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KEY BENEFITS

  • Relieve tensions
  • Stabilizes installation
  • Easy to cut and install
  • Very low emissions (EC 1 certified)

CHARACTERISTICS

  • Composition: Premium polyester fleece.
  • Format: Precision-cut boards measuring $0.6 \times 1\text{m}$.
  • Available Thicknesses:
    • RENO U504: 4 mm.
    • RENO U509: 9 mm.
    • RENO U515: 15 mm.
  • Acoustic Performance (Impact Sound Improvement):
    • 4 mm and 9 mm: 10 dB.
    • 15 mm: 13 dB.
  • Weight & Density :
    • 4 mm: 3.8 kg/m².
    • 9 mm: 7.2 kg/m².
    • 15 mm: 12 kg/m².

Decoupling underlayment boards for multiple substrates

These decoupling underlayment boards are compatible with a wide range of common construction substrates, including:

  • Concrete and cementitious screeds
  • Calcium sulphate screeds
  • Mastic asphalt screeds
  • Existing ceramic tiles and natural stone
  • Wooden and metallic substrates

This versatility makes them particularly effective as decoupling boards for concrete floors, ensuring reliable performance across varied site conditions.

Underlay for ceramic tiles and floor coverings

RENO MULTIBOARD systems function as an underlay for ceramic tiles, providing a stable base prior to tile installation. Once bonded to the substrate using suitable adhesives, tiles can typically be installed after curing, supporting efficient project timelines.

They are also suitable for:

  • Parquet and laminate flooring
  • Engineered and solid wood floors
  • Soft floor coverings (with levelling compound overlay)
SDS

Application process: RENO U504 / U509 / U515 MULTIBOARD

Quick Application Steps (On-Site Guide)

  • Prepare: Ensure subfloor is clean, level, dry and primed if required
  • Adhesive: Apply suitable Bostik adhesive evenly to the substrate
  • Install: Lay boards into adhesive, press firmly and avoid cross joints
  • Secure: Tape joints and maintain perimeter gaps
  • Finish: Install flooring or levelling layer after ~24 hours

1. Subfloor preparation

A properly prepared base is essential for board performance:

  • Substrate must be sound, dry and free from contaminants such as dust, grease or oil
  • Remove weak layers, coatings and adhesive residues using mechanical preparation
  • Vacuum thoroughly to eliminate loose material
  • Timber substrates must be stable and securely fixed
  • Smooth or dense surfaces should be mechanically abraded and degreased
  • Uneven substrates must be levelled prior to board installation
  • Weak or dusty surfaces may require consolidation with a suitable primer

All substrates should comply with site standards before installation begins.

2. Installation preparation

  • Acclimatise boards at room temperature for at least 24 hours before use
  • Select appropriate adhesive depending on floor type (e.g. MS, PU or tile adhesive)
  • Apply adhesive evenly using the correct notched trowel
  • Do not spread more adhesive than can be covered within working time

Important: Ensure full adhesive transfer to the underside of the boards.

3. Installation

  • Lay boards directly into the adhesive bed and press down firmly
  • Avoid aligning joints (stagger boards to prevent cross joints)
  • Cut boards as required using a knife or saw
  • Maintain perimeter gaps to prevent sound bridging
  • Use a roller or firm pressure to ensure proper bonding
  • Once installed, secure joints with tape to prevent ingress of levelling compounds or adhesives

Designed to provide decoupling, sound reduction and thermal insulation beneath floor finishes.

4. Finishing & curing

  • Allow adhesive to cure before proceeding (~24 hours depending on system)

Typical next steps:

  • Tiles: install directly after curing
  • Wood flooring: install once boards are bonded
  • Soft flooring: apply 3–6 mm levelling compound before final finish

5. Underfloor heating

  • Switch off heating systems 48 hours before, during, and for at least 48 hours after installation
  • Gradually bring heating back to operating temperature after installation

Common mistakes to avoid

  • Installing onto uneven or unprepared substrates
  • Poor adhesive coverage leading to hollow spots
  • Aligning board joints (creating weak points)
  • Not maintaining perimeter gaps (risk of sound bridging)
  • Skipping joint taping before applying levelling compounds
  • Applying excessive adhesive beyond working time
  • Ignoring acclimatisation period prior to installation

Frequently Asked Questions

A decoupling board is used to relieve stress between the subfloor and floor covering, helping prevent cracks or movement from transferring. RENO U504/U509/U515 MULTIBOARD provides stress relief, sound insulation and thermal insulation prior to installing flooring.

Decoupling boards such as RENO U504/U509/U515 MULTIBOARD are installed by applying a suitable adhesive onto the subfloor and placing the boards firmly into the adhesive layer. Boards should be pressed down evenly, with joints secured and aligned properly before installing the final floor covering.

Floor insulation can be improved by installing insulating underlays or decoupling systems. RENO U718 SILENTCORK improves acoustic and thermal performance, while RENO U504/U509/U515 MULTIBOARD provides sound and thermal insulation as well as stress relief between the subfloor and floor covering.

RENO U718 SILENTCORK is mainly focused on acoustic insulation and walking comfort, offering impact sound reduction up to 18 dB. RENO U504/U509/U515 MULTIBOARD is a decoupling and insulating board that provides stress relief as well as sound and thermal insulation. RENO U718 SILENTCORK is more sound-focused, while RENO U504/U509/U515 MULTIBOARD also supports structural decoupling.

Underlays are presented as products that provide stability, reduce noise and enhance comfort, helping create a smooth and durable foundation for flooring renovation. Depending on the product, they can also stabilize weak subfloors, relieve tensions or bridge critical areas.

The available underlay solutions include an impact sound insulation underlay, reinforcement mesh for substrate stabilization, fiberglass reinforcement fleece for crack and joint bridging, a stress-relieving and decoupling underlay, and decoupling and insulating polyester boards.

Underlays improve flooring performance by reducing impact sound, improving walking comfort, stabilizing installations over critical subfloors, relieving tensions and providing stress relief between the substrate and the floor covering. Some systems also add sound and thermal insulation.

To stabilize critical or moving substrates, use decoupling or reinforcement systems such as RENO U750 FLEECE or RENO U504 MULTIBOARD. These products help relieve tensions and ensure stability before installation of floor coverings, but they do not directly repair cracks.

A decoupling system in flooring is an underlay solution that relieves tensions or stress between the subfloor and the floor covering. RENO U750 FLEECE is described as a stress-relieving and decoupling underlay, and  RENO U504/U509/U515 MULTIBOARD is described as a decoupling board for stress relieving underlayment.

A complete underlayment solution for modern flooring systems

The RENO MULTIBOARD systems provide a comprehensive underlayment solution for construction professionals seeking performance, reliability and ease of installation across a wide range of flooring applications.

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