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ARMORTHANE PROTECTING YOUR WORLD

PROTECTING YOUR WORLD

ARMORTHANE PROTECTING YOUR WORLD

Spray-On Rubber
Coating: Aerosol
to Polyurea

Flex Seal-style cans, peel-off dips, undercoating, liquid rubber and sprayed polyurea all get called spray-on rubber. We make the professional kind. Here’s what each one is, how thick it builds, how long it lasts and what it costs.
Spray-On Coatings

Need a coating that outlasts the can? Talk to a certified polyurea applicator.

Tell us what you're coating and roughly how big it is. We'll connect you with an ArmorThane-certified applicator who will quote the product, the thickness in mils and the surface prep in writing.

  • Truck beds, trailers and equipment
  • Roofs, decks, ponds and water features
  • Tanks, containment and drinking-water linings
  • Contractors: ask about polyurea rigs and training
Rather talk now? Call (417) 831-5090
Step 1 of 3
≈12 sq ft
Per 14 oz aerosol can
Flex Seal’s stated coverage
10–12 mils
A peel-off dip done right
Plasti Dip: 4–5 spray coats
40–60%
Asphalt in one “liquid rubber”
Per the product’s own SDS
60–125 mils
Sprayed polyurea build
ArmorThane published data

Type “spray on rubber coating” into a search bar and you’ll get aerosol cans, peel-off wheel dip, undercoating, five-gallon pails of roof sealer and truck bedliners. They all dry to something that feels like rubber. That’s about all they have in common.

Quick answer

“Spray-on rubber” is at least five different products. Aerosol rubber sealants (Flex Seal type) patch small leaks above the waterline. Peel-off synthetic rubber dips (Plasti Dip) build about 10–12 mils for grips, trim and wheels. Rubberized undercoating protects a chassis for a few years. Pails of “liquid rubber” (the one we checked is 40–60% asphalt cement) seal roofs and foundations. And sprayed polyurea, applied by a pro at 60–125 mils, is what goes in truck beds, ponds, tanks and on roofs that have to last decades. Pick by the job, not the label. Jump to the product picker or the cost planner.

Most pages on this search are store listings. They’ll tell you a can covers “up to 12 square feet.” They won’t tell you how thick that is, whether it can sit under water, or what happens when you drive on it.

We manufacture polyurea and polyurethane spray elastomers in Springfield, Missouri, and have for 35+ years. That’s the professional end of “spray-on rubber.” So this guide is honest about both ends: where a $15 can is exactly the right answer, where it isn’t, and when it’s worth calling an applicator.

What’s in this guide
  1. 1What spray on rubber coating actually is
  2. 2Does it really work?
  3. 3Which one fits your job (picker)
  4. 4How thick it builds (mils converter)
  5. 5How long it lasts
  6. 6Cost, cans and dry time (planner)
  7. 7By surface: metal, wood, concrete, roofs, cars, ponds
  8. 8How to apply it so it sticks
  9. 9When to hire a polyurea applicator
  10. 10Sprayed polyurea, the professional version
  11. 11Spray on rubber FAQ
Decode the label

What is spray on rubber coating? Five different products

Spray on rubber coating is any liquid that’s sprayed (or brushed) on and dries or cures into a flexible, rubber-like film. The chemistry underneath varies a lot: rubber resins in aerosol cans, peelable synthetic rubber, asphalt emulsions sold as “liquid rubber,” and two-component polyurea that cures in seconds. The thickness and lifespan vary even more.

Aerosol

Rubber sealant spray

Flex Seal Spray, Gorilla Waterproof Patch & Seal and similar. Made for cracks, seams and small holes. About 12 sq ft per 14 oz can.

Peel-off

Synthetic rubber dip

Plasti Dip and similar. Dip, brush or spray on tool handles, trim and wheels. Removable when applied properly.

Automotive

Rubberized undercoating

Auto-parts aerosols for frames and wheel wells. A soft, matte film of about 5–15 mils that gets reapplied every few years.

Pails

“Liquid rubber” sealers

Brush, roll or heavy airless. The one we checked is 40–60% asphalt cement by its SDS. Sold for roofs, foundations, planters and ponds.

Pro-sprayed

Polyurea and polyurethane

Two components mixed at a heated spray gun. Gels in seconds and builds 60–125 mils. Spray-on bedliners are the familiar example.

In between

Roll-on liner kits

Textured one-gallon kits (Herculiner type) you roll on in two coats. Tougher than a can, far thinner than a sprayed liner.

