Overlay Boards

Plain 18mm XPS300 overlay board without aluminium foil for 12mm pipe.

• Dimensions: 1200mm × 600mm × 18mm (covers 0.72m² per board)
• Material: High-density extruded polystyrene (XPS) foam
• Compressive Strength: 300kPa – Robust load-bearing capability for residential and light commercial floors (handles foot traffic, furniture, etc., without significant compression)
• Thermal Conductivity (λ): Typically 0.034–0.035 W/(m·K) – Strong downward heat loss reduction for efficient UFH performance
• Surface: Plain / uncoated or basic finish (no aluminium foil heat-spreader layer) – Ideal for setups requiring direct screed, self-levelling compound, or adhesive tile bonding
• Grooves: Precision pre-routed channels optimised for 12mm underfloor heating pipe (standard 150mm centres with smooth radius returns for easy looping and minimal pipe stress)
• Design: Grooved only – No pre-installed heating circuit/pipe, no foil (flexible for custom layouts and dry/wet systems)
• Benefits at a Glance: Low build-up height, lightweight, closed-cell waterproof structure, high compressive strength for durability, quick install – push pipe into grooves (no clips needed in most cases), then cover with levelling screed or tiles.

Suitability:

• underfloor heating installations on concrete/screed bases,  or retrofit projects.
• where minimal floor height increase matters, and foil isn’t required (e.g., thicker screed/levelling for even heat distribution, or direct tile/wood finishes).

Installation

Boards must be bonded to the subfloor. Lay in a staggered brick-bond pattern, insert 12mm PEX/PE-RT pipe into channels, apply primer, then self-levelling compound, and final floor covering for a fast, solid system.