SuperFOIL products applied on pitched roof over rafters


Insulating over the rafters means it’s essential to use a build-up that won’t pose a condensation risk. SuperFOIL’s external solutions are W1 watertight and ensures high levels of moisture protection, breathable properties, better space optimisation, and the ability to install up to twice as fast compared to traditional insulation types.


If you are installing SuperFOIL SF19BB or SuperFOIL SF40BB (breathable) with tile battens directly on top, you need to drape the material into the rafters for drainage, similar to a breathable membrane. To ensure an adequate drape, SuperFOIL SF19BB requires a minimum cavity of 60mm, while SuperFOIL SF40BB needs a minimum of 90mm. This space should be sufficient to accommodate the material and allow enough room for drainage.

SuperFOIL’s flexibility extends to its application; you can use it on its own, in single/duet configurations, or in combination with traditional insulation types like mineral wool or PIR boards.

All SuperFOIL products needs be stored indoors until used and should be covered within 48 hours after fitting.

Counter Battened

To install SuperFOIL insulation, start by applying it horizontally on top of the rafters, securing the beginning with staples and rolling it out ensuring the material is kept taut to prevent the product from draping. Staple through SuperFOIL into the rafter at approximately 50mm-100mm intervals.

Cut and fasten each length, ensuring a 100mm taped overlap for successive layers. At the roof edges, fold back the external breather membrane, trim the internal insulation layers, fold the membrane over, and staple for a watertight finish.

After installation, check and seal all overlaps, then attach the correct size battens(to provide adequate air space) in line with the roof joists, before attaching your tile batten in line with the manufacturer’s guidelines.

Non – Counter Battened

Apply SuperFOIL by rolling it horizontally on top of the rafters, starting at the bottom. Staple the beginning in place onto the rafter and continue rolling the product across the rafters. Allow SuperFOIL to drape into the rafter void, creating a 10mm gap between the insulation and tile batten to let the water that accumulates or penetrates the tiles to run off. Staple through the SuperFOIL into the rafters at approximately 50mm-100mm intervals using the correct size staples.

Once you have finished a length, cut it to the correct size and fasten it into place before continuing to the next layer. Place the built-in 100mm taped overlap over the previous layer and continue with the installation using the same method. After installation, check and seal all overlaps, and complete the process by attaching tile battens following manufacturers’ guidelines.

Best Products for External Application

Choose your Solution

Use the charts below to find the ideal combination of insulations for your project

Construction Thickness R-Value
External Surface 0.040
Tiles / Slates 10mm
Batten Cavity 25mm
SuperFOIL 1-75mm See Table
Rafter Cavity 25-63mm 0.476
Additional Insulation See Table
Rafter / Batten Cavity 25mm 0.184
Plasterboard 12.5mm 0.066
Internal Surface 0.1

Technical Information

Technical Information


Core performance 1.454 R Value 2.92 R Value
Roof Performance* 2.22 R Value 3.67 R Value
Wall Performance* 2.53 R Value 3.98 R Value
Emittance 0.19 / 0.03 0.19 / 0.03

*Core value + 2 air spaces / EN 16012

Thickness 40mm 75mm
Length 10m 10m
Width 1.2/1.5m 1.5m
Coverage 12/15m2 15m2
Weight 8/10kg 20kg

*Core value + 2 air spaces / EN 16012

Reaction To Fire (Euroclass) Class E (Behind Plasterboard) Class E (Behind Plasterboard)

*Core value + 2 air spaces / EN 16012

Water Vapour Resistance 0.115MNs/g 0.115MNs/g
Resistance To Water Penetration W1 W1
Tensile Properties (Length) 238 / 227 N/50mm 238 / 227 N/50mm
Tensile Properties (Width) 111 / 100 N/50mm 111 / 100 N/50mm
Resistance to Tearing (Length) 179N 179N
Resistance to Tearing (Width) 179N 179N
Elongation (Length) 61 / 57% 61 / 57%
Elongation (Width) 92 / 87% 92 / 87%
Flexibility at Low Temp. -40°C -40°C

*Core value + 2 air spaces / EN 16012

Reflective Coated Breather Membrane 1 1
Perforated Aluminium Coated Reflective Foil PET 3 8
Perforated Reinforced Heavy Outer Reflective Foil 1 1
Loft Quilt 80g/sqm Layers 4 9
Total Layers 9 19

*Core value + 2 air spaces / EN 16012

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