TypeWhat’s in itApplied withFilm you getDry / cureWater limitsPublished life
Aerosol rubber sealant (Flex Seal Spray, Gorilla spray)Not disclosed; Flex Seal “cures by evaporation”Aerosol can, 8–12 in awayThickness not published; ≈12 sq ft per 14 oz canTouch-dry 2–3 h; cure 24–48 h (Flex Seal); 24 h (Gorilla)Rainwater pressure (Flex Seal); “not for continuous submersion” (Gorilla)“Years,” no number (Flex Seal)
Peel-off rubber dip (Plasti Dip)Synthetic rubber; thins and cleans up with naphtha, xylene or tolueneAerosol, dip, brush or spray gun≈6 sq ft at 5 mils per 11 oz can; 10–12 mils is “adequate”30 min between coats; 4 h before useNo immersion rating; limited petroleum resistanceNot published
Rubberized undercoatingRubberized coating for undercarriagesAerosol or low-pressure gun5–15 mils1–4 hSplash and road spray2–5 years, then reapply
“Liquid rubber” pails (Liquid Rubber Waterproof Sealant)Asphalt cement 40–60% plus polymers; water-basedBrush, roller or heavy airless (≈4,000 psi)≈64 mils dry at 15 sq ft/gal (our estimate)24–48 h at 77°F, 50% RHNot for walking surfaces; not certified for potable water5–10 years before recoat
Sprayed polyurea (ArmorLiner, HighLine, spray-in bedliners)Isocyanate + amine resin, mixed at the gunHeated plural-component rig, 140–160°F, 2,000–3,000 psi60–125 milsGel 6–10 s; tack-free under 30 s; ≈1 h to serviceImmersion service; potable only with a certified grade15–25 yr (roofs); 20–30 yr (general)
Sources: Flex Seal FAQ and reference guide, Gorilla product page, Plasti Dip FAQ, Liquid Rubber TDS/SDS/coverage sheet, and ArmorThane’s truck undercoating, polyurea, elastomeric and roof coating guides. The liquid rubber film is our math from its 15 sq ft/gal flat-roof rate and 60–63% solids by weight, so treat it as an estimate.

The word you’re looking for: elastomeric

If you’ve been searching for “a liquid spray that dries to a rubberized coating,” the technical term is an elastomeric coating. A coating qualifies when it stretches at least 100% before breaking in the ASTM D412 tension test. Polyurea and polyurethane systems commonly test at 300–600%. Our elastomeric coating guide covers the whole category, including acrylics and silicones.

“Liquid rubber” usually isn’t rubber

Brand names do a lot of work here. The bucket product literally named Liquid Rubber lists asphalt cement at 40–60% by weight on its safety data sheet, blended with polymers into a water-based emulsion. That’s a legitimate, very stretchy waterproofing material: its data sheet claims more than 950% elongation. It just isn’t rubber in the way most buyers imagine, and it behaves like an asphalt coating: black, soft, not meant to be walked on. Roof coatings sold as “rubber” are just as mixed, as our rubber roof coating guide shows label by label.

The honest verdict

Does spray on rubber really work?

Yes, for the job on the can: sealing cracks, seams and small holes that see rain and splash, not standing water, traffic or constant flexing. The makers say so themselves. Flex Seal’s FAQ says its spray withstands “normal hydrostatic water pressure such as rainwater.” Gorilla’s spray is “not for continuous submersion or below-waterline use” and not for gaps larger than 1/4 inch.

Good use of a can

Where aerosol rubber shines

  • A leaking gutter seam, downspout joint or drip edge
  • Flashing around a vent, skylight or antenna (as a patch, not a roof)
  • Trailer and camper seams, above the waterline
  • Cracked planter, birdbath or outdoor light housing
  • Tool grips, wire handles, wheels and trim (peel-off dip)
  • Touching up undercoating in a wheel well
Wrong tool

Where it disappoints

  • A whole roof field, especially with ponding water
  • Pond, pool or tank interiors that stay full
  • Boat hulls below the waterline
  • Truck beds, walkways, ramps and anything driven or walked on
  • Drinking water: Flex Seal says it isn’t approved for potable use, and Gorilla says its spray isn’t food safe
  • Big areas: at 12 sq ft a can, a 200 sq ft deck is 17 cans

The pattern behind most failures is thickness. Flex Seal’s directions say to keep adding coats “if light can pass through.” That’s a fair description of how thin an aerosol film is. It stretches over a hairline crack beautifully. Put a boot, a tire or a pound of pressure on it every day and it wears through.

What about the TV demos?A demonstration shows what a product can do once, under ideal conditions. The manufacturer’s own fine print is the better guide to what it’s rated for. Where a maker publishes a limit (submersion, potable water, walking surfaces, gap size), we’ve used it on this page. Where it publishes nothing (film thickness, lifespan), we say so.
Interactive tool 1 of 3

Which spray on rubber fits your job?

Tell the picker what you’re coating, how big it is and what it has to survive. It scores all six product types against the limits their makers publish, then tells you whether it’s a can-and-a-Saturday job or one for a sprayed polyurea applicator.

Product picker

Match the coating to the job

Scores are our heuristic built on published maker limits, not lab tests. Always check the data sheet of the exact product you buy.

A 10 ft gutter run ≈ 5 sq ft
It will face
Aerosol rubber sealantGood fit Score 9/10

For a small leak or seam at 10 sq ft, a DIY product is the sensible start.

Good fit 9/10

Aerosol rubber sealant

Flex Seal Spray or Gorilla Patch & Seal type

  • About 1 can at the maker’s ≈12 sq ft coverage.

About 12 sq ft per 14 oz can (Flex Seal). Cure 24–48 h. Rated for rainwater pressure; Gorilla says not for continuous submersion. Film thickness not published.

Workable 6/10

Liquid rubber in pails

Asphalt-emulsion sealer, brush, roll or heavy airless

The one we checked is 40–60% asphalt cement (SDS). 15 sq ft/gal on flat roofs. 5–10 years before recoat. Not meant for walking surfaces or potable water.

