Insulated Sheets

Why roofs get insulated

A bare metal roof takes on heat all day and gives it back into the building. Under an uninsulated shed roof in an Indian summer the working level can sit several degrees above outside shade temperature, which affects staff, stored goods and the running cost of anything doing cooling. Insulated roofing puts a barrier between the sheet and the space below so less of that heat gets through, and so that rain noise and machine noise do not travel as freely.

The same layer works in reverse for cold storage, where the job is keeping cold air in rather than heat out.

The options we supply

Double skin insulated systems use two metal sheets with insulation between them. The outer sheet takes the weather, the inner sheet gives a finished ceiling, and the core does the thermal work. This is the usual specification where the underside of the roof is visible and needs to look finished, such as showrooms, food units and clean areas.

EPS roof and wall panels are factory-made sandwich panels with an expanded polystyrene core. They arrive as a single unit, so erection is quicker than building up a double skin on site, and they suit partition walls and cold rooms as well as roofing.

Rockwool and glasswool are mineral fibre blankets laid under the sheet. Rockwool holds its shape at higher temperatures and is the choice where fire behaviour is being considered. Glasswool is lighter and generally cheaper for the same thickness. Both also cut noise, which is why they show up in auditoriums and workshops as often as in cold stores.

Polynium bubble sheet is a reflective foil bonded to an air bubble layer. It is thin, quick to fix and works mainly by reflecting radiant heat rather than resisting conducted heat. It is the practical retrofit for an existing roof where there is no room to build up thickness.

XLPE insulated sheet uses a closed cell cross linked polyethylene foam. The closed cell structure means it does not soak up moisture, so it holds its performance in humid conditions better than an open fibre would.

Choosing between them

Three questions usually settle it. Is this a new roof or an existing one? A new build can take a double skin or sandwich panel; a retrofit is easier with bubble or XLPE laid under the existing sheet.

Is the underside visible? If people will look up at it, a double skin or panel gives a finished surface. A blanket needs a liner sheet or wire mesh to hold it and to look reasonable.

Is the problem heat, cold or noise? Radiant barriers like foil work well against roof heat gain. Cold storage needs real thickness in the core. Noise needs mass or fibre rather than reflectivity.

Thickness and where it matters

Insulation is sold by thickness and density, and both change the result. Doubling thickness does not double performance, so there is a point past which more material stops paying for itself in an ordinary shed. Cold storage is the exception, because the temperature difference is far larger and runs continuously.

Whatever the material, the weak points are the same: gaps at laps and edges, and compression where a fixing pulls the material tight. Insulation that is squashed flat at every screw line is doing much less work than the specification suggests.

What to tell us

Send the roof area, whether it is new or existing, what the building is used for, and whether the underside will be seen. If it is cold storage, the target internal temperature changes the answer completely. We will come back with the options that actually fit rather than the thickest thing on the list.