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Pond Underlay Fabric

Non-Woven · 3 Weights · 8 Rolls

Dewitt Protective
Pond Underlayment

Goes Under The Liner.

Shields the pond liner from sharp objects and abrasive materials while supporting it over soft areas. Two sizes folded to 6′ for easier handling.

  • Protects the liner from rock and ridges
  • Supports the liner over soft areas
  • Two sizes folded to 6′
Shop pond underlayment
  • 3Weights
  • 8Roll sizes
  • 2Folded to 6′

DeWitt Landscape Fabric

Pond Underlayment

Pond underlay fabric is installed beneath the waterproof pond liner, forming a barrier between the liner and anything sharp or abrasive below it — rocks, gravel, ridges. It gives a smooth, stable surface that supports the liner rather than letting it bridge over hard points.

The liner carries the enormous volume of water sitting above it, and that load concentrates wherever the ground beneath is uneven. Every rock and ridge becomes a stress point, and underlayment removes them.

It also replaces something that does not work. Cardboard, sand, old carpet padding and newspaper all rot away, fall apart or tear — and when they go, the liner is left sitting on the rocks they were covering, under the full weight of the water.

Dewitt Protective Pond Underlayment Folded to 6' - 4 oz.(12' x 100')
$726.70 - $726.70
$726.70
$726.70 - $726.70
$726.70

Dewitt Protective Pond Underlayment Folded to 6' - 4 oz.(12' x 100')

Dewitt · Pond Underlayment · 4 oz · Folded To 6′ Dewitt 4 oz protective pond underlayment on a 12′ × 100′ roll covering 1,200 sq...

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$726.70 - $726.70
$726.70
$726.70 - $726.70
$726.70
Dewitt Protective Pond Underlayment Folded to 6' - 6 oz.(12.5' x 100')
$800.61 - $800.61
$800.61
$800.61 - $800.61
$800.61

Dewitt Protective Pond Underlayment Folded to 6' - 6 oz.(12.5' x 100')

Dewitt · Pond Underlayment · 6 oz · Folded To 6′ Dewitt 6 oz protective pond underlayment on a 12.5′ × 100′ roll covering 1,250 ...

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$800.61 - $800.61
$800.61
$800.61 - $800.61
$800.61
Dewitt Protective Pond Underlayment - 8 oz.(7.5' x 300')
$1,600.08 - $1,600.08
$1,600.08
$1,600.08 - $1,600.08
$1,600.08

Dewitt Protective Pond Underlayment - 8 oz.(7.5' x 300')

Dewitt · Pond Underlayment · 8 oz Dewitt 8 oz protective pond underlayment on a 7.5′ × 300′ roll covering 2,250 square feet. A n...

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$1,600.08 - $1,600.08
$1,600.08
$1,600.08 - $1,600.08
$1,600.08
Pond liner fabric Dewitt
$1,884.57 - $1,884.57
$1,884.57
$1,884.57 - $1,884.57
$1,884.57

Dewitt Protective Pond Underlayment - 4 oz.(12.5' x 360')

Dewitt · Pond Underlayment · 4 oz Dewitt 4 oz protective pond underlayment on a 12.5′ × 360′ roll covering 4,500 square feet. A ...

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$1,884.57 - $1,884.57
$1,884.57
$1,884.57 - $1,884.57
$1,884.57
Dewitt Protective Pond Underlayment - 4 oz.(15' x 300')
$1,934.40 - $1,934.40
$1,934.40
$1,934.40 - $1,934.40
$1,934.40

Dewitt Protective Pond Underlayment - 4 oz.(15' x 300')

Dewitt · Pond Underlayment · 4 oz Dewitt 4 oz protective pond underlayment on a 15′ × 300′ roll covering 4,500 square feet. A wi...

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$1,934.40 - $1,934.40
$1,934.40
$1,934.40 - $1,934.40
$1,934.40
Dewitt Protective Pond Underlayment
$2,280.66 - $2,280.66
$2,280.66
$2,280.66 - $2,280.66
$2,280.66

Dewitt Protective Pond Underlayment - 6 oz.(12.5' x 360')

Dewitt · Pond Underlayment · 6 oz Dewitt 6 oz protective pond underlayment on a 12.5′ × 360′ roll covering 4,500 square feet. A ...

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$2,280.66 - $2,280.66
$2,280.66
$2,280.66 - $2,280.66
$2,280.66
Dewitt Protective Pond Underlayment - 8 oz.(15' x 300')
$2,317.55 - $2,317.55
$2,317.55
$2,317.55 - $2,317.55
$2,317.55

Dewitt Protective Pond Underlayment - 8 oz.(15' x 300')

Dewitt · Pond Underlayment · 8 oz Dewitt 8 oz protective pond underlayment on a 15′ × 300′ roll covering 4,500 square feet. The ...

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$2,317.55 - $2,317.55
$2,317.55
$2,317.55 - $2,317.55
$2,317.55
Dewitt Protective Pond Underlayment - 6 oz.(15' x 300')
$2,480.66 - $2,480.66
$2,480.66
$2,480.66 - $2,480.66
$2,480.66

Dewitt Protective Pond Underlayment - 6 oz.(15' x 300')

Dewitt · Pond Underlayment · 6 oz Dewitt 6 oz protective pond underlayment on a 15′ × 300′ roll covering 4,500 square feet. A wi...

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$2,480.66 - $2,480.66
$2,480.66
$2,480.66 - $2,480.66
$2,480.66

Choosing

Available Options

Pick the option that matches the job. Every product here is the same fabric within its line — only the size or weight changes.

4 oz3 rolls 6 oz3 rolls 8 oz2 rolls

Where Pond Underlayment Sits In The DeWitt Range

Seven DeWitt fabrics, and the first question is always the same: is the fabric going to live at the surface, or be buried? Woven fabrics belong at the surface; non-woven fabrics belong underground.

FabricConstructionWeightPositionJob
Sunbelt Ground CoverWoven3.2 ozSurfaceGeneral purpose weed control and water conservation
Ultraweb 3000Woven2.2 ozSurfaceCost effective cover with the highest UV protection
White Ground CoverWoven3.2 ozSurfaceReflective white, and doubles as a frost blanket
Pro 5 & 20 Year Weed BarrierWoven, needle-punched4.1 & 5 ozSurfaceHeavy-duty weed barrier under mulch, rock and soil
Non-Woven GeotextileNon-woven4, 4.5, 8 ozBuriedDrainage, filtration, separation and cushioning
Soil Filter FabricNon-woven3.1–6 ozBuriedBehind retaining walls and wrapping drainage pipe
Pond UnderlaymentNon-woven4, 6, 8 ozBuriedProtecting pond liners from sharp objects

Not sure which applies? The DeWitt landscape fabric hub walks through all seven by what the fabric has to do, with the full comparison in one place.

DeWitt Fabric Hub

Pond Underlayment Questions

Does it go above or below the liner?

Below. The order is excavation, underlayment, waterproof liner, then water.

Can I use sand, carpet or cardboard instead?

Those materials rot, fall apart or tear, and it is the most common reason ponds need repairing a few seasons later. When they fail the liner ends up sitting on the rocks they were covering, under the full weight of the water.

Which weight do I need?

4 oz where the excavation is reasonably smooth soil. 6 oz where there is some rock or coarse material, or on a larger pond. 8 oz for rocky, gravelly or uneven ground and deeper installations.

What does “folded to 6 feet” mean?

The roll is folded so it handles at 6 feet wide rather than its full width, which makes carrying and positioning considerably easier on a smaller pond.

What does shipping cost?

Nothing. Shipping is free on every order, at any quantity.