Wrong tool 3/10

Peel-off rubber dip

Plasti Dip type

  • The maker says some fading of fluorescent colors is inevitable.

About 6 sq ft at 5 mils per 11 oz can; 10–12 mils takes 4–5 spray coats. Removable when applied properly. Limited resistance to petroleum products.

Wrong tool 3/10

Rubberized undercoating

Auto-parts aerosol undercoat

  • Matches its typical 2–5 year recoat cycle.

About 5–15 mils. Typically reapplied every 2–5 years (ArmorThane undercoating guide).

Wrong tool 2/10

Roll-on liner kit

Herculiner type

Textured, always two coats. One gallon does a 6-ft truck bed. Touch-dry 2 h, cured 24 h. No published lifespan.

Wrong tool 0/10

Sprayed polyurea (professional)

ArmorLiner, SureGrip, AquaSafe, spray-on bedliners

  • Tiny job for a spray rig; setup costs the same for 5 sq ft as for 500.
  • Outdoors, use an aliphatic grade or topcoat; aromatic polyurea yellows in UV.
  • More durability than you asked for, and the highest up-front cost.

60–125 mils in one visit, tack-free in seconds, 15–30 years of service in our published guides. Needs a heated plural-component rig and a trained applicator.

How it scores: each job starts from a base fit for each product type, then loses points where a maker’s published limit is hit (Gorilla and Flex Seal on submersion, Liquid Rubber on walking surfaces and potable water, Plasti Dip on petroleum products, undercoating on its 2–5 year life) and where the area makes a product impractical (a 14 oz can covers about 12 sq ft). Polyurea loses points on tiny jobs because a spray rig costs the same to set up for 5 sq ft as for 500.

Interactive tool 2 of 3

How thick is spray on rubber? Mils, cans and credit cards

From a can, a few mils per coat. Plasti Dip says one 11 oz can covers about 6 sq ft at 5 mils, and that 10–12 mils (four to five spray coats) is adequate for most uses. Rubberized undercoat runs 5–15 mils. A credit card is about 30 mils. Professionally sprayed polyurea is built to 60–125 mils, two to four credit cards thick.

What a mil is, and the 1,604 rule

A mil is a thousandth of an inch (0.0254 mm). One U.S. gallon is 231 cubic inches, so spread 1 mil thick it covers 1,604 sq ft. That one number turns any label into a thickness:

  • Wet mils = 1,604 × gallons ÷ square feet covered.
  • Dry mils = wet mils × volume solids. A 100%-solids polyurea stays the same thickness; a water- or solvent-borne coating shrinks as it dries.
  • Gallons for a target = square feet × target dry mils ÷ (1,604 × solids).

Why aerosol cans never tell you mils

Much of what’s in an aerosol can is propellant and solvent that flash off. Plasti Dip is one of the few that publishes a thickness, and its own numbers show how little film is in a can: 6 sq ft at 5 mils is 30 “square-foot mils,” or about 0.019 gallons. That’s roughly 2.4 fluid ounces of dry rubber from an 11 oz can, by our math. Flex Seal publishes coverage (about 12 sq ft per 14 oz) but not thickness or solids, so its film can’t be calculated from public data.

Mils converter

Turn a label’s coverage into real thickness

Enter what the label says (amount and square feet covered). Solids by volume is on most technical data sheets; if it isn’t, leave 100% and read the result as wet film.

107 mils
Wet film, total
64 mils
Dry film (estimate)
1.63 mm
Dry, in millimeters
2.1
Credit cards thick
Your film (dry)
64 mils
Plasti Dip, “adequate”
10–12
Rubberized undercoat
5–15
Credit card
≈30
Polyurea, typical low
60
Polyurea, typical high
125

At 60% solids, a 30-mil dry film takes 3.12 gal per 100 sq ft (32 sq ft per gallon). This label’s rate already reaches your target in the stated coverage. Liquid Rubber publishes 60–63% solids by weight; we treat that as volume, so the dry figure is an estimate. Formula: wet mils = 1,604 × gallons ÷ sq ft; dry = wet × solids. A credit card is about 30 mils (0.76 mm).

FilmThicknessWhere the number comes from
One 11 oz Plasti Dip can over 6 sq ft5 milsPlasti Dip FAQ
Rubberized aerosol undercoating5–15 milsArmorThane truck undercoating guide
Plasti Dip, “adequate in most uses”10–12 mils (4–5 spray coats)Plasti Dip FAQ
Roll-on liner, two coats at ≈60 sq ft/gal≈27 mils wet; solids not publishedOur math from Herculiner’s quart coverage
Credit card≈30 mils (0.76 mm)ISO/IEC 7810
Liquid rubber pail, walls (30 sq ft/gal)≈53 wet / ≈32 dry milsOur math from the maker’s coverage sheet
Liquid rubber pail, flat roofs (15 sq ft/gal)≈107 wet / ≈64 dry milsOur math from the maker’s coverage sheet
Sprayed polyurea, bridging cracks up to 1/8 in60+ milsArmorThane polyurea guide
Sprayed polyurea, typical build60–125 milsArmorThane elastomeric and roof coating guides
The liquid rubber dry figures assume its 60–63% solids by weight are close to solids by volume. That’s our assumption, not the maker’s number.
Service life

How long does spray on rubber coating last?

