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Geocomposite Drain Spec Finder
Enter the minimum performance your project requires and we'll find the right American Wick Drain SITEDRAIN geocomposite.
Filter by Specs
Set by burial depth & soil / surcharge loads. Available: 6,000–30,000 psf
Drainage capacity along the core. Tested at a different gradient by type — pick a drain type to compare
Available: 100–240 lbs
Smaller = finer filtration. Fabrics are published at these two sizes
Available: 2.1–2.7 sec⁻¹
Available: 305–800 lbs
Woven fabrics aren't M288-graded, so they're shown as N/A. Nonwovens with no published class won't match
Use the Spec Finder above
Specifying a geocomposite drain is a numbers exercise: burial depth sets the compressive strength you need, expected water volume sets the in-plane flow, and the surrounding soil sets the filter fabric. The Geocomposite Drain Spec Finder at the top of this page lets you enter the minimum performance your project requires — by ASTM property — and screens the full American Wick Drain SITEDRAIN line for products that meet or beat every threshold. This guide explains what each of those numbers means so the match you get is the right one.
What Is a Geocomposite Drain?
A geocomposite drain — also called a prefabricated drainage composite, drainage composite, or sheet drain — is a manufactured drainage product that bonds two or three materials into one roll or panel: a molded plastic drainage core (typically a dimpled HDPE sheet or a high-flow geonet) that creates open space for water to move, and a geotextile filter fabric heat-bonded to one or both faces that lets water in while holding soil back. Some products add an impermeable backing so water is collected on one side only.
The result is a thin, high-capacity drainage layer that does the job of a traditional aggregate-and-pipe system in a fraction of the thickness. Because the core and filter arrive pre-assembled, a geocomposite installs faster than hauling, placing, and wrapping stone — which is why it's the go-to French drain alternative against foundations, behind retaining walls, and under plaza decks. American Wick Drain's SITEDRAIN line is the family this finder draws from.
The Five Geocomposite Drain Types
The finder's first filter is drain type, because form follows the surface you're draining. Match the type to the geometry of your job:
Single-Sided Sheet
Collects water from one face, with filter fabric on the drainage side and a solid backing on the other. The standard for walls where you want water pulled off the structure and nothing entering from behind — foundation walls, retaining walls, planters.
Double-Sided Sheet
Collects from both faces, with filter fabric bonded to each side. Used where water needs to enter from two directions — between soil layers, under slabs, or in landfill and cap applications.
Chimney (Column) Drain
A narrow vertical strip that intercepts seepage on a wall and channels it down to a collector — the geocomposite equivalent of a chimney drain in an earth structure. Efficient where a full sheet isn't needed.
Strip Drain
A compact core-and-wrap strip that serves as a pipe-and-stone alternative in trenches, behind walls, and along footings. Rolls out fast and conforms to the trench.
Combination (High Strength + High Flow)
Pairs a heavy-duty core with a high-transmissivity design for jobs that demand both deep-burial compressive strength and serious drainage capacity — deep foundations, structural fills, and heavily surcharged walls.
Decoding the ASTM Specs
Every threshold in the finder maps to a published ASTM (or AASHTO) test method. Here's what each one controls and how to set it:
| Spec | Test Method | What It Controls | How to Set It |
|---|---|---|---|
| Compressive Strength (psf) | ASTM D6364 | Load the core carries before it crushes and loses flow | From burial depth plus soil and surcharge (traffic, structure) loads |
| In-Plane Flow / Transmissivity (gpm/ft) | ASTM D4716 | How much water the core can carry along its length | From expected water volume and hydraulic gradient |
| Grab Tensile (lbs) | ASTM D4632 | Fabric's resistance to tearing during install and backfill | Higher for rough backfill and deep placement |
| Apparent Opening Size (AOS) (mm) | ASTM D4751 | Largest soil particle the filter passes — smaller = finer filtration | Set a MAX based on soil gradation; fine soils need a smaller AOS |
| Permittivity (sec⁻¹) | ASTM D4491 | Rate water flows through the fabric (cross-plane) | Higher for high-flow, high-permeability soils |
| CBR Puncture (lbs) | ASTM D6241 | Fabric's resistance to puncture from stone and debris | Higher for angular backfill and demanding sites |
Geotextile Filter: Nonwoven vs. Woven
The filter fabric bonded to the core is what keeps soil out of the flow path, and the finder lets you require a fabric family:
- Nonwoven needle-punched (NPNW) — the most common drainage filter. High permittivity and flow, good elongation to conform over rough surfaces, and it carries an AASHTO M288 survivability class. The default for most foundation and wall work.
