Description
Sheeting a workshop, garage or agricultural building the traditional way is three separate operations: fix the liner, lay the insulation, then fix the outer sheet over the top. An insulated composite panel collapses all three into one. The 80mm rigid PIR core is factory-bonded between a ribbed anthracite outer face and a flat steel liner, so a single lift gives you a weathertight roof, the insulation and a finished internal ceiling at the same time.
These panels are supplied in five stock lengths from 3.075m to 7.075m, each with a 1000mm cover width and a 75mm cutback at the eaves end. At 80mm the core gives a U-value of 0.25 W/m²K — the thickness most people settle on for a heated workshop, a garden studio, a stable block or any building where both heat loss and condensation need dealing with properly rather than patched over.
Check your rib spacing before you order
This panel has a 33mm rib at 250mm centres — four ribs across the 1000mm cover width. Several other composite roof panels on the UK market use a three-rib profile at 333mm centres. The two are not interchangeable: a 250mm-pitch panel will not line up or lap correctly against a 333mm-pitch roof. If you are extending, repairing or matching into an existing composite roof, measure the rib centres on what is already there before ordering. For a complete new roof this makes no difference — just order the whole roof in one profile.
Where these panels work well
- Workshops, garages and home studios where the roof needs to be warm and finished inside without a separate ceiling
- Agricultural and equestrian buildings — stables, feed stores, machinery sheds
- Commercial units, storage buildings and light industrial roofs
- Re-roofing an existing single-skin metal building that suffers from condensation and heat loss
Technical specification
| Insulation core | Rigid PIR, approximately 40 kg/m³ |
|---|---|
| Core thickness | 80mm |
| U-value | 0.25 W/m²K |
| Cover width | 1000mm |
| Outer face | 0.5mm profiled steel, anthracite polyester paint finish |
| Liner face | 0.5mm flat steel |
| Rib height | 33mm |
| Rib spacing | 250mm centres (4 ribs per panel width) |
| Eaves cutback | 75mm |
| Minimum roof pitch | 4° after deflection |
| Stock lengths | 3.075m, 4.075m, 5.075m, 6.075m, 7.075m |
| Sold as | Individual panels — order the quantity you need |
Frequently asked questions
How many panels do I need?
Divide the width of your roof slope by 1.0m — the cover width — and round up. Then pick the length that spans from ridge to eaves in one piece if you can; a single unbroken panel is always a better roof than two panels with an end lap in the middle. Order one spare if the roof is an awkward shape.
What is the 75mm cutback for?
At one end of the panel the insulation core and the steel liner are trimmed back 75mm, leaving the outer sheet projecting on its own. That projecting lip is what oversails the gutter at the eaves, so rainwater discharges into the gutter rather than tracking back into the panel end. Fit the cutback end at the eaves, not at the ridge.
Can I lay these at a lower pitch than 4°?
No. 4° is the minimum after deflection, which means the roof needs to still be at 4° once the panels have taken up their loaded position under their own weight, snow and any foot traffic. On long spans that usually means designing to a steeper nominal pitch so you still have 4° left when it settles. Below that, water sits on the laps instead of running off them.
Do I still need insulation and a vapour control layer underneath?
No — the panel is the entire roof build-up in one component, and that is the point of it. What still needs attention is the junctions: eaves, ridge, verges and any penetrations need correctly detailed flashings and fillers, because that is where air and moisture will find their way in if the detailing is rushed.
How are the panels fixed down?
They are through-fixed into purlins with composite panel fixings long enough to pass through the full 80mm depth and bite into the steel or timber below, with sealing washers. Fixings are not supplied with the panels — the correct length depends on your purlin type, so order them once you know what you are fixing into.
What else you will need
Panels arriving on a building that also needs plain sheeting, drainage or edge protection pair naturally with the rest of our industrial roofing range:
- Box Profile Steel Roofing Sheets 32/1000 — single-skin sheeting for lean-tos, porches and unheated sections of the same building
- Foil-Faced PIR Insulation Board — for flat roof and warm deck areas where a composite panel is not appropriate
- Aluminium Half Round Gutter System 125mm — to take the discharge at the eaves
- Freestanding Roof Edge Protection Guardrail Kit — non-penetrating edge protection while the roof is being sheeted
Not sure which length suits your span, or whether your existing roof is a 250mm or 333mm rib pitch? Send us the rib measurement and the slope length and we will tell you what fits.
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