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Retaining Wall Separation Fabric - 4' x 100' - 4.5 oz

Retaining Wall Separation Fabric - 4' x 100' - 4.5 oz

SKU FNW4.504100
$280.21 - $280.21
$280.21
$280.21 - $280.21
$280.21
Free Shipping

Separation · 4.5 oz Non-Woven · 4′ × 100′

Retaining Wall Separation Fabric on a 4′ × 100′ roll covering 400 square feet. A 4-foot height in the heavier non-woven, for coarser stone. A 4.5 oz non-woven geotextile for separating soil from aggregate. Flow passes through the body of the fabric in every direction, and the heavier weight adds puncture resistance for coarse angular stone.

Roll Size
4′ × 100′400 sq ft per roll
Part Number
FNW4.504100Geotextile
Weight
4.5 ozNon-woven, needle-punched
Position
Between layersSoil and aggregate
  • Separates soil from aggregate
  • Flow through the fabric body
  • For coarse angular stone
  • Will not rot or decay
  • Free shipping on all orders

Free Shipping - Please submit a Quote Request for quantities larger than listed below.

Quantity Price Per Unit
(Free Shipping)
1 $280.21
2+ $266.20
3+ $252.19
10+ $238.18

01 Three fabrics · one wall

Retaining Wall Fabric

A single retaining wall build uses geotextile in more than one place, and the fabric is not the same in each. It goes under the base so the wall does not settle, and it goes behind the face so the drainage stone does not silt up — two positions in the same project, with different demands on the material.

Using one fabric everywhere is where wall problems start, because a fabric that is good under compaction is not the one that passes water best. This page covers the three retaining wall fabrics we stock and where each belongs in the build.

3fabrics in one wall

Support under the base, then filtration or separation behind the face — different positions, different fabrics.

02 Why a wall fails

It Is Almost Never The Blocks

Walls move because the ground beneath them settles unevenly, because water builds up behind them when the drainage stone silts up, or because base and subgrade have mixed until the base is no longer a base. All three are fabric problems, and all three are cheap to prevent and expensive to fix.

03 Which goes where

Support, Filtration And Separation

FabricConstructionPositionWhat it does
Support200 lb slit film wovenUnder the base courseSupports the wall base.
Stops the leveling pad settling into the subgrade, and reduces the base material needed.
Filtration3 oz spunbond wovenBehind the wall faceFilters the backfill.
Lets water reach the drain while holding back the fines that would clog the drainage stone.
Separation4.5 oz non-wovenBetween soil and aggregateSeparates soil from stone.
High flow through the fabric body, keeping backfill and drainage stone from mixing.
A typical build uses two. Support fabric under the leveling pad, and either filtration or separation behind the face — which of those depends on how much water the wall has to shed and how fine the retained soil is. On a tall wall or wet ground, all three.

04 Under the base

Retaining Wall Support Fabric

A woven geotextile with excellent puncture and tear resistant strength, rated at 200 lb. Its job is soil separation over moderate subgrades beneath the leveling pad — keeping the compacted base and the subgrade from mixing so the pad the wall sits on stays flat and stays at its designed thickness.

It also means less base material, because a separated base holds its effective depth instead of thinning every season. Four sizes, sized for wall runs rather than open ground.

4′ × 50′200 sq ft 4′ × 100′400 sq ft 6′ × 50′300 sq ft 6′ × 100′600 sq ft

05 Behind the face

Retaining Wall Filtration Fabric

A 3 oz spunbond polypropylene geotextile with high puncture resistance. Spunbond construction gives high water flow and excellent permittivity, which is exactly what the back of a wall needs: water has to get to the drain, and the fines that come with it must not.

This is the fabric between the retained soil and the drainage stone. Get it wrong and the stone silts up, water backs up behind the wall, and the wall starts taking a load it was never designed for.

3′ × 100′300 sq ft 4′ × 100′400 sq ft 6′ × 100′600 sq ft 8′ × 100′800 sq ft
The 8′ width is worth noting: it lets a taller wall face be lined in a single height with no horizontal seam, and a horizontal seam behind a wall is precisely where soil finds its way into the stone.

06 Between the layers

Retaining Wall Separation Fabric

A 4.5 oz non-woven geotextile made from polypropylene staple fibers that will not rot or decay. Non-woven construction passes water through the body of the fabric in every direction rather than only along a weave, which makes it the stronger choice where drainage matters as much as separation.