Anywhere from a season to a few decades, and the thin products are the ones without a published number. Flex Seal says “many people have found Flex Seal will last for years.” Rubberized undercoating is typically reapplied every 2–5 years. One asphalt-based liquid rubber lists 5–10 years before recoating. Sprayed polyurea runs 15–25 years on roofs and 20–30 years in general service in our published guides.

CoatingPublished lifeWho says soWhat shortens it
Aerosol rubber sealantNo number; “for years”Flex Seal FAQTraffic, standing water, thin film, oily or dusty surface
Peel-off rubber dipNot published–Fuel and oil (limited petroleum resistance), abrasion, fading of bright colors
Rubberized undercoating2–5 years, then reapplyArmorThane undercoating guideStone chips, road salt, thin film
Acrylic elastomeric coatings5–10 years before recoatArmorThane elastomeric guidePonding water, thin build
Asphalt-based liquid rubber5–10 years before recoatLiquid Rubber product pageFoot traffic, ponding, poor prep
Sprayed polyurea roof coating15–25 yearsArmorThane roof coating guideUV on aromatic grades without a topcoat, thin spots
Polyurea / polyurethane elastomeric systems20–30 yearsArmorThane elastomeric guideAggressive chemical immersion, inadequate thickness, poor prep
Sprayed polyurea bedlinerLife of the vehicleArmorThane spray-on bedliners pagePoor prep, peeling edges
Maker and publisher estimates, not independent studies. The ArmorThane figures are ours; we’ve listed them so you can weigh them accordingly.

What kills a rubber coating

  • Too thin. A few mils over a moving crack or a walked-on surface wears through first. Thickness is the single biggest difference between a can and a sprayed membrane.
  • Standing water. Rain runs off; ponds and puddles sit. Liquid Rubber’s roof guidance calls for low and ponding areas to be fixed before coating.
  • Sunlight on the wrong chemistry. Aromatic polyurea, including our HighLine 510, isn’t UV-stable on its own and gets an aliphatic topcoat outdoors. Plasti Dip says some fading of its fluorescent colors is inevitable.
  • Petroleum. Plasti Dip lists “limited resistance to petroleum-based products,” so it’s a poor choice near fuel or oil.
  • Bad prep. Every maker we checked wants a clean, dry, sound surface. Coatings stuck to dirt, oil or flaking paint come off with it.

Can you recoat it?

Mostly yes, with the same product. Plasti Dip says you can apply as many coats as you like, and Herculiner says it adheres to itself. Liquid Rubber warns against combining its asphalt sealant with its silicone coating. Polyurea is spot-repairable: abrade the damaged area, clean it, reprime and respray with the matching system.

Interactive tool 3 of 3

Spray on rubber cost: cans, gallons or a pro

A 14 oz can of Flex Seal is $14.99 and covers about 12 sq ft, roughly $1.25 per square foot per application. A peel-off dip at 10 mils runs about $3.50 per square foot in 11 oz cans. An asphalt liquid rubber on a flat surface lands around $2.90–$4.70 per square foot depending on pail or gallon. A pro polyurea roof runs $3–$6 per square foot installed, at 60–125 mils.

Cost, cans and dry-time planner

What each option takes for your area

Prices observed in September 2026 on maker and retailer pages; pro polyurea from ArmorThane’s published installed ranges. Material only for the DIY rows: add tape, primer, rollers and your time.

$219.95
Cheapest suitable DIY: Liquid rubber pail
$180–$360
Pro polyurea, installed
≈64 mils
Thickest DIY film here
60–125 mils
Sprayed polyurea film
OptionYou’ll needCost$/sq ftFilmReady inPublished life$/sq ft per year
Aerosol rubber sealant (14 oz)
A patch product, not a roof coating.		5 cans$74.95$1.25Not published24–48 hNot published—
Peel-off rubber dip (11 oz)
Thin cosmetic film, not for this job.		20 cans, 4 coats$209.40$3.4910 mils≈5.5 hNot published—
Liquid rubber pail (asphalt-based)1 × 5 gal (4.0 gal)$219.95$3.67≈64 mils (est.)24–48 h cure5–10 yr$0.37–$0.73
Roll-on liner kit
Not sold as a roof coating.		1 kit$109.99$1.83≈27 mils wet≈26–28 h (2 coats)Not published—
Sprayed polyurea (installed)2.2–4.7 gal at 60–125 mils$180–$360$3.00–$6.0060–125 mils≈1 h to service15–25 yr$0.12–$0.40

Aerosol count uses the maker’s ≈12 sq ft per can; Flex Seal says to add coats until no light passes through, so budget extra cans for porous or cracked surfaces. Dip count uses Plasti Dip’s 6 sq ft at 5 mils per 11 oz can. Liquid rubber uses 15 sq ft per gallon (flat/low-slope rate) and buys the cheaper mix of 5-gal pails and gallons; primer not included. Roll-on kit assumes ≈60 sq ft per gallon in two coats. Pro range: ArmorThane roof coating guide, $3–$6 per sq ft installed. Estimates only. Get a written polyurea quote.

Reading the planner

Cost per square foot is only half the story. The aerosol row is cheapest for a small patch, but it’s also the thinnest film and the only one without a published thickness. The liquid rubber row buys real thickness for a roof or wall, but not a surface you walk on. The polyurea row costs the most up front and is the only one here with a published life measured in decades, which is why the planner also shows cost per square foot per year where a life is published.

