Guide
Know what you're specifying.
The basics of liners, fabric, pipe and erosion control, and what to think about before you order. General guidance only: your project spec and engineer always come first.
Choosing a liner
Start with what it has to hold, whether it stays exposed and how the ground behaves. These are general comparisons; grades within a material vary.
PVC
Ponds, canals, landfill caps and stormwater, especially where it has to fit tight to the ground.
- Flexibility
- Very flexible
- Sun exposure
- Needs cover
- Chemical resistance
- Moderate
HDPE
Landfills, mining, chemical and large containment.
- Flexibility
- Stiff
- Sun exposure
- Good
- Chemical resistance
- Excellent
LLDPE
Caps, covers and lagoons on ground that may settle.
- Flexibility
- Flexible
- Sun exposure
- Good
- Chemical resistance
- Good
RPP
Exposed liners and floating covers.
- Flexibility
- Flexible, reinforced
- Sun exposure
- Excellent
- Chemical resistance
- Good
RPE
Farm ponds, canals, covers and temporary containment.
- Flexibility
- Flexible, reinforced
- Sun exposure
- Varies by grade
- Chemical resistance
- Good
EPDM
Decorative ponds and water features.
- Flexibility
- Very flexible
- Sun exposure
- Excellent
- Chemical resistance
- Limited
GCL
Composite liners and caps, under a geomembrane or soil.
- Flexibility
- Drapes with the ground
- Sun exposure
- Must be covered
- Chemical resistance
- Depends on the water and soil
A lined pond, layer by layer
Most lined ponds are built the same way, from the ground up. Your engineer's drawings set the details.
- 01
Shaped ground
Smooth and firm, with rocks, roots and standing water removed.
- 02
Drainage, if needed
Pipes or vents under the liner where groundwater or gas could lift it.
- 03
Cushion
A heavy nonwoven fabric that protects the liner from the ground.
- 04
Liner
The barrier itself, with its edges buried in an anchor trench at the top of the slope.
- 05
Cover
Soil, rock or nothing, depending on whether the liner is made to take the sun.
Florida conditions
Heat, sun, water and storms shape what works here. Worth thinking about before you choose a material.
- Sun and heat
- Strong sun breaks down liners and fabric that aren't made for it, and heat makes polyethylene liners grow and shrink through the day. Pipe pressure ratings drop as temperatures climb.
- High water table
- Groundwater sits close to the surface in much of the state. Water or gas building up under a liner can lift it, so many ponds need drainage or vents underneath.
- Sinkholes and limestone
- Karst ground can open beneath a pond. It's one of the main reasons a Florida pond gets a liner, and limestone water can weaken clay liners.
- Sandy soil
- Most stormwater ponds are built to soak into the sand, so many don't need a liner at all. Bare sand also erodes fast, so slopes need cover quickly.
- Storms
- Wind can lift exposed liners and covers that aren't ballasted, and material lead times stretch around hurricanes. Order early.
What geotextile does
Most fabrics do more than one job. Many state DOT specs are based on AASHTO M288, which sets survivability classes from Class 1, the harshest installation, to Class 3, the mildest. Florida DOT uses its own fabric types and approved product list.
- Separation
- Keeps stone from sinking into soft ground, and soil from working up into the stone.
- Filtration
- Lets water through while holding the soil back, in drains, behind walls and under riprap.
- Drainage
- Carries water along the fabric itself, usually as part of a drainage composite.
- Cushioning
- Protects a geomembrane from puncture by stone and rough ground.
- Stabilization
- Separates, filters and adds some strength on soft ground, under roads and working platforms.
- Reinforcement
- High-strength fabric or grid adds tensile strength to soil, for embankments, steep slopes and walls.
Erosion control life
Choose a product that outlasts the time grass needs to establish, then check its slope and channel ratings against the site. Exact categories vary by agency.
Ultra-short term
About 3 months
Straw blankets on gentle ground.
Short term
About 12 months
Straw blankets, with more netting as slopes steepen.
Extended term
About 24 months
Straw and coconut blends on longer, steeper slopes.
Long term
About 36 months
Coconut fiber where grass is slow to establish.
Permanent
Beyond 3 years
Turf reinforcement mats in channels and on steep slopes.
Turbidity barriers
Floating barriers are chosen by how rough the water is; your permit may name a type. Staked barriers suit shallow water and shorelines. In Florida, barriers must also be placed so they don't trap manatees.
Type I
Light duty. Calm, sheltered water with little or no current, wind or waves.
Type II
Moderate duty. Some current, under about 3.5 feet per second, and some wind.
Type III
Heavy duty. Current of about 3.5 to 5 feet per second, with moderate wind and waves. Not for open surf.
