 and 100 mm PIR; accessories per metre and per hundred.

Bands from our weekly export list (September 2026), FOB Istanbul, full-container quantities, excluding freight and certificates. Firm price per project on RFQ within one working day.

Export and packing

Roof panels are stacked 8–12 per pack (rib-to-rib with foam spacers), PE film on both skins, strapped on timber bearers with edge protection and PE-wrapped, each pack labelled with type, core, thickness, colours, length and count. Volume fills the container before weight: a 40' HC takes about 400–550 m² of 50 mm roof panels, less for thicker; 12–14 m panels go on flat-racks or by covered truck to Iraq, the Balkans and the Caucasus. Accessories are packed by colour in the same load. HS 7308.90 / 9406.

Certificates

Panels ship with the CE declaration of performance under EN 14509 (thermal transmittance, load-span, fire class, core density), the skin coil EN 10204 3.1 certificates, the EN 13501-1 fire classification report for the core and the project span calculation on request.

How to order

Specify core (PIR / PUR / rockwool), thickness, outer and inner skin gauge and RAL colours, panel lengths and quantities (or the roof plan and purlin spacing for a cutting list and span check), slope, accessories (ridge, flashings, closures, end-lap kits, screws, skylights) and destination.

Standards

• EN 14509 — self-supporting double-skin metal-faced insulating panels
• EN 13501-1 fire classification; EN 13165 (PIR/PUR), EN 13162 (mineral wool), EN 13163 (EPS) cores
• EN 10169 / EN 10346 skin steel
• EN 10204 3.1

Grades

Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: DX51D · S250GD · S280GD