ProductPrice observedCoverage stated
Flex Seal Spray, 14 oz / 17 oz MAX$14.99 / $16.99≈12 / ≈15 sq ft
Flex Seal Liquid (brush-on), gallon$109.99Not published
Plasti Dip aerosol, 11 oz$62.79 per 6-can case (≈$10.47 each)≈6 sq ft at 5 mils
Liquid Rubber Waterproof Sealant$69.95 / gal; $219.95 / 5 gal15 sq ft/gal flat; 30 sq ft/gal vertical
Herculiner roll-on kit / quart$109.99 / $39.996-ft truck bed, two coats / 15 sq ft, two coats
Pro polyurea roof coating$3.00–$6.00 per sq ft installed60–125 mils
Pro polyurea garage floor$3–$7+ per sq ft installed–
Pro spray-on bedliner$400–$900 per truckAbout 5 gallons for a full-size bed
Prices from each maker’s site or the retailer listed in the sources; installed ranges from ArmorThane’s roof coating guide, polyurea guide and spray-on bedliners page. Prices change; check before you buy. For a deeper bedliner price breakdown, see spray-in bedliner cost.
Surface by surface

Spray on rubber coating by surface: metal, wood, concrete and more

Aerosol rubber sealants list almost everything as a compatible surface: wood, metal, tile, concrete, masonry, fabric, glass, plastic and more. Listing a surface isn’t the same as lasting on it. What decides the result is prep, the exposure and the thickness. Here’s how that plays out on the surfaces people ask about most.

Metal

Rust is the enemy of adhesion. Flex Seal’s how-to says to sand rust off before spraying, and every maker wants the surface free of grease and oil. For a trailer seam or a rusty gutter, that’s enough. For steel that will be immersed or abraded, professionals abrasive-blast to near-white metal (SSPC-SP 10) before polyurea. Some polyureas, such as our HighLine 510, go on prepared carbon steel without a primer.

Wood

Wood moves with moisture, which suits a flexible coating, but it has to be dry when you coat it. Liquid Rubber calls for its multipurpose primer on wood, PVC and fiberglass. Test a small patch first, especially over stain or old sealer.

Concrete and masonry

Concrete is porous, dusty and often damp. Cans and pails want it clean and dry; Liquid Rubber adds a primer and an etch for concrete. For floors, foundations and water-holding structures, sprayed polyurea goes over concrete that’s been diamond-ground or shot-blasted to a CSP 3–5 profile. Our polyurea waterproofing page covers foundations, decks and tanks.

Plastic, vinyl and rubber

This is where the cans are least predictable. Flex Seal’s reference guide says it “may not be compatible with some plastics, vinyl, rubbers,” and Gorilla says the same about some plastics and rubbers. Low-energy plastics are hard for any coating to grip. Spray a patch, let it cure fully, then try to peel it off with a fingernail before you commit.

Fabric and rug backing

Aerosol sealants list fabric among their surfaces, which makes them handy for waterproofing a seam in a tarp or canopy. We haven’t found published wear data for any of these cans on rug backing or anything that gets walked on and vacuumed, so treat that use as an experiment.

Roofs

An aerosol is a patch for a flashing, a vent boot or a seam, not a roof. Coating the whole field takes gallons, a primer that matches the membrane and enough thickness to handle sun and ponding. Many “rubber” roof coatings are actually acrylic, silicone, asphalt or butyl; our rubber roof coating guide decodes them and covers EPDM specifically. A sprayed polyurea roof coating runs $3–$6 per square foot installed and builds 60–125 mils in one visit.

Cars, trucks and undercarriages

Peel-off dip is for cosmetic jobs you might want to undo: wheels, emblems, grilles, trim. Rubberized undercoating in a can gives an undercarriage about 5–15 mils of basic protection and needs redoing every few years. Sprayed polyurea undercoating goes on at 60–125+ mils. Our truck undercoating guide compares rubberized, oil-based, polyurethane and polyurea undercoats side by side.

Truck beds

A truck bed is the clearest case for professional spray. It takes impact, abrasion and standing water every day. A roll-on kit like Herculiner does a 6-ft bed with one gallon in two coats, about 27 wet mils by our math. Our applicators typically put about 5 gallons into a full-size bed. A professional spray-on bedliner typically costs $400–$900 and cures into what we describe as “a tough, rubberized layer that is seamless and permanent.”

Pickup truck bed coated wall to wall with a textured black spray-on polyurea bedliner
A sprayed polyurea bedliner: the same “spray-on rubber” idea, built to a thickness no can can match.

Ponds, fountains and planters

A pond holds water against the coating around the clock, so it needs a product rated for that service and a data sheet that says so. Flex Seal and Gorilla sprays aren’t rated for continuous submersion. Some bucket liquid rubbers are sold for ponds and planters; if you have fish, ask the maker for a written fish-safe statement for that exact product. Our koi pond liner guide compares EPDM, PVC, liquid coatings and sprayed polyurea for ponds.

Drinking-water tanks and cisterns

Skip the cans and the pails. Flex Seal says it isn’t approved for potable water, and Liquid Rubber’s data sheet says its sealant is “not food grade or certified for potable water.” A drinking-water lining needs a coating certified for potable contact. Ours is AquaSafe, a pure polyurea tested by an ANSI-accredited lab and rated for direct contact with drinking water.

