FINIXPE Acoustic Underlay: FINIXPE vs Combilay
FINIXPE acoustic underlay is a premium 2mm underlay solution designed to enhance acoustic performance, cushioning and moisture protection beneath compatible laminate and floating engineered wood flooring installations.
When installing a floating floor, the surface you walk on is only part of the story. The underlay beneath the flooring contributes to the comfort, support, moisture protection and acoustic performance of the complete flooring system.
For years, traditional products such as Combilay have provided a suitable and cost-effective underlay solution. FINIXPE introduces cross-linked IXPE foam technology with additional acoustic, rebound, thermal and installation characteristics.
Why FINIXPE Acoustic Underlay Matters
FINIXPE acoustic underlay provides a premium foundation beneath compatible floating flooring systems. Whether installing laminate flooring or compatible floating engineered wood flooring , the correct underlay forms an important part of the installation.
Underlay sits between the subfloor and floating flooring. It provides cushioning and can contribute to moisture protection, acoustic comfort and floor stability. Different underlay materials provide different performance characteristics, which is why selecting the appropriate product matters.
Combilay represents FINfloor’s traditional, cost-effective underlay solution. FINIXPE uses Irradiated Cross-Linked Polyethylene technology to provide a more advanced acoustic underlay option with additional listed benefits.
Browse the full FINfloor flooring collection to explore laminate, engineered hardwood and other flooring solutions.
Understanding Combilay Underlay
Combilay has been used for years as a suitable and cost-effective underlay within the flooring industry. It consists of a 2mm thick polyethylene closed-cell foam, commonly known as aerothene, laminated onto a clear 80-micron virgin plastic moisture membrane.
Aerothene is a flexible and durable material that provides slight insulating and cushioning properties. When laminated onto a plastic film, the vapour barrier creates a smooth, moisture-resistant layer suitable beneath compatible laminate flooring.
The Combilay moisture membrane includes a 100mm overlap on one side, which is taped down during installation.
FINfloor’s technical information lists several Combilay benefits including cushioning, moisture and mould resistance, non-absorbent and rot-resistant properties, protection from moisture egress originating from the screed and enhanced floorcovering lifespan.
Combilay is also listed as having minimal thermal properties. Its technical specification records a 45% sound reduction compared with installing flooring with no underlay.
This makes Combilay a practical option where the project calls for a traditional and cost-effective underlay rather than the additional listed performance characteristics available from FINIXPE.
What Is FINIXPE Acoustic Underlay?
FINIXPE acoustic underlay is manufactured using Irradiated Cross-Linked Polyethylene, commonly known as IXPE.
FINfloor’s technical specification describes IXPE as an extra-fine foam manufacturing technology offering advanced moisture protection while also acting as a shock absorber. FINfloor refers to this as Progressive Foam Technology, which contributes to sound suppression and reduction.
The cross-linking process gives IXPE excellent anti-crush properties and very good memory retention. This helps the material retain its form and continue supporting the floorcovering during use.
FINIXPE is 2mm thick and laminated to a clear 80-micron virgin HDPE moisture membrane. The membrane has an overlap on one side and a self-sealing strip on the other for convenient installation.
The FINIXPE technical specification describes the material as non-toxic and odourless and states that it does not contain toxic auxiliary agents in its make-up.
It is also listed as resistant to mould and mildew, non-absorbent, rot resistant, anti-static and anti-allergenic, with resistance to bacteria and dust mites.
Compare FINIXPE and Combilay
Select an underlay below to explore its key construction and technical characteristics.
FINIXPE Acoustic Underlay
Cross-linked IXPE technology combines acoustic properties, cushioning, rebound and an integrated moisture membrane in a 2mm underlay.
Combilay Underlay
Combilay uses 2mm polyethylene closed-cell aerothene laminated to a moisture membrane for cushioning and moisture protection.
FINIXPE Acoustic Underlay Features and Benefits
Moving from standard aerothene to cross-linked IXPE provides a range of additional listed performance characteristics for compatible floating-floor installations.
Sound Absorption
FINIXPE is described as sound absorbent rather than reflective and provides increased acoustic properties and sound absorption.
Excellent Rebound
IXPE provides excellent anti-crush properties and very good memory retention, helping it retain resilient support beneath the floor.
Moisture Protection
The 80-micron virgin HDPE membrane is laminated onto the IXPE underlay and provides additional moisture protection.
Mould & Mildew Resistance
FINIXPE is listed as moisture and mould resistant, non-absorbent and rot resistant.
Increased Thermal Properties
Increased thermal properties and energy-saving benefits are included in FINIXPE’s listed technical characteristics.
Easy Installation
The moisture membrane includes an overlap and self-sealing strip for quick and convenient installation between adjoining sections.
Anti-Static
Anti-static performance is included among the stated benefits of FINIXPE.
Anti-Allergenic
FINIXPE is listed as anti-allergenic with resistance to bacteria and dust mites.
Cushioning
The IXPE foam provides cushioning and shock-absorbing characteristics beneath compatible floating flooring.
Floorcovering Support
Good memory retention and rebound properties are intended to contribute to continued performance beneath the floor.
Non-Absorbent
FINIXPE is listed as non-absorbent and rot resistant, adding to its suitability beneath compatible floating floors.
Integrated Membrane
The HDPE moisture membrane is already laminated to the IXPE underlay, combining cushioning and moisture protection in one product.
FINIXPE Acoustic Underlay Acoustic Performance
The acoustic data is one of the clearest technical distinctions between FINIXPE and traditional Combilay.
