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OVER JOIST
APPLICATIONS

Insulating over the joist requires an additional breathable membrane to reduce condensation and water damage. With SuperFOIL’s external solution in your build-up, you get a W1 watertight finish, high levels of moisture protection, improved space optimisation, and the ability to install up to twice as fast compared to traditional insulation types.

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Application Instructions

Apply SuperFOIL directly from the roll horizontally on the internal joist face, starting at the external wall. Staple the roll’s start onto your joist, maintaining tension while stapling at 50mm-100mm intervals with the correct size staples.

After completing a length, ensure a minimum 50mm overlap for the next layer and securely fix by stapling at the joints. Seal joints, tears, and cuts with SuperFOIL 100mm tape, paying special attention to any penetrations through the insulation for an air-tight finish.

Complete the installation by fixing counter battens horizontally on top of the insulation (maximum 600mm centres) to provide adequate air space. Attach your external finish to battens, following the manufacturer’s guidelines.

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

For a more comprehensive guide to properly installing SuperFOIL products in a Flat Roof Over Joist application, we’d encourage you to download our complete installation guide, for free, by clicking the button below.

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Best Products for External Application

SuperFOIL SF19+

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2.53 R Value
When used in a roof

SuperFOIL SF40

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3.47 R Value
When used in a roof

SuperFOIL SF60

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4.48 R Value
When used in a roof

Choose Your Solution

Use the charts below to find the ideal solution for your project

SELECT VARIABLE

THERMAL PERFORMANCE
PRODUCT DIMENSIONS
ESSENTIAL CHARACTERISTICS
PRODUCT COMPOSITION
Specification SF19+ SF40 SF60
Core performance 1.63 R Value 2.57 R Value 3.58 R Value
Roof Performance* 2.53 R Value 3.47 R Value 4.48 R Value
Wall Performance* 2.96 R Value 3.90 R Value 4.91 R Value
Floor Performance* 4.29 R Value 5.23 R Value 6.24 R Value
Emittance 0.05 0.05 0.05

*Core value + 2 air spaces / EN 16012

Specification SF19+ SF40 SF60
Thickness (Nominal) 45mm 65mm 100mm
Length 10m 10m 8m
Width 1.2m/1.5m 1.5m 1.5m
Coverage 12m²/15m² 15m² 12m²
Weight 10kg/13kg 15kg 18kg
Specification SF19+ SF40 SF60
Reaction To Fire (Euroclass) Class F Class E Class E
Water Vapour Resistance 2050 MNs/g 2,500 MNs/g 2,500 MNs/g
Resistance To Water Penetration W1 W1 W1
Tensile Properties (Length) 606/580N/50mm 698/509N/50mm 698/509N/50mm
Tensile Properties (Width) 514/526N/50mm 595/432N/50mm 595/432N/50mm
Resistance to Tearing (Length) 275N 685N 685N
Resistance to Tearing (Width) 305N 585N 585N
Elongation (Length) 24% 22 / 24% 22 / 24%
Elongation (Width) 23% 19 / 26% 19 / 26%
Flexibility at Low Temp. -40°C -40°C -40°C
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

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