Do it right

How to apply spray on rubber so it actually sticks

Clean and dry the surface, check the temperature, test a patch, then build thin coats until you reach the film the product needs, and let it cure before water or use. The steps below apply to cans and pails. Sprayed polyurea follows the same logic with much stricter prep and a heated rig.

  1. Pick the product for the exposure

    Submersion, traffic, fuel and drinking water each rule out some products before you start. The picker sorts that out in a minute.

  2. Clean, dry and sound

    Flex Seal wants the surface “clean, dry, and free of grease, oil, and dirt.” Liquid Rubber’s list adds coal tar, mastics, flaking paint and silicone. Sand off rust, scrape loose coatings and let damp wood or concrete dry out.

  3. Check the weather, not just the can

    Flex Seal wants the can above 60°F and applies from 0°F to 100°F. Plasti Dip’s ideal is 70°F, low humidity and still air, out of direct sun. Liquid Rubber wants 50–86°F including overnight, under 80% humidity, with no rain, fog or dew forecast for 24 hours. Polyurea applicators keep the surface at least 5°F above the dew point.

  4. Mask and test a patch

    Overspray travels. Mask what you don’t want coated, then spray a small test area and let it cure. If it peels easily, fix the prep or change products.

  5. Spray thin coats, crosshatched

    Hold aerosols 8–12 inches away (Flex Seal) or 6–10 inches (Plasti Dip), overlap each pass and don’t try to build it all at once; heavy coats sag and drip. With pails, alternate direction each coat and finish in the direction of the slope.

  6. Build to thickness, then check it

    Plasti Dip needs four to five spray coats for 10–12 mils, 30 minutes apart. Flex Seal says to add coats until light no longer passes through. Professionals measure wet film during application and dry film afterward.

  7. Let it cure before water or use

    Plasti Dip: 4 hours before use. Gorilla spray: 24 hours. Flex Seal Spray and Liquid Rubber: 24–48 hours. Flex Seal Liquid: 24–48 hours between coats and 48 hours to cure. Sprayed polyurea: about an hour to return to service.

Ventilation and fireFlex Seal says to use its spray only in a well-ventilated area and never near heat, sparks or pilot lights. Solvent-borne dips thin and clean up with naphtha, xylene or toluene, which are flammable. Two-component polyurea is a different hazard: OSHA lists isocyanate exposure effects including skin and airway irritation, chest tightness and occupational asthma, which is why applicators spray in full suits with respirators.

What spray on rubber won’t stick to

  • Silicone and coal tar. Liquid Rubber says not to apply its sealant over either.
  • Some plastics, vinyl and rubbers. Both Flex Seal and Gorilla flag them. Test first.
  • Oil, grease, dust and chalky old paint. The coating bonds to the contamination, not the surface.
  • Gaps wider than about 1/4 inch. Gorilla sets that limit for its spray. Fill or bridge bigger gaps first.

Can you spray liquid rubber with a regular sprayer?

Aerosols, yes; that’s the point. Bulk liquid rubber is thick. One maker’s data sheet calls for an elastomeric-rated airless rig at about 4,000 psi and 4 gallons per minute with a 0.525–0.535 tip and a 13 HP motor, which is a contractor machine, not a paint-store rental. Polyurea goes further: a heated plural-component proportioner at 140–160°F and 2,000–3,000 psi, mixing two components at the gun. Standard airless sprayers can’t do that.

Call a pro, or don’t

When to hire a polyurea applicator (and when not to)

Hire when the coating has to be the membrane: when it holds standing water, takes foot or vehicle traffic or impact, covers more than a few dozen square feet, or has to last a decade or more. Don’t hire for a gutter seam, a vent boot, tool grips or wheels you might peel later. A can does those jobs, and a spray rig costs the same to set up for 5 sq ft as for 500.

Hire

Jobs for sprayed polyurea

  • Truck beds, trailer floors, dump bodies and equipment
  • Ponds, fountains, water features and tanks
  • Drinking-water tanks (with a certified grade)
  • Roofs and decks you want to stop recoating
  • Walkways, ramps and anything that needs grip (soft, high-friction grades)
  • Secondary containment and anything near fuel or chemicals
DIY is fine

Jobs for a can or a pail

  • A leak you can see, above the waterline
  • Seams, flashings and penetrations as a stopgap
  • Anything you want to be able to peel off
  • A small area where a contractor minimum dwarfs the job
  • A wall or foundation you’re sealing with a bucket product rated for it
  • Short-term fixes while you plan the real repair

Can you buy polyurea and spray it yourself?

Contractors can buy our polyurea without a certification. Spraying it is another matter. It gels in 6–10 seconds, so it isn’t a brush or roller product; it needs a heated plural-component rig, correct ratio and temperature, and surface prep done to a standard. Get any of that wrong and you get adhesion failure, blisters or soft spots. That’s the argument in our post on why DIY polyurea is usually a mistake, and it’s why we sell equipment and training together.