FINfloor’s FINIXPE technical specification lists both Sound Transmission Class and Impact Insulation Class information.
FINIXPE technical information lists an STC rating of 66 dB.
The stated FINIXPE STC test result is 69 dB.
FINIXPE technical information lists an Impact Insulation Class rating of 72 dB.
The stated FINIXPE IIC test result is also 72 dB.
FINIXPE Acoustic Underlay vs Combilay
Both underlays are 2mm thick and incorporate a moisture membrane, but their material technology and listed performance characteristics differ.
| Feature | Combilay | FINIXPE |
|---|---|---|
| Material | Polyethylene closed-cell foam / Aerothene | Irradiated Cross-Linked Polyethylene |
| Thickness | 2mm | 2mm |
| Moisture Barrier | 80-micron HDPE | 80-micron virgin HDPE |
| Overlap | 100mm; requires taping | 100mm with self-sealing strip |
| Cushioning | Yes | Yes, with excellent rebound properties |
| Moisture Resistance | Yes | Yes |
| Mould Resistance | Yes | Yes |
| Non-Absorbent / Rot Resistant | Yes | Yes |
| Acoustic Information | 45% reduction compared with no underlay | STC rating 66 dB / test result 69 dB; IIC rating and result 72 dB |
| Thermal Properties | Minimal | Increased |
| Anti-Crush / Rebound | Not specifically listed | Excellent anti-crush and rebound properties |
| Anti-Static | Not listed | Yes |
| Anti-Allergenic | Not listed | Resistance to bacteria and dust mites |
| Joint Installation | Overlap to be taped | Self-sealing peel strip |
Why Choose FINIXPE Acoustic Underlay?
Combilay and FINIXPE fulfil different requirements. Combilay remains a practical and cost-effective traditional option, while FINIXPE provides additional listed characteristics where enhanced performance is required.
Practical and Cost-Effective
Combilay is suitable where the requirement is for a traditional underlay providing cushioning, moisture resistance, protection from moisture egress and basic sound reduction.
Its 2mm aerothene construction provides a straightforward flooring underlay solution for compatible installations.
Premium Acoustic Performance
FINIXPE acoustic underlay is the premium option where increased acoustic properties, excellent rebound, increased thermal properties, anti-static performance and anti-allergenic characteristics are priorities.
Its integrated moisture membrane and self-sealing overlap also provide convenient installation.
For premium laminate flooring and compatible floating engineered wood flooring installations, FINIXPE provides a high-performance supporting foundation with advanced listed acoustic and rebound properties.
Underlay compatibility must always be confirmed against the specific flooring product, installation method, substrate and site conditions.
FINIXPE Acoustic Underlay FAQs
What is FINIXPE acoustic underlay?
FINIXPE acoustic underlay is a 2mm premium underlay manufactured from Irradiated Cross-Linked Polyethylene and laminated to an 80-micron virgin HDPE moisture membrane.
What does IXPE mean?
IXPE stands for Irradiated Cross-Linked Polyethylene. FINfloor describes it as an extra-fine foam manufacturing technology that provides advanced moisture protection, cushioning and acoustic characteristics.
How thick is FINIXPE?
FINIXPE is 2mm thick.
What is Combilay made from?
Combilay consists of 2mm polyethylene closed-cell foam, commonly called aerothene, laminated to an 80-micron moisture membrane.
Does FINIXPE absorb sound?
FINfloor’s technical specification describes FINIXPE as sound absorbent rather than reflective and lists increased acoustic properties and sound absorption among its benefits.
What are the FINIXPE STC figures?
FINIXPE technical information lists an STC rating of 66 dB and an STC test result of 69 dB.
What are the FINIXPE IIC figures?
The FINIXPE technical specification lists an IIC rating and test result of 72 dB.
Does FINIXPE include a moisture barrier?
Yes. FINIXPE incorporates an 80-micron virgin HDPE moisture membrane laminated to the IXPE foam.
Is FINIXPE mould resistant?
Yes. FINfloor’s technical specification lists FINIXPE as moisture and mould resistant, non-absorbent and rot resistant.
Is FINIXPE anti-allergenic?
FINIXPE is listed as anti-allergenic with resistance to bacteria and dust mites.
What is the difference between FINIXPE and Combilay?
Combilay uses traditional polyethylene closed-cell aerothene foam. FINIXPE uses cross-linked IXPE foam and includes additional listed characteristics such as increased acoustic properties, excellent rebound, increased thermal properties, anti-static performance and anti-allergenic characteristics.
Can FINIXPE be used with engineered wood flooring?
FINIXPE can be considered for compatible floating-floor installations. Compatibility should always be confirmed against the specific engineered flooring product, installation method and site requirements.
Build Your Floor from the Foundation Up
While Combilay continues to provide a suitable and cost-effective traditional underlay solution, FINIXPE acoustic underlay adds advanced acoustic properties, rebound, increased thermal characteristics and convenient installation features.
When investing in quality flooring, selecting an appropriate underlay helps support the comfort and performance of the complete floating-floor system.
View Laminate FlooringView Engineered HardwoodVisit FINfloorProduct information and performance figures are based on the FINfloor FINIXPE and Combilay technical specification sheets. Acoustic figures relate to the stated test methods. Combilay’s percentage sound-reduction figure and FINIXPE’s STC/IIC values are different acoustic measurements and should not be treated as direct equivalents. Flooring and underlay compatibility should always be confirmed for the individual product and installation.