SuperFOIL SFUF Underfloor Multifoil Insulation – Ultra-Slim 3-in-1 Floor Solution

SuperFOIL SFUF is a high-performance underfloor multifoil insulation designed specifically for floor applications where minimal build-up depth, vapour control, and ease of installation are required. With a nominal thickness of 6 mm, SFUF delivers insulation, a radiant barrier, and a vapour control layer (VCL) in one ultra-slim, flexible system.

SFUF is suitable for use over concrete floors, over timber floors, under screed, and under underfloor heating (UFH), making it ideal for new builds, retrofits, extensions, and DIY projects.

This is a vapour-closed underfloor insulation with an integrated vapour control layer, designed to improve thermal efficiency and moisture control in floor constructions.

For underfloor systems such as SuperFOIL SFUF, internal comparative assessments indicate that when installed as part of a typical floor construction, the 6 mm system can provide thermal performance broadly comparable to approximately 50 mm of expanded polystyrene (EPS) or 30 mm of extruded polystyrene (XPS) under representative installation conditions. In addition to thermal performance, SFUF can contribute to improved acoustic comfort, helping to reduce impact and airborne sound transmission by up to 22 dB, depending on floor build-up and installation method.

Due to differences in floor construction, screed type, air gap configuration, and overall system design, these comparisons are provided for indicative comparison purposes only. Exact thermal and acoustic performance must always be verified using the certified R-Values of the product and, where required, project-specific assessments.

Product Dimensions & Coverage

• Thickness: 6 mm

• Length: 8 m

• Width: 1.5 m

• Coverage: 12 m² per roll

• Weight: approx. 6 kg

3-in-1 Multifunctional Design

SuperFOIL SFUF combines three essential functions in a single product:

• Thermal insulation for improved floor performance

• Radiant barrier reflecting radiant heat back into the room

• Integrated vapour control layer (VCL)

This integrated design simplifies floor build-ups, reduces the need for additional layers, and supports efficient installation in both standalone and hybrid systems.

Thermal Performance

Despite its ultra-slim profile, SFUF delivers certified thermal performance when installed correctly.

Certified thermal performance:

• Core R-Value: 0.8 m²K/W

• Emittance: 0.9

These values demonstrate SFUF’s effectiveness as a space-saving underfloor insulation, particularly where build-up height is restricted.

What does R-Value mean?

R-Value (m²K/W) measures a material’s resistance to heat flow.
The higher the R-Value, the better the insulation performance.

What does Emittance mean?

Emittance measures how much heat a surface emits (radiates).

A low emittance value (typically around 0.05) means very low heat emission and high reflection of radiant heat, improving overall thermal performance when installed with adjacent air spaces.

This interpretation is aligned with EN 16012 and reflects how reflective multifoil insulation performance is evaluated across EU technical documentation.

Performance vs Traditional Floor Insulation

Traditional floor insulation systems often require significant thickness and multiple layers to manage insulation and vapour control. SuperFOIL SFUF provides a thin, flexible alternative, delivering insulation and vapour control in a single product.

Its slim profile makes SFUF especially suitable for retrofit floors and refurbishment projects where increasing floor height is not possible.

Exact thermal performance depends on the full floor build-up and installation method.

Product Composition & Application Overview

Key Benefits

• Ultra-slim underfloor insulation – only 6 mm thick

• Designed specifically for floor applications

• Can be screeded directly over thanks to built-in protective layer

• Suitable for underfloor heating systems (UFH)

• Replaces insulation, vapour control layer, and radiant barrier

• Easy to install – no specialist tools required

• Lightweight, flexible, and easy to cut to size

• Suitable for new builds, retrofits, and extensions

• Can be used in standalone or hybrid insulation systems

• Made from durable, long-lasting materials

Applications

SuperFOIL SFUF is suitable for use in:

• Over concrete floors

• Over timber floors

• Under screed

• Under underfloor heating (UFH) systems

Installation typically involves cutting to size, sealing joints with tape, and securing to the surface prior to screeding or floor finish installation.

Installation Guidance (Floor & Joist-Based Systems)

The flat roof joist installation principles shown in the guides below are also applicable to underfloor constructions, as both floor and flat roof systems use the same joist-based structural build-up.

Joists are the structural support members (typically timber or steel) that carry floor or roof loads. In underfloor applications, insulation is installed either over or under the joists in a comparable way to flat roof constructions.

Always select the installation guide that best matches your specific floor or structural design.

Fire & Safety Performance

• Reaction to Fire: NPD (No Performance Determined)

• Water penetration: W1

• Flexibility at low temperatures: -40 °C

SFUF – Quality & Certification

• Manufactured under a certified ISO 9001:2015 quality management system

• CE certified to EN 13984:2013 for vapour control performance

• Declaration of Performance (DoP) issued and verified

• Tested to meet current UK and EU building regulations when installed correctly

• Designed, tested, and supported by SuperFOIL technical specialists

• Independently tested and assessed as part of the SuperFOIL insulation range, with notified body verification (KIWA)

Why Choose SuperFOIL SFUF?

SFUF is specified where floor build-up height is critical and where fast, efficient installation is required. Its ability to be screeded directly over, combined with vapour control and radiant performance, makes it a practical solution for residential and light commercial floor projects.

It is particularly valuable in refurbishment and retrofit scenarios where traditional thick insulation systems are impractical.

SFUF Insulation & Recommended Accessories

Summary

SuperFOIL SFUF is a purpose-designed underfloor multifoil insulation that delivers insulation, vapour control, and radiant performance in an ultra-slim format. Easy to install and compatible with screed and underfloor heating systems, it provides a practical, space-saving solution for modern floor constructions.