Eight questions to ask a polyurea applicator

  1. Which product exactly, and can I see its technical data sheet?
  2. Is it aromatic or aliphatic? If aromatic and outdoors, what’s the UV topcoat?
  3. What thickness, in mils, and will that be in writing?
  4. How will you prepare the surface (grinding or shot-blasting for concrete, abrasive blast for steel)?
  5. Which primer, if any, and why?
  6. How will you check thickness during and after spraying?
  7. For tanks and containment: will you holiday-test for pinholes?
  8. What does the warranty cover, and who backs it?
Find a certified polyurea applicator
What we make

Sprayed polyurea: the professional spray-on rubber

Polyurea is an elastomer formed when an isocyanate reacts with an amine resin. The two sides are pumped separately, heated, and mixed in the gun, so the reaction starts the instant the spray leaves the tip. It gels in seconds, builds 60–125 mils in one visit and bonds to prepared steel, concrete, wood, fiberglass and geotextile.

As “rubber,” it spans a wide range. Our catalog runs from soft, grippy SureGrip at about Shore 50–60A, through ArmorLiner at 75–85A, to HardCoat at 60–70D for coating foam. Polyurea and polyurethane elastomers in our published data test at 2,500–4,500 psi tensile and 300–600% elongation (ASTM D412). See the full polyurea product line or the chemistry in our polyurea guide.

Get a polyurea quote →Polyurea products
Applicator in a protective suit and full-face respirator spraying polyurea bedliner into a masked pickup bed with a plural-component gun
Two components, mixed at the gun, sprayed by a trained applicator.
75–85A

ArmorLiner

One of our most widely used systems: bedliners, roofing, containment and general protection, with low-temperature flexibility.

50–60A

SureGrip

Our softest, highest-elongation polyurea with the highest coefficient of friction. Sprays down to −20°F.

Potable

AquaSafe

Pure polyurea rated for direct contact with drinking water. Elongation up to 450%.

Where polyurea is the wrong answer

We’d rather you spend $15 than $500 if $15 does the job. Polyurea is overkill for a one-off leak, a gutter seam or anything you’ll want to peel off later. It’s permanent. Aromatic grades yellow in sunlight without an aliphatic topcoat or an aliphatic grade like ArmorFlex UV, and a cheap polyurea job with poor prep will fail as surely as a can. It also costs more up front than anything else on this page. Its advantage is thickness and service life, so it pays off where those matter.

For contractors

People search “spray-on rubber.” You could spray it.

Every search on this page is a customer who wants a tougher coating than a can. A polyurea rig lets you line truck beds, trailers, ponds, roofs and floors from one setup. We make the material, build the equipment and train your crew. Startup packages begin at $25,000, with no franchise fee and no royalties.

Become an applicatorSee equipment costs

Questions? Call (417) 831-5090 in the U.S. or 780-444-6200 in Canada.

Straight answers

Spray on rubber coating FAQ

Is there a spray-on rubber coating?

Several. Aerosol rubber sealants (Flex Seal type), peel-off synthetic rubber dips (Plasti Dip), rubberized undercoating, brush-or-spray "liquid rubber" sold in pails, and plural-component polyurea sprayed by a professional all dry to a rubbery film. They differ in chemistry, thickness and lifespan far more than the labels suggest.

Does spray-on rubber really work?

For small leaks and seams above the waterline, yes. Makers are clear about the limits: Flex Seal says its spray withstands normal hydrostatic pressure such as rainwater, and Gorilla says its spray is not for continuous submersion or below-waterline use. For ponds, truck beds, walkways and whole roofs you need a thicker membrane.

How long does spray-on rubber last?

It depends on the product. Aerosol makers don't publish a number, rubberized undercoating is typically reapplied every 2–5 years, one asphalt-based liquid rubber lists 5–10 years before recoating, and professionally sprayed polyurea runs 15–25 years on roofs and 20–30 years in general service in our published guides.

How long does spray rubber take to dry?

Flex Seal Spray is dry to the touch in 2–3 hours and fully cured in 24–48 hours. Plasti Dip needs 30 minutes between coats and 4 hours before use. Bulk liquid rubber cures in 24–48 hours in mild weather, and sprayed polyurea gels in seconds and returns to service in about an hour.

How thick is spray-on rubber?

Thin, unless it's sprayed by a pro. One 11 oz can of Plasti Dip covers about 6 sq ft at 5 mils, rubberized undercoat runs 5–15 mils, and a credit card is about 30 mils. Sprayed polyurea is built to 60–125 mils. Use the thickness converter to turn any label's coverage into mils.

Can liquid rubber be sprayed?

Yes, but not with a hardware-store sprayer. One bulk liquid rubber's data sheet calls for an airless rig rated about 4,000 psi and 4 gallons a minute with a 0.525–0.535 tip. Sprayed polyurea needs a heated plural-component proportioner running 140–160°F at 2,000–3,000 psi.

What does Flex Seal not stick to?

Flex Seal's own guide warns it may not be compatible with some plastics, vinyl and rubbers, and it needs a surface that is clean, dry and free of grease, oil and dirt. Silicone, coal tar and flaking paint are common adhesion problems for liquid rubbers generally. Always do a small test patch.

Can you spray Flex Seal on rubber?

Flex Seal lists rubber among its surfaces, but its reference guide also says it may not be compatible with some rubbers. Clean the surface, spray a test patch, let it cure and try to peel it before you coat the whole part.

Is spray-on rubber waterproof?

