Delta FL

The perfect plastic subfloor system for concrete and slab on grade floors.

This air-gap membrane is made up of a special high-density polyethylene resin (FDA approved), providing a dimpled surface with outstanding compressive strength, impact resistance and long-term performance.


Product Name: DELTA®-FL

Color: Grey

Material: High-density Polyethylene (HDPE)

Dimple Height: appx. 5/16″ (8mm)

Compressive Strength: apprx. 5,200 psf (250 kN/m²)

Air-gap Volume Between Dimples: apprx. 7,9 l/m²

Temperature Range: -22°F to +176°F  (-30°C to +80°C)

Roll Size:

  • 5′ x 65.6′  (1.52 m x 2.0 m)
  • 3.5′ x 30′ (1.07 m x 9.14 m)


Sheet Size: 4′ x 8′  (1.22 m x 2.45 m)

Toxicity: non-toxic, non-polluting

Water Permeability (EN ISO 11058): 8 · 10² m/s

Service Life Expectancy: > 25 years (at pH between 4 and 0 and temperature < 25°C). The membrane should not be exposed to UV light for more than 30 days.

Delta FL Product Description

DELTA®-FL is a uniquely dimpled, heavy-duty grey plastic membrane that keeps you and your family warm and comfortable in your basement, or any room in the house with a concrete, slab-on-grade floor. The membrane is installed with its dimples down to create a 5/16-inch thick air space above the slab, and can be covered with a plywood subfloor and topped off with carpet or flooring systems.

DELTA®-FL on concrete floors protects sensitive materials by exploiting the concept of vapor pressure – that is, water vapor seeks to equalize its pressure by moving from areas of high pressure to areas of low pressure.

In a conventional basement, dry air in the living space acts as a magnet for water vapor seeping up through the concrete. But with the DELTA®-FL system, the space between the dimples provides a sufficient air-gap to equalize the water pressure above and below the concrete slab.

Though the air in the living space is completely isolated from the system, DELTA®-FL is designed to allow small amounts of water vapor into the room to maintain a healthy humidity level.

The membrane also provides a thermal break that generates instant comfort and warmth for your basement. DELTA®-FL is an inert material. The air-gap membrane has an outstanding compressive strength of > 250 kN/m², is extremely tough and rugged and can withstand heavy loads which allows for any finishing on top of the membrane.

The reduction in head room is minimal and the product is extremely easy and fast to install. DELTA®-FL comes with a 20 year product warranty.

PDF DownloadInstallation Instructions | PDF DownloadProduct Brochure

Delta FL Product Application

DELTA®-FL functions in conjunction with wood laminate floors and is a simple new solution to create a beautiful, high-performance basement floor, easy enough for the average homeowner to install. Once DELTA®-FL and plywood sheets are laid out, a variety of floor coverings can be installed:

  • carpeting with rubber underlay
  • linoleum (on top of multiply board)
  • tiles – peel & stick – hardwood flooring
  • laminate floors (floating directly on top of DELTA-FL)