It is the heavier of the two back-of-wall options, with more puncture resistance for coarse angular drainage stone and more cushioning over uneven excavation.

3′ × 100′300 sq ft 4′ × 100′400 sq ft 6′ × 100′600 sq ft
Filtration or separation behind the face? The 3 oz woven filtration fabric suits most walls in reasonable soil. Step up to the 4.5 oz non-woven where the drainage stone is coarse and angular, where the retained soil is fine and wet, or where the wall is tall enough that a failure would be serious.

07 Installation

Where Each Fabric Goes

Support fabric goes down first, on the graded subgrade, before the leveling pad aggregate. Overlap adjacent runs and carry it far enough forward and back that the whole pad sits on fabric rather than half on and half off.

Filtration or separation fabric lines the excavated face and the base of the drainage zone before the stone goes in. Place the stone against it, then backfill.

Overlap generously and never butt the joints, on any of the three. A separation or filter layer only works where it is continuous, and a joint that opens under load is a direct path for soil into the stone.

The top edge is where wall installations fail. If the fabric behind the face stops below the level of the backfill, soil washes straight over the top into the drainage stone and everything below it makes no difference at all. Carry it up and fold it over.

08 You will also need

6″ Landscape Staples

Fabric that shifts while you are placing stone leaves gaps in the layer exactly where you cannot see them once the wall is up. Pin the edges and every overlap before backfilling.

6″ landscape staples are the standard pin for these fabrics, and they are sold separately — worth adding to the order rather than discovering the gap on install day.

View 6″ Landscape Staples

09 Buying from us

Why Buy Retaining Wall Fabric From Landscape Discount

All three fabrics stocked

Support, filtration and separation, so the wall gets the right fabric in each position rather than one fabric stretched across all of them.

Sizes built for wall runs

50 and 100-foot rolls in 3′ to 8′ widths, so you are not buying a 300-foot roll to line one wall.

Commercial grade only

Professional-grade geotextile throughout. We never substitute another fabric or weight without the explicit consent of the customer.

We answer the phone

When you call you quickly reach a helpful, live person happy to answer your product and order questions. (M-F 5:00 am - 3:00 pm Pacific Time)

10 Common questions

Retaining Wall Fabric FAQs

Which fabrics does my wall need?
Usually two. Support fabric goes under the leveling pad to stop the base settling into the subgrade, and either filtration or separation fabric goes behind the wall face to keep soil out of the drainage stone. A tall wall on wet ground uses all three.
Filtration or separation behind the face?
The 3 oz woven filtration fabric suits most walls in reasonable soil. Step up to the 4.5 oz non-woven separation fabric where the drainage stone is coarse and angular, where the retained soil is fine and wet, or where the wall is tall enough that a failure would be serious.
Can I use one fabric throughout?
You can, and it is where most wall problems begin. The base wants a high-tensile woven fabric that resists puncture under compaction; the back of the wall wants high flow through the fabric. Those are different properties, and no single fabric is best at both.
How much do I need?
Work out the wall face area and the leveling pad area separately. Rolls run from 200 up to 800 sq ft, in 50 and 100-foot lengths, so most walls are covered without buying into a long roll. Allow extra for overlaps.
What width should I use behind the face?
Enough to cover the full height of the drainage zone in one piece and still fold over at the top. The 8′ filtration roll exists for exactly that on taller walls, because a horizontal seam behind a wall is where soil gets into the stone.
Do I overlap or butt the seams?
Always overlap, on all three fabrics. A separation or filter layer only works where it is continuous, and a joint that opens under load is a direct path for soil into the drainage stone.
What is the most common installation mistake?
Stopping the fabric below the level of the backfill. Soil then washes over the top edge into the drainage stone, and every bit of fabric below it makes no difference. Carry it up and fold it over.
Does the support fabric really save on base material?
Yes. A separated base holds its effective thickness instead of thinning as fines pump up and stone punches down, so a thinner base does the job a thicker one would otherwise have needed.
How do I secure the fabric?
Pin the edges and every overlap before backfilling. 6″ landscape staples are the standard pin for these fabrics and are sold separately.
What does shipping cost?
Nothing. Shipping is free on every order, at any quantity.