Cosella Dorken DELTA FL Subfloor for basements
Cosella Dorken DELTA FL Subfloor for basements - Image 1 of 0
Cosella Dorken DELTA FL Subfloor for basements - Image 2 of 0
Cosella Dorken DELTA FL Subfloor for basements - Image 3 of 0
Cosella Dorken DELTA FL Subfloor for basements - Image 1 of 0
Cosella Dorken DELTA FL Subfloor for basements - Image 2 of 0
Cosella Dorken DELTA FL Subfloor for basements - Image 3 of 0
Cosella Dorken DELTA FL Subfloor for basements - Video 4 of 1
Cosella Dorken DELTA FL Subfloor for basements - Image 1 of 0
Cosella Dorken DELTA FL Subfloor for basements - Image 2 of 0
Cosella Dorken DELTA FL Subfloor for basements - Image 3 of 0
Cosella Dorken DELTA FL Subfloor for basements - Video 4 of 1

DELTA®-FL Plastic Sub-Floor

Dörken Systems Inc.
113 Reviews
Free Shipping! (Large Project Discounts Available)
No Open Seams • No Moisture • No Mold!

Click image to see how competition handles moisture!
Click image for Delta-FL easy installation!
Product Code: DLFL
UPC Code: 8-07595-60010-9
Usually Ships in 24 to 48 Hours

For a warm and comfortable basement, choose the Dorken DELTA®-FL Subfloor. Its dimpled, rugged gray plastic membrane provides a seamless mold and moisture barrier for any concrete, slab-on-grade floor in your home. With the right moisture protection, you can turn a damp, moldy basement into a safe and livable family room or workshop. This subfloor moisture-management system helps concrete basement floors dry out so the finished floor above doesn't absorb the water. You'll have a lower level worth spending time in when it has this Delta-FL underlayment for sale at Spycor Building Products.

High-Quality Subflooring

Every roll of DELTA-FL plastic subfloor is made of high-density polyethylene (HDPE) that has dimples added to each side. By using dimpled polyethylene, homeowners create an air cavity to equalize water pressure and improve ventilation. While small amounts of moisture are allowed into the basement so the air won't be completely dry, you'll avoid excess humidity that can lead to warped floors, rotted beams and mold. As an added bonus, your finished floor is isolated from the concrete so it doesn't absorb the cold from being below ground level. This means it will be much warmer downstairs.

Affordable Basement Moisture Control

We have low prices on this premium subflooring system that can be used with many different coverings. Install it underneath hardwood floors, floating laminate floors, carpeting and anything else you want in the basement. If you want to learn more about the DELTA-FL system, watch our product and installation videos below or scroll down for a full overview of its features. You can also visit ourProduct Questions page for even more information.

*Delivered Rates Apply to the contiguous 48 U.S. states. For freight charges outside this region, please e-mail [email protected].

(DELTA®-FL products usually ship within 24 hours)

**Buy One Roll of Tuck Tape per Roll of Delta-FL

The Science Behind Superior Design

DELTA-FL uses the science behind vapor pressure, which is that the vapor moves from high pressure to low pressures areas to equalize its pressure. In a standard basement, the dry air in the room is a magnet for water vapor that seeps through the concrete. However, this subfloor system works differently, since the space within the material's dimples equalizes the water pressure both above and below the concrete. Although the air in the room is isolated from the system, the DELTA-FL subfloor allows small amounts of water vapor into the room. This helps to maintain optimal humidity for greater comfort, while sensitive flooring materials are protected.

DELTA-FL Advanced Materials and Design

The DELTA-FL subfloor is constructed from high-density, impact-resistant polyethylene (HDPE) material, featuring an air-gap membrane. It is an inert material that is extremely rugged, withstanding heavy loads and suitable for any floor finishing. The unique design provides an effective capillary break and vapor barrier, for a drier basement. This thermal break makes the basement floor warmer, with whatever floor covering you use. This lightweight material has exceptional compressive strength of greater than 5,200 psf (250 kN/m2). Even with this added layer of projection, there's minimal head room reduction — just 8 millimeters.