- Woven monofilament — a dimensionally stable filter with precise opening sizes, used where high strength and a specific AOS matter more than maximum flow. Woven fabrics do not carry an M288 class.
Where Geocomposite Drains Are Used
Foundation drainage
A single-sided sheet against the foundation wall relieves hydrostatic pressure and carries groundwater down to the footing drain — a thinner, faster foundation drainage board in place of stone backfill.
Retaining wall drainage
Behind segmental, cast, or MSE walls, a sheet or strip drain intercepts water before it builds pressure against the wall — the core of proper retaining wall drainage design.
Plaza decks & planters
Double-sided sheets drain waterproofed structural slabs and planter boxes over occupied space, protecting the membrane and the structure below.
Landfills & civil works
High-flow geonet composites serve as leachate collection and cap drainage layers where transmissivity and chemical durability are critical.
Installation Basics
01Prep the Surface
Confirm any waterproofing or wall membrane is cured and sound. The geocomposite protects it — it doesn't replace it.
02Orient the Fabric
Face the filter fabric toward the soil (the water source). On single-sided sheets, the solid backing goes against the wall.
03Fasten & Overlap
Attach at the top and shingle-overlap seams so water sheds downward. Lap the fabric flap over the adjacent core per the manufacturer's detail.
04Connect & Backfill
Tie the base into a footing drain or collector, then backfill carefully to avoid displacing or puncturing the panel.
Shop Geocomposite Drains
Sheet Drains
Single- and double-sided SITEDRAIN sheets for foundations, walls, and plaza decks.
Shop Sheet Drains →
Strip & Chimney Drains
Compact core-and-wrap strips — a fast pipe-and-stone alternative for trenches and walls.
Shop Strip Drains →
High-Strength Composites
Combination cores for deep burial and high-flow structural drainage.
Shop Composites →
Geocomposite Drain FAQ
What is a geocomposite drain?
A geocomposite drain is a prefabricated drainage product that bonds a molded plastic drainage core to a geotextile filter fabric. The core creates open space for water to flow while the fabric lets water in and keeps soil out. It provides high-capacity drainage in a thin profile and commonly replaces aggregate-and-pipe systems against foundations and retaining walls.
What is the geocomposite drainage layer for?
The drainage layer collects water at a surface — a foundation wall, retaining wall, slab, or planter — and carries it away before it can build hydrostatic pressure or saturate the soil. It relieves water pressure on structures and protects waterproofing membranes.
How do I choose the right compressive strength (ASTM D6364)?
Base it on how deep the drain is buried plus any loads above it. The soil column and any surcharge from traffic or structures press on the core, and if that load exceeds the core's rating it compresses and loses flow capacity. Deeper burial and heavier surcharge require a higher minimum compressive strength. Enter that minimum in the finder and it excludes any product that can't carry it.
What is in-plane flow (ASTM D4716) and why does it matter?
In-plane flow, or transmissivity, is how much water the core can carry along its own plane toward the outlet. It's the drainage capacity of the product. Set the minimum from your expected water volume and slope; higher flow is needed for wet sites, long runs, and shallow gradients.
Do I need a nonwoven or woven geotextile filter?
Nonwoven needle-punched (NPNW) fabric is the usual choice for drainage — high flow, good conformance, and it carries an AASHTO M288 survivability class. Woven monofilament is chosen where you need a precise opening size and high strength more than maximum flow. Woven fabrics do not carry an M288 class, so requiring a class in the finder narrows results to nonwovens.
Can a geocomposite replace a French drain or pipe and stone?
In most foundation and retaining-wall situations, yes. A geocomposite drain delivers comparable or greater drainage capacity in a much thinner profile and installs faster because the core and filter arrive pre-assembled — no hauling, placing, and wrapping aggregate. A strip drain in particular is a direct pipe-and-stone alternative. Confirm the compressive strength and flow meet your project's requirements.