HDPE pipe ratings
Lower DR means a thicker wall and a higher pressure rating. These are standard ratings for PE4710 in water service.
| Dimension ratio | Pressure rating |
|---|---|
| DR 7 | 335 psi |
| DR 9 | 250 psi |
| DR 11 | 200 psi |
| DR 13.5 | 160 psi |
| DR 15.5 | 138 psi |
| DR 17 | 125 psi |
| DR 19 | 110 psi |
| DR 21 | 100 psi |
| DR 26 | 80 psi |
| DR 32.5 | 63 psi |
Ratings are for water at up to about 80°F. They drop at higher temperatures, and the engineer sets the design.
On site
General good practice. The manufacturer's instructions and your project spec take priority.
- Store it right
- Keep rolls clean, dry and flat, out of direct sun, and stacked no higher than the manufacturer allows. Clay liners must stay dry until they're covered, and most fabrics aren't meant for long sun exposure either.
- Prepare the ground
- Smooth, firm subgrade, with roots, sharp rocks, standing water and debris removed. A heavy nonwoven cushion helps where the ground can't be made smooth.
- Anchor the edges
- Run the liner into an anchor trench at the top of the slope, with rounded corners and no sharp bends. Polyethylene liners grow and shrink with heat, so backfill them in the cool part of the day, after the sheet has settled.
- Allow for extra
- Order for slopes, anchor runs, seam overlap and waste, not just the footprint. Send us the dimensions and we'll work out a first number.
- Order by spec, not by weight
- Fabric weight is only a rough guide. Specs set strength, puncture resistance, flow rate and opening size. Send us the spec and we'll match those, not just the ounces.
- Overlap fabric the right way
- Lap fabric at least a foot in drains, and more under riprap and on soft ground. On slopes, lay the upper sheet over the lower one so water runs over the lap, not into it.
- Silt fence goes on the contour
- Run it level across the slope, bury the bottom edge and set the posts on the downhill side. Keep it out of ditches and streams, and clean it out when sediment reaches about half its height.
- Size the turbidity skirt
- The skirt should hang close to the bottom without dragging in the mud. Anchor the barrier at both ends and along its length, never from the skirt, and leave it until the water clears.
What to send us
Rough numbers are fine. The more of this we have, the faster and sharper the quote.
Every job
- Where the job is, and when you need material on site
- Supply only, or supply with installation or repair in Florida
- What it has to hold or do: water, wastewater, chemicals, soil or sediment
- Size: length, width, depth and side slope, or total area
- Drawings, the spec section and photos, if you have them
- Whether the job is DOT, permit or federally funded, and what paperwork you need
Liners and covers
- Material and thickness, if the spec names one
- Exposed to the sun, or covered with soil
- Pipes or posts coming through the liner: size and count
- Panels or rolls, and who unloads the truck
HDPE pipe
- What it carries, at what pressure and temperature
- Size system (IPS, DIPS or CTS), size and DR
- Total length, sticks or coils, and a list of fittings
- Drinking water or not, and trenched or drilled
Common questions
Don't see yours? Ask us.
Liners
What liner thickness do I need?
It depends on the material, the ground and what's being held. For many ponds in PVC, 30 mil is the most common choice. Send us the job and we'll match the thickness to it.
Does every stormwater pond need a liner?
No. Most Florida stormwater ponds are meant to let water soak into the ground. A liner is used when the pond has to hold water, for example over sinkhole-prone ground, near contamination, or when water is stored for irrigation. The project engineer and the permit decide, and we supply to what they call for.
What's the difference between PVC and HDPE?
PVC is soft and flexible. It fits tight to the ground, comes in big factory panels and is usually buried under soil. HDPE is stiff and tough, stands up to sun and harsh chemicals, and is welded together on site. Ponds and canals often use PVC; landfills, mining and chemical work usually use HDPE.
What is a composite liner?
A geomembrane laid directly on compacted clay or a clay liner. If one layer gets a small hole, the other slows the leak. Landfills and other regulated sites often require one.
Can a liner be left exposed to the sun?
Some can. HDPE, LLDPE, EPDM and reinforced liners rated for exposure handle the sun well. Standard PVC and clay liners need to be buried under soil. Even a sun-rated liner generally lasts longer covered.
How long will a liner last?
It depends on the material, sun exposure, temperature and what it's holding. Buried liners generally last much longer than exposed ones. We'll help you pick a material for the service life you need.
Will it stand up to the chemicals I'm storing?
That depends on the chemical, its concentration and temperature. Tell us all three and we'll check the material against the manufacturer's chemical resistance data. For critical or regulated containment, the engineer of record makes the final call.
Is a liner safe for drinking water or fish?
Only some are. Materials in contact with drinking water need certification for that use. For fish and shrimp ponds, ask for the material's documentation before you order, and we'll send what the manufacturer provides.
Will roots grow through a liner?
Liners resist roots, but they aren't immune, and thin ones are more at risk from aggressive plants. Clear roots and organic material from the ground before the liner goes down.
Will the liner work for an NRCS cost-share pond?
Ponds built with NRCS help have to meet the agency's lining standard, which sets minimum thicknesses and cover. Send us the NRCS design and we'll match the material to it.
