Low Water Absorption FL300 XPS Insulation Board Closed Cell Panel For Damp Floor Application

Most floor insulation fails slowly, through water rather than load. The FL300 board is the grade chosen when the floor is at risk of damp: ground floors without a reliable membrane, refurbishment over an existing slab, and floors that are laid and then left exposed to weather. Water absorption of 1.5% by volume or less is the number that matters here, because a board that holds water loses its thermal performance and never recovers it.

Closed cells keep water at the surface of the foam rather than inside it, and the shiplap edge lets panels overlap so the joint stays closed as the slab moves. At 60 mm and 300 kPa the board handles normal domestic and commercial floor loads while remaining light enough to handle in full sheets. The FL300 XPS insulation board is supplied in standard sizes of L 1200 / 2400 mm, W 600 / 1200 mm, THK 30 - 140 mm, and the board can be cut on site with a fine toothed saw or a hot wire, which keeps the cut face closed.

Technical Data

Applications

Used on standard floors where moisture at the slab is the main threat to the insulation layer.

• Standard building floor insulation above or below the slab
• Refurbishment over an existing ground floor slab
• Ground floors where the damp proof membrane is imperfect
• Floors laid before the building is closed to weather
• Insulation under floating screeds and dry deck systems

Key Advantages

• Water absorption of 1.5% by volume or less keeps conductivity stable in damp floors.
• Closed cell foam does not wick water across the floor build-up.
• Shiplap edges overlap so joints stay closed as the slab moves.
• 300 kPa compressive strength suits domestic and commercial floor loads.
• Sheets are light enough for one person to place, which speeds up laying.

Each Low Water Absorption FL300 XPS Insulation Board is checked for thickness, compressive strength and dimensional stability before it is packed, and the batch figures travel with the delivery note. Low Water Absorption FL300 XPS Insulation Board sheets are packed on edge on pallets, strapped and wrapped, so the edges and the faces arrive as they left the line.

Installation Notes

• Boards are laid with joints staggered and edges fully engaged over the whole face.
• Surfaces in contact with adhesive or membrane are cleaned and primed before the board is bedded.
• Boards are cut oversize by 10 mm where a tight fit into a frame or reveal is needed, then trimmed.
• Finished layers are protected from site traffic until the covering layer is in place.

FAQ