By NORMA Group
EZflow® Gravel-Free French Drain System
Applications
- Use for surface and subsurface drainage problems on lawns, plant beds, and sports fields, and against building foundations and basements, retaining walls, and raised planters
- Works as an infiltration system to capture adjacent groundwater and slowly release it into the surrounding soil, or redirect water to a connected pipe for proper release downstream
- Works in conjunction with other NDS products such as catch basins, channel drains, Flo-Well® dry well and pop-up emitters as part of a complete stormwater drainage system
Installation & Maintenance
- Ready to install, and in half the time of traditional French drain systems; recommend install with a minimum 1% slope for positive drainage
- Works best in non-clay soils
Materials & Sustainability
- Poly-Rock™ made of expanded polystyrene; mesh made of polyethylene geotextile
- Products with pipe: single-wall corrugated slotted drain pipe is made of high-density polyethylene
- Onsite stormwater management protects the watershed downstream, and limits excess runoff which can lead to negative impacts such as erosion, pollution, and flooding
Product Models
Literature & Resources
Download
NDS EZFlow French Drain Technology Brochure
application/pdf | 5 MB
Download
NDS EZflow® Gravel-Free French Drain with Pipe Tech Spec
application/pdf | 419 KB
Download
NDS EZflow® Gravel-Free French Drain Without Pipe Tech Spec
application/pdf | 419 KB
Download
NDS EZflow® and EZ-Drain™ Gravel-Free French Drain System Tech Spec
application/pdf | 382 KB
Frequently Asked Questions
The performance of each bead should be similar; the Transmissivity (flow through the system) will be similar, which will be one or two orders of magnitude greater than the native soils. EZ-Drain bead is smaller due to manufacturing considerations. EZ-Drain is available in smaller diameter bundles and the smaller bead assembles better. “EZflow” will be used throughout this document to describe both products.
EZflow drainage systems are designed for use in residential and light commercial non-traffic applications. EZflow drainage systems are designed to withstand single pass construction wheel loading and occasional light vehicular load of up to 16,000 lbs per axle provided the product is installed in a trench with 12" of compacted fill placed over the bundles. EZflow drainage systems are not designed to be placed under live-load traffic conditions such as paved or non-paved roadways, driveways, or parking areas.
Yes, simply maneuver the aggregate to either side of your cut, use two long zip ties to tourniquet the area to be cut and proceed with the cut.
EZflow’s Poly-Rock is an engineered aggregate that consists of hardened expandable polystyrene, an inert compound. Polystyrene does not absorb water, nor break down in water or other aqueous solutions.
Yes, EZflow can contribute to the accumulation of LEED credits for a project when used as part of the Stormwater design, or by contributing to the proportion of recycled materials used on site.
EZflow must be covered with a minimum of 6 inches of soil. The maximum depth to bury EZflow is 10 feet of soil. Please contact NDS Technical Services for depths exceeding 10 feet.
The bundles are fabricated with corrugated polyethylene internal piping. Pipe sizes are available in 3 in., 4 in. or 6 in. diameters. The EZflow couplers or commercially available fittings are used to allow other pipe types or sizes to be connected very easily. Internal coupling connections for all fittings are optimal.
Most clay soils are permeable, although at a significantly lower rate than granular soils. The ability of a subsurface drain to drain clay soils is a function of the clay soil’s permeability – i.e. the ability of the soil to transmit water to the drainage trench. Groundwater interceptor drains can work in these soils if designed properly. Groundwater interceptor drains in low permeable soil applications require a minimum of 4 in. of suitable fill material, coarse sand, placed above the drainage bundle and brought to grade. This can also be achieved with minimum of 2 in. of an overlying permeable strata, such as a low clay topsoil, mulch or decorative landscape stones over a minimum of 2 in of coarse sand. The interceptor drain should daylight to prevent saturation of the surrounding clay soils and to prevent the drain system from "bath tubbing."
A minimum of 2 in. of sand or pea gravel should be placed above the drainage bundle to provide a suitable base for the concrete. The basement drain lines should daylight to a sump or some other form of discharge.
Note: this is only for non-load bearing applications.
The mesh is not typically measured by its thickness but rather its unit weight as measured in ounces per square yard. ASTM D-3776 is a standardized test for measuring the weight. The unit weight of the geotextile mesh is 2.5 – 3.5 oz/sq. yd.
The EZflow Poly-Rock aggregate is made of 100% recycled resins. The product (aggregate, mesh and pipe) together would constitute a 90% percent minimum recycled content by weight (mass).
The pipe typically has a recycled content greater than 90%.
The polystyrene aggregate will tolerate extreme temperature ranges, and has a continuous use temperature range of -108°F to +175°F. It does not become brittle at subzero temperatures and does not need to be buried any deeper than for an installation in any other temperature range.
The AOS is a 30 U.S. Sieve (0.60 mm) for the geoxtextile mesh for the 7, 8, 10 and 15 inch products There are previously published specification that stated the 15 inch bundle mesh used was 70 U.S. Sieve. This is inaccurate and needs to be revised. All EZflow products are manufactured using a 30 U.S. Sieve geotextile mesh.
The product (aggregate, mesh and pipe) together would constitute a 90% percent minimum recycled content by weight (mass).
A basic rule of thumb is any 10 ft. section of any of the diameters can make a 180 degree radius (half circle). The pipe is the limiting factor in the product’s ability to contour. Any aggregate only bundle is capable of making very sharp bends such as 90 degree corners. The pipe bundles will require internal connection fittings to make bends of greater than 45 degrees.
The EZ-Drain aggregate bead (Poly-Rock) is manufactured with expanded polystyrene.
Note the following individual weights (per stick/section of EZflow or EZ-Drain):
- 7 in. agg – 2 lbs
- 7 in. pipe – 3.6 lbs
- 8 in. agg – 2.2 lbs
- 8 in. pipe – 4.9 lbs
- 10 in. agg – 2.7 lbs
- 10 in. pipe – 5.9 lbs
- 15 in. agg – 6.2 lbs
- 15 in. pipe – 13.0 lbs
EZflow is manufactured in 6 locations:
- Monticello, IL
- St. Augustine, FL
- Brevard, NC
- Garner, NC
- Portland, OR
- Duncanville, TX
Similar to mineral aggregate expanded polystyrene offers no nutritional value for insects or rodents and is therefore not a suitable environment for them. For this reason EPS has been widely used in building applications, inclusive of subsurface installations.
Root intrusion should be no more of a significant factor than in any other type of drainage system. The same "best design practices" should be employed for EZflow that are applied on other types of drainage systems. If roots are a concern then commercially available root inhibitors are available (from other manufacturers).