DELTA-FL Subfloor System - Easy Application

This advanced, high performance subfloor comes in easy-to-use sheets and in two roll sizes. Installation of DELTA-FL is fast and simple and can be done by the average homeowner. It is installed with the dimple side down, which creates a 5/16-inch ventilated air space above the slab. Use DELTA-MOISTURE PROOF TAPE for taping the seams, to keep moisture from moving into the joint areas. After laying down DELTA-FL and plywood sheets on top of the concrete floor, you can put down the flooring surface of your choice:

  • Laminate floors (directly on top of the DELTA-FL)
  • Carpeting with rubber underlay, vinyl flooring or hardwood floors (on top of plywood boards)
  • Linoleum (on top of multiply board)

DELTA-FL subfloor comes with a 20-year product warranty.

*Delivered Rates Apply to the US contiguous 48; For freight charges outside this region, please e-mail [email protected].

DELTA®-FL products usually ship within 24 hours.

Product name
High Density Polyethylene (HDPE)
Dimple height
apprx. 5/16" (8 mm)
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
4' 9" x 68' 6" (1.46 m x 20.9 m) 328 sf (30.5 m²) (1.52 m x 20.0 m)
47 lbs
Sheet size
Sheets No Longer Available
non-toxic, non-polluting
Water permeability (EN ISO 11058)
8 · 10-² m/s
Service life expectancy
Ø25 years (at pH between 4 and 0 and temperature < 25°C).
ØThe membrane should not be exposed to UV light for more than 30 days.
DELTA®-FL functions as an effective vapor barrier in conjunction with wood laminate floors and many other common floor coverings, and is a simple new solution to create a beautiful, high-performance basement floor.

The leight-weight product comes in two different roll sizes, as well as easy-to-handle sheets. It is fast and 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:
- laminate floors (floating directly on top of DELTA®-FL)
- carpeting with underlay (on top of plywood board)
- vinyl flooring (on top of plywood board)
- hardwood flooring (on top of plywood board)

Seams are simply taped with DELTA®-MOISTUREPROOF TAPE to ensure that moisture cannot migrate inwards through the joint areas.
Product CodeNameOur PriceQty
Product Code:DLFL-ROLL-4.9ft-DELTA®-FL Subfloor ROLL 4' 9" x 68' 6" (328 sqft)Our Price:$274.95
Product Code:DLFL-ROLL-3.5ft-DELTA®-FL Subfloor ROLL 3'6" X 30' (105 sqft)Our Price:$97.45
Product Code:DLFL-SKIDDELTA®-FL Subfloor SKID 4' 9" x 68' 6" (11-Rolls/3608 sqft)Our Price:$2,495.00
Product Code:DLMTDELTA®-MOISTUREPROOF TAPE (2.35 in x 108 ft)Our Price:$17.23


Average Customer Review:
( 113 )
Eric V. from Corryton, TN United States
October 3, 2023
Customer service is A++
David was awesome to work with. Will highly recommend. Thanks,Eric
Was this review helpful to you?
Damian Crews from Lexington, NC United States
October 3, 2023
lack of service after the sale
called with a few questions and received knowledgeable and courteous customer service. Placed an order and shipping was fast but I never received a shipping confirmation or status / information. Overall good experience and very satisfied with the quality of the product I ordered.
Was this review helpful to you?
Anonymous Person from Billerica, MA United States
September 30, 2022
We use this delta drain product on our installations, it is easy to use and serves its purpose well. Great product that gets delivered on time every time.
Was this review helpful to you?
Peter S. from Solon, OH United States
May 16, 2022
Delta FL
Awesome product !! I’m using this in my basement as a liner beneath the subfloor. I know it’s costly but it’s worth it In the long run. I don’t know why people put carpet and laminate directly on top of concrete but that is not the correct way to finish a floor. This product allows air and moisture a place to escape and to dry. Similar to Tyvek on a homes sheathing. Without a cavity to dry in mois
... view more
Was this review helpful to you?
Dennis Fox
March 16, 2022
Spycor came thru in expediting a shipment of Delta-FL to me. Lowes totally failed me in shipping to me for over two months!! I will never use them again. Thank you Spycor for immediately shipping to me. You are awesome!
Was this review helpful to you?