U-VALUE CALCULATOR
UNDER RAFTER PITCHED ROOF - SUPERFOIL

UNDER RAFTERS
(INTERNAL)

While insulating below the rafters, it is essential to keep warm, moist air from moving into the building, and an additional VCL that goes below the insulation is ideal. SuperFOIL’s internal solutions ensure a built-in vapour resistance of 1200MNs/g, better functionality, improved space optimisation, and the ability to install up to twice as fast compared to traditional insulation types.

Application

Apply SuperFOIL directly to the rafters either horizontally or vertically. When applying horizontally, start from the bottom, overlapping layers at each join. For vertical installation, start at the high point of the rafters and roll down.

Maintain tension while stapling the product to the rafters at 150mm intervals. Use recommended staples (refer to chart). After each length, cut to size and continue with a minimum 50mm overlap for the next layer. Securely staple at joint crossings.

At the eaves, trim SuperFOIL around rafters and seal to the wall plate or cavity wall insulation if present. Seal all joints, tears, and cuts with SuperFOIL 100mm tape, especially around penetrations for an airtight finish.

Finish by installing counter battens horizontally (maximum 600mm centres) on top of the insulation to allow adequate air space. Attach your internal finish to battens following the manufacturer’s guidelines.

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.

Best Products for Internal Applications

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
Breather Membrane 1mm
Rafter Cavity 25mm 0.184*
Additional Insulation See Table
Rafter Cavity 38-63mm 0.476
SuperFOIL 40-100mm See table
Batten Cavity 38-63mm 0.476
Plasterboard 12.5mm 0.066
Internal Surface 0.100
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Technical Information

Technical Information

SELECT VARIABLE

THERMAL PERFORMANCE
PRODUCT DIMENSIONS
FIRE PERFORMANCE
ADDITIONAL INFO
PRODUCT COMPOSIITON
SF19+ SF40 SF60
Core performance 1.63 R Value 2.57 R Value 3.58 R Value
Roof Performance* 2.27 R Value 3.47 R Value 4.42 R Value
Wall Performance* 2.73 R Value 3.91 R Value 4.88 R Value
Floor Performance* 4.37 R Value 5.22 R Value 6.53 R Value
Emittance 0.05 0.05 0.05

*Core value + 2 air spaces / EN 16012

SF19+ SF40 SF60
Thickness (Nominal) 45mm 65mm 100mm
Length 10m 10m 8m
Width 1.2m/1.5m 1.5m 1.5m
Coverage 12m²/15m² 15sqm 12m²
Weight 10kg/13kg 15kg 17.75kg

*Core value + 2 air spaces / EN 16012

SF19+ SF40 SF60
Reaction To Fire (Euroclass) Class E Class E Class E

*Core value + 2 air spaces / EN 16012

SF19+ SF40 SF60
Water Vapour Resistance 2,500MNs/g 2,500MNs/g 2,500MNs/g
Resistance To Water Penetration W1 W1 W1
Tensile Properties (Length) 757/ 784 N/50mm 757 N/50mm 757/ 784 N/50mm
Tensile Properties (Width) 726 / 757 N/50mm 726 N/50mm 726 / 757 N/50mm
Resistance to Tearing (Length) 450N 450N 450N
Resistance to Tearing (Width) 491N 491N 491N
Elongation (Length) 15% / 17% 15% / 17% 15% / 17%
Elongation (Width) 14% / 16% 14% / 16% 14% / 16%
Flexibility at Low Temp. -40°C -40°C -40°C

*Core value + 2 air spaces / EN 16012

SF19+ SF40 SF60
Reinforced Heavy Duty Double Foil Laminated Outer Layers 2 2 2
Mesh Reinforced Foil Laminated Outer Layers 0 0 0
Aluminium Coated Reflective Foil PET Layers 4 8 11
Thermo Foam Separation Layers 0 0 0
Loft Quilt 80g/sqm Layers 5 9 12
Total Layers 11 19 25

*Core value + 2 air spaces / EN 16012

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