Can I install it myself?
On smaller jobs, often yes. Seaming is specialized work, though, and many manufacturer warranties depend on a qualified installer, so check the terms first. In Florida, we install through experienced partner crews.
Fabric and erosion control
What's the difference between woven and nonwoven fabric?
Woven fabric is strong and stiff, good for separating and reinforcing under stone. Nonwoven is felt-like, lets water through easily and cushions, good for drains, filters and under liners. Many jobs use both.
Which turbidity barrier type do I need?
It depends on the current, wind and waves at the site, and your permit may name a type. Tell us the water body, its depth and how fast it moves, and we'll recommend one.
Do I need a stormwater permit?
In Florida, construction that disturbs an acre or more, or is part of a larger plan that will, generally needs coverage under the state's construction stormwater permit and a pollution prevention plan. The site operator holds the permit; we supply the erosion and sediment control materials it calls for.
Can you match a DOT or project spec?
Send us the spec section and your state. We'll match the material to the requirements and source it from the state's approved product list where one applies.
HDPE pipe
What do DR and SDR mean?
DR is the pipe's outside diameter divided by its minimum wall thickness, so a lower number means a thicker wall and a higher pressure rating. SDR is a DR from the standard preferred series.
What do IPS, DIPS and CTS mean?
They are size systems. IPS matches steel pipe outside diameters, DIPS matches ductile iron, and CTS matches copper tubing for small service lines. A 6-inch IPS pipe and a 6-inch DIPS pipe are different sizes, so tell us which you need.
What's the difference between PE4710 and PE3608?
Both are high-density polyethylene. PE4710 is the newer, higher-rated grade, so at the same DR it carries about a quarter more pressure. Many specs now call for it.
Does hot weather change a pipe's pressure rating?
Yes. Published ratings hold up to about 80°F. Warmer water, or pipe sitting in the Florida sun, lowers the safe working pressure. Tell us the operating temperature so the wall can be sized for it.
Can I use corrugated pipe for a pressure line?
No. Corrugated pipe is for gravity drainage, such as storm drains and underdrains. Pressure lines use solid-wall pipe joined by fusion or rated fittings.
Why fuse HDPE pipe instead of using gasket joints?
Fusion joins the pipe into one continuous, fully restrained line. Done to the industry joining procedure, the joint is as strong as the pipe, with no gaskets to leak or pull apart.
Ordering
Why are some products priced by the square foot and others by the square yard?
That's how the trade sells them: liners usually by the square foot, fabric by the square yard. One square yard is nine square feet, and our quote shows the units clearly.
Do you offer an "or equal" product?
Often, yes. We can offer a product with matching properties and send its data for review. The engineer decides whether it's accepted.
What paperwork can you provide?
Tell us the spec section and what your engineer needs to see, and we'll provide the product documentation for review.
What warranty comes with the material?
Material warranties come from the manufacturer, and many depend on proper storage and a qualified installer. We'll pass the terms on with your quote.
How does material ship, and who unloads it?
Most orders come on a flatbed or box truck. Rolls are heavy, so plan a forklift or loader with the right lifting bar or straps. Tell us what equipment you'll have and whether a full-size truck can reach the site.
Can I get material quickly around a hurricane?
Demand jumps around storms, so order as early as you can. We'll give you the lead time we get from the manufacturer, not a guess.
Glossary
Words you'll see on specs, drawings and quotes.
- Mil
- A thousandth of an inch. Liner thickness is measured in mils, so 30 mil is 0.030 inch.
- Geomembrane
- A plastic or rubber sheet that acts as a barrier to liquid or gas.
- GCL
- Geosynthetic clay liner: a layer of bentonite clay held between two fabrics.
- Geotextile
- A fabric that separates, filters, drains, cushions or reinforces soil.
- Smooth and textured
- Textured sheet has a rough surface that grips the soil on slopes; smooth sheet doesn't.
- Reinforced
- A liner with a woven scrim inside for strength and tear resistance.
- Subgrade
- The prepared ground the liner or fabric is laid on.
- Anchor trench
- A trench at the top of a slope where the liner edge is buried to hold it in place.
- Panel
- A large sheet made by joining rolls in a factory before it ships.
- Pipe boot
- A sleeve that seals a liner around a pipe passing through it.
- Composite liner
- A geomembrane on top of compacted clay or a GCL, working together.
- Double liner
- Two liners with a drainage layer between them that catches and shows any leak.
- oz/sy
- Ounces per square yard: the weight of a fabric, a rough guide to its strength.
- AOS
- Apparent opening size: roughly the size of the largest openings in a fabric.
- DR
- Dimension ratio: a pipe's outside diameter divided by its wall thickness.
- Spec section
- The part of the project specifications that sets the requirements for a material.
- Submittal
- The product documents sent to the engineer for approval before material is used.
- SWPPP
- Stormwater pollution prevention plan: the erosion and sediment plan for a construction site.