Key advantages
- A thickness of only 4 mm
- Impact noise reduction in floor systems
- Approx. 8 dB in a bonded installation with a ceramic finish
- Up to approx. 15 dB in the loose-laid test assembly
- Allows tiles to be laid directly on top of the board
- Acts as a decoupling layer between the substrate and the floor covering
- High compressive strength – 15 N/mm²
- Suitable for imposed loads of up to 5.0 kN/m²
- Suitable for ceramic tiles, natural stone and parquet
- Also suitable for carpet, linoleum, PVC and synthetic coverings once a levelling layer has been applied
- Suitable for installation over water-based underfloor heating
Why this product
The 4 mm Steptherm 800 is designed for cases where you want to improve the acoustics of a floor without adding significant thickness to the system. As well as reducing impact noise, the board forms a flexible decoupling layer between the substrate and the floor covering, helping to reduce the transfer of shear stresses and movement from a cracked substrate to the finish layer.
Technical description
Steptherm 800 – 4 mm is a polyester-fibre board with high tensile and compressive strength, designed for decoupling and impact noise reduction on mineral substrates.
The board is compatible with standard polymer-modified adhesives and adhesive mortars and serves as a base for a wide range of floor coverings. Its structure allows controlled deformation within the board, helping to reduce the transfer of stresses from cracks and moving joints in the substrate to the rigid covering above.
Applications
Suitable for installation under ceramic tiles, natural stone and parquet, as well as under carpets, linoleum, PVC and synthetic coverings once a suitable levelling layer has been applied. It can be laid on screed, trowelled concrete surfaces and existing rigid substrates, and is particularly suited to renovations and floor systems with height restrictions.
Technical specifications
Type: Decoupling and impact sound insulation board
Material: Polyester fibres
Thickness: 4 mm ± 0.5 mm
Dimensions: 1000 × 600 mm
Area per board: 0.60 m²
Weight per m²: 3.2 kg/m² ±5%
Estimated weight per board: approx. 1.92 kg
Compressive strength: 15 N/mm²
Flexural strength: 4 N/mm²
Tensile strength: 6.0 N/mm²
Maximum imposed load: 5.0 kN/m²
Thermal conductivity λ: 0.11 W/(m·K)
Application area: Indoor
Acoustic performance
Steptherm 800 – 4 mm is designed to reduce impact noise caused by footsteps, movement and direct impacts on the floor.
Manufacturer tests to DIN ISO 10140 show an impact noise reduction of approx. 8 dB in a bonded system with a ceramic finish, and up to approx. 15 dB with the complete test assembly loose-laid.
Fire performance
The product is classified as:
Efl according to DIN EN 13501-1
The suffix fl indicates a reaction-to-fire classification for a product intended for flooring applications.
Standards
- DIN ISO 10140 – Impact sound insulation testing
- DIN EN 13501-1 – Reaction-to-fire classification Efl
- DIN 53456 – Compressive strength
- DIN 53453 – Flexural strength
- DIN 53457 – Tensile strength
- DIN 18202 – Substrate flatness requirements
- DIN 1055 – Substrate load-bearing capacity requirements
Installation
The boards are bonded to a level, stable, load-bearing substrate and laid in a staggered half-bond pattern. Leave a suitable gap from walls and vertical elements; the manufacturer recommends using a perimeter insulation strip. The boards can be cut with a good-quality utility knife or a suitable diamond disc.
Example system under tiles:
Substrate / screed → C2 tile adhesive → Steptherm 800 – 4 mm → waterproofing layer if required → C2 adhesive → tiles and flexible grout
Ceramic tiles, natural stone and parquet can be installed directly on top of Steptherm using suitable polymer-modified adhesives. The minimum tile area is 200 cm², and natural stone must be at least 10 mm thick.
For carpet, linoleum, PVC and synthetic coverings, a suitable levelling layer must be applied over the board before the covering is installed.
Manufacturer data
Manufacturer: BOSIG GmbH
Product: Steptherm 800 – 4 mm
Country of manufacture: Germany
Intended use: Decoupling and impact noise reduction in floor systems
Size: 1000 × 600 × 4 mm
Quantity per pallet: 200 boards
Area per pallet: 120 m²
