Many project managers and installers believe that a thicker underlay is automatically better. However, that is a misconception. The quality of an underlay for hard floors is determined by its compressive strength (CS value) – not by its thickness.

Why is compressive strength crucial?

• A high CS value (kPa) prevents indentation and wear.
• Furniture or castor chairs exert continuous pressure.
• Too low a compressive strength can cause damage and loss of product warranty.

How to avoid this mistake?

• • Always check the technical specifications and load capacity of the underlay.
  • Choose an underlay that has been tested for castor chair load, especially in areas of heavy use.
  • Don’t be misled by thickness: a thin, firm underlay can be better than a thick, soft one.
    
    
  This way, you ensure a floor build-up that withstands daily use – without compromising comfort or durability.

Many people believe that an underlay automatically compensates for all irregularities. However, this does not apply in all situations – and certainly not for larger level differences.

Why is this a problem?

• An insufficiently levelled subfloor leads to visible unevenness.
• This can cause telegraphing.
• Wrong assumptions delay handover or increase remedial costs.

How to fix it?

• Use an underlay only within the tolerances for which it’s intended.
• For slight irregularities (up to 2–3 mm) a system like Floorfixx is effective:

• • Levels slightly undulating floors.
  • Immediately walkable, dry system.
  • Ideal for fast renovation projects.

This way, you ensure the underlay does what it should – and you work smoothly towards an easy installation and handover.

When selecting underlays, certification is often not taken into account. Yet quality marks and test results are essential to demonstrate performance.

Why certification matters:

• Our products have been extensively tested by independent institutions.
• Certificates reinforce the justification of quality and safety, giving you a stronger position in the market.
• Certification allows you to make clear agreements and avoid disputes with clients and end users.
• In specific sectors (such as maritime or sustainable construction), certificates provide access to projects and markets where they are a requirement.

Key certificates:

• TÜV certificate: sound-reducing underlays.
• Fire certificate: fire-retardant underlays.
• IMO certificate: required for maritime applications.

Practical tip:

By working with certified underlays, you give clients and end users demonstrable assurance – and avoid disputes at handover.