Posted by Spycor Building on Aug 27th 2026
DELTA®-DRAIN is a two-layer drainage membrane manufactured by Dörken Systems Inc., made of a dimpled polypropylene (PP) core heat-bonded to a Typar® polypropylene geotextile fabric. Installed against a below-grade foundation wall alongside a primary waterproofing membrane, it creates a drainage channel that routes groundwater to the footing drain and helps relieve hydrostatic pressure against the foundation assembly. Dörken rates it for installation depths up to 12 feet and a service life expectancy of over 25 years.
What Is DELTA-DRAIN?
DELTA®-DRAIN is a foundation drainage board manufactured by Dörken Systems Inc., a DÖRKEN GROUP company, for residential and light commercial below-grade construction. It's a drainage and protection layer, not a primary waterproofing membrane — it's designed to be installed alongside liquid-applied or sheet-applied waterproofing, not in place of it.
Its role is to manage the water that reaches the foundation wall, help relieve hydrostatic pressure, and protect the waterproofing membrane underneath from damage during backfill.
How Does DELTA-DRAIN Work?
DELTA®-DRAIN combines two layers that work together:
- The dimpled polypropylene core creates a continuous air gap and drainage channel along the foundation wall, running from grade down to the footing.
- The heat-bonded Typar® geotextile filters incoming groundwater, letting water pass through while blocking silt and clay particles that would otherwise clog the drainage channel over time.
Groundwater moving toward the foundation passes through the geotextile and into the air gap, where it drains by gravity down to the perimeter footing drain rather than collecting against the wall. By providing this path for water to drain toward the footing drainage system, DELTA®-DRAIN helps reduce hydrostatic pressure against the foundation assembly. During backfill, the dimpled core also absorbs impact from rocks and debris that would otherwise risk damaging the waterproofing membrane beneath it.
DELTA®-DRAIN should be oriented and installed according to Dörken's published installation instructions for the specific foundation assembly. See our [installation guide] for step-by-step detail.
What Is DELTA-DRAIN Made Of?
Per Dörken's technical data sheet, DELTA®-DRAIN is a two-layer geocomposite:
- Drainage core: black, dimpled polypropylene (PP)
- Geotextile: grey, non-woven polypropylene Typar® fabric, heat-bonded to the dimple crowns
The polypropylene core provides compressive strength, impact resistance, and resistance to chemical and environmental stress cracking. The geotextile is rot-proof and highly water-permeable.
DELTA-DRAIN Technical Specifications
| Specification | Value | Test Standard |
|---|---|---|
| Drainage core material | Polypropylene (PP) | — |
| Geotextile material | Polypropylene (PP), Typar® | — |
| Dimple height | 5/16" (8 mm) | ASTM D6364-06 |
| Compressive strength | ~5,200 psf (250 kN/m²) | ASTM D6364-06 |
| Air-gap volume between dimples | 0.13 gal/ft² (5.3 L/m²) | ASTM D4716-08Z |
| Water penetration resistance (core) | >120 psi (815 kPa), watertight | AATCC 127-1995 |
| Flow rate @ hydraulic gradient 1.0 | 5.2 gal/min/ft (65 L/min/m) | ASTM D4716-08 |
| Flow rate @ hydraulic gradient 0.1 | 1.4 gal/min/ft (17.4 L/min/m) | ASTM D4716-08 |
| Temperature range | -22°F to +176°F (-30°C to +80°C) | — |
| Weight per unit area | ~21 oz/yd² (715 g/m²) | ASTM D5261-92 |
| Roll size (6' width) | 6' x 65'7" (1.83 m x 20 m), 54 lbs | — |
| Roll size (8' width) | 8' x 65'7" (2.45 m x 20 m), 71 lbs | — |
| Maximum installation depth | Up to 12 ft (4 m) | — |
| Service life expectancy | >25 years (pH 4–9, below 77°F/25°C) | — |
| UV exposure limit | Do not expose more than 30 days | — |
For installations exceeding 12 feet, or high-load commercial and civil applications, Dörken's commercial-grade drainage products (DELTA®-DRAIN 2000/6000/6200 HI-X, DELTA®-TERRAXX) are the correct spec.
Where Is DELTA-DRAIN Used?
DELTA®-DRAIN is used on residential and light commercial foundation walls, and — within its rated depth and load limits — on retaining walls and other below-grade applications supported by Dörken's published guidance. It's typically specified where soil conditions or water flow call for active filtration in addition to a drainage air gap, such as clay-heavy or high-water-table sites.
When Should Contractors Consider DELTA-DRAIN?
DELTA®-DRAIN is typically specified by:
- Residential and light commercial general contractors on below-grade foundation waterproofing for new builds
- Waterproofing and foundation repair specialists working in clay-heavy or high-water-table conditions
- Civil contractors on retaining walls and drainage applications within its 12-foot depth rating
- Purchasing managers and estimators sourcing bulk roll quantities for multi-lot developments
If your project falls outside the 12-foot depth rating or involves heavier commercial loads, see Dörken's commercial-grade drainage line instead.
Buy DELTA-DRAIN From Spycor Building Products
Spycor Building Products stocks Dörken's DELTA®-DRAIN in multiple roll sizes for residential, commercial, and foundation drainage projects.
Choose the roll size that best fits your foundation wall height and project coverage requirements.
Shop DELTA®-DRAIN:
DELTA®-DRAIN 6' x 65.6' Rolls →
DELTA®-DRAIN 8' x 65.6' Rolls →
Frequently Asked Questions
What is DELTA®-DRAIN made of?
A two-layer geocomposite: a black, dimpled polypropylene (PP) drainage core heat-bonded to a grey, non-woven polypropylene Typar® geotextile.
Does DELTA®-DRAIN replace foundation waterproofing?
No. DELTA®-DRAIN is a drainage and protection layer, installed alongside a primary liquid-applied or sheet-applied waterproofing membrane. It is not itself rated as a standalone waterproofing barrier.
How deep can DELTA®-DRAIN be installed?
Up to 12 feet (4 m), per Dörken's technical data sheet. Deeper excavations require Dörken's commercial-grade drainage products.
What is the compressive strength of DELTA®-DRAIN?
Approximately 5,200 psf (250 kN/m²), tested to ASTM D6364-06.
How long does DELTA®-DRAIN last?
Dörken rates its service life expectancy at over 25 years, provided soil pH stays between 4 and 9 and temperatures remain below 77°F (25°C). It should not be exposed to UV light for more than 30 days prior to backfill.
What's the difference between DELTA®-DRAIN and DELTA®-MS?
DELTA®-MS is a dimpled membrane without DELTA®-DRAIN's bonded geotextile layer. DELTA®-DRAIN adds that layer for active filtration alongside drainage.
What roll sizes does DELTA®-DRAIN come in?
6' x 65'7" (54 lbs) and 8' x 65'7" (71 lbs), per Dörken's published dimensions.
Where can I buy DELTA®-DRAIN?