The film sheds water, but waterproof and submersible aren't the same thing. The aerosol makers rate their sprays for rain and splash, not continuous submersion. For ponds, tanks and anything that holds water, use a membrane built for immersion, such as sprayed polyurea waterproofing.

Is liquid rubber safe for fish or drinking water?

Not for drinking water: Flex Seal says it isn't approved for potable water, and one liquid rubber's data sheet says it is not food grade or certified for potable water. For fish, ask the maker for a written fish-safe statement for that exact product. Drinking-water tanks need a coating certified for potable water contact, such as our AquaSafe polyurea.

Is a spray-on bedliner the same as spray-on rubber?

It's the professional version of the idea. A spray-on bedliner is polyurea or polyurethane sprayed from a heated rig, and it cures into a tough, rubbery, seamless layer that's far thicker than anything from a can. A pro bedliner typically runs $400–$900; see our spray-on bedliner page.

Can I buy polyurea and spray it myself?

Contractors can buy our polyurea without certification, but it takes a heated plural-component rig and training to spray. It gels in seconds, so it isn't a brush or roller product. For a one-time project, hire an ArmorThane-certified applicator; if you want to do it for a living, look at a startup package.

AT
ArmorThane Technical Team · Springfield, Missouri
Written from manufacturer data sheets, safety data sheets and our own product data, by a team that has made and sprayed polyurea for 35+ years. Last updated September 26, 2026.

Methodology and sources

Product specs, limits and prices come from each maker’s own product page, FAQ, technical data sheet or safety data sheet, observed in September 2026; Plasti Dip case pricing is from the retailer listed. Film thicknesses marked as ours use the 1,604 sq ft per gallon-mil rule; the liquid rubber dry film assumes weight solids approximate volume solids. ArmorThane figures come from our published product pages and guides. Picker scores are a heuristic, not test results. Where a maker publishes no number (aerosol film thickness, lifespan), we don’t invent one.

  1. Flex Seal, Flex Seal Spray product page (prices, directions; observed Sep. 2026): flexsealproducts.com/products/flex-seal
  2. Flex Seal, FAQs (coverage, cure, temperature, water limits): flexsealproducts.com/pages/faqs
  3. Flex Seal, aerosol reference guide (PDF): cdn.shopify.com/s/files/1/0282/4414/8333/files/FS-_4754_FS_AeroNew_Ref
  4. Flex Seal, how to use Flex Seal Spray: flexsealproducts.com/blogs/how-to/how-to-use-flex-seal-spray
  5. Flex Seal, Flex Seal Liquid product page: flexsealproducts.com/products/flex-seal-liquid
  6. Gorilla, Waterproof Patch & Seal Spray: gorillatough.com/product/gorilla-waterproof-patch-and-seal-spray/
  7. Plasti Dip, FAQs (coverage, thickness, coats, chemical resistance): plastidip.com/faqs/
  8. A Warehouse Full, rubberized coating listings (Plasti Dip prices; observed Sep. 2026): awarehousefull.com/rubberized-coating/
  9. Liquid Rubber, Waterproof Sealant product page (prices, limits, lifespan): shopliquidrubber.com/products/waterproof-sealant
  10. Liquid Rubber, Waterproof Sealant technical data sheet (PDF): shopliquidrubber.com/cdn/shop/files/Liquid_Rubber_Waterproof_Sealant_T
  11. Liquid Rubber, Waterproof Sealant safety data sheet (PDF): shopliquidrubber.com/cdn/shop/files/LRC_Waterproof_Sealant_SDS.CANUSA.
  12. Liquid Rubber, Waterproof Sealant coverage rates (PDF): shopliquidrubber.com/cdn/shop/files/LR-Waterproof_Sealant-Coverage_Rat
  13. Herculiner, roll-on bed liner kit: herculiner.com/bed-liner-kit
  14. Herculiner, bed liner quart: herculiner.com/bed-liner-quart
  15. Protek Paint, liquid rubber spray and dip coatings: protekpaint.com/liquid-rubber-paint-spray-coating/
  16. OSHA, Isocyanates: osha.gov/isocyanates
  17. ASTM D412, tension testing of rubber and thermoplastic elastomers: astm.org/d0412-16r21.html
  18. ISO/IEC 7810 card dimensions (card thickness): en.wikipedia.org/wiki/ISO/IEC_7810
  19. ArmorThane, polyurea products and hardness table: armorthane.com/products/polyurea/
  20. ArmorThane, polyurea guide: armorthane.com/polyurea-guide/
  21. ArmorThane, elastomeric coating guide: armorthane.com/knowledge-center/elastomeric-coating-guide/
  22. ArmorThane, roof coating guide: armorthane.com/knowledge-center/roof-coating-guide/
  23. ArmorThane, truck undercoating guide: armorthane.com/knowledge-center/truck-undercoating-guide/
  24. ArmorThane, spray-on bedliners: armorthane.com/protective-coatings/spray-on-bedliners/
  25. ArmorThane, AquaSafe pure polyurea: armorthane.com/products/armorline-products/high-pressure/aquasafe-pure

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Need more than a can?

ArmorThane-certified applicators spray polyurea at the thickness your job needs and put the product, prep and mils in writing. Contractors: we make the material, build the rigs and train your crew, with no franchise fee and no royalties.

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