How to Clean an RV Awning: Vinyl, Acrylic, Mold and Sap
Scrub both faces with mild soap, roll the awning up wet 10 minutes, unroll and rinse. Diluted bleach on vinyl only, never acrylic, never a pressure washer.
Clean an RV awning with a bucket of warm water and a few ounces of mild dish soap, a soft brush, and the roll-in-wet method: scrub both faces, roll the awning up damp for 10 minutes, then unroll and rinse. Diluted bleach is for vinyl only. Acrylic gets soap, and no awning gets a pressure washer.
Is your awning vinyl or acrylic, and what will each one tolerate?
Stand under the awning at midday and look up. If you see pinpoints of daylight through a visible weave, it is acrylic. If the fabric blocks light completely and feels slick, like a pool liner, it is vinyl. That one look decides whether bleach is a tool or a mistake.
Vinyl awning fabric is a woven polyester scrim with a PVC coating bonded to both sides. It is waterproof because it is sealed, not because it is treated, so the surface is what you are cleaning and the surface takes chemistry well. Mildew does not eat vinyl. It eats the dirt, pollen and plasticizer sitting on top of the vinyl, which is why the black dots wipe off a well-kept awning and stay on a neglected one. Almost every factory patio awning from Dometic, Carefree of Colorado and Lippert Solera leaves the plant as vinyl.
Acrylic is a different animal: solution-dyed acrylic yarn woven into a breathable cloth, then given a fluoropolymer water-repellent finish at the factory. The colour is locked into the fibre, so acrylic holds its shade for 10 years where vinyl fades in 5. The finish, however, is a thin sacrificial coating that sits on the yarn, and chlorine bleach strips it. The fabric survives the bleach and the water repellency does not, which is how people end up with an awning that soaks through and drips on their heads two weeks after they cleaned it.
| Vinyl (coated PVC) | Acrylic (solution-dyed woven) | |
|---|---|---|
| Diluted bleach | Yes, 1:40 in water, 10 minutes, rinse hard | No, it strips the water-repellent finish |
| Mild dish soap | Yes | Yes, this is the standard cleaner |
| Degreasers and citrus cleaners | No, they attack the plasticizer and leave a tacky patch | No, they carry the finish away with the dirt |
| Stiff brush | No, medium-soft bristle only | No, soft bristle, brush with the weave |
| Pressure washer | No, it delaminates the coating from the scrim | No, it drives water and dirt through the weave |
| Mildew lives | On the surface film, so it washes off | In the weave, so it needs dwell time |
| Needs re-treating after cleaning | UV protectant | Fabric waterproofing spray |
If you are not sure which fabric you have and the awning is old enough that it might be a previous owner’s replacement sheet, replacing RV awning fabric covers how the two materials are ordered and marked. When in doubt, treat it as acrylic: soap will never wreck a vinyl awning, but bleach will wreck an acrylic one.
What is the best cleaner for an RV awning?
Warm water with 1/4 cup of mild liquid dish soap per 5 gallons cleans 90% of what lands on an awning, and it is what both Dometic and Carefree of Colorado put in their own care sheets. Dish soap works because it is a plain surfactant with no solvent and no degreaser in it. The homemade version people ask about is the branded version, minus the label.
For vinyl carrying actual mildew, add 1 cup of 5–6% household bleach to that same 5 gallons. That is roughly a 1:40 dilution, strong enough to kill spores and weak enough that a 10-minute contact time will not attack the stitching. Do not go stronger. The straight-bleach-in-a-spray-bottle approach that gets passed around campgrounds bleaches the polyester thread at the seams first, and a seam failure shows up as a hem letting go in a crosswind two seasons later.
A homemade mix worth keeping is 1 part white vinegar to 3 parts warm water for hard-water spotting and light grey film. It shifts mineral deposits that soap slides over, and it is safe on both fabrics. What does not belong anywhere near an awning: engine degreaser, wheel cleaner, oven cleaner, bug and tar remover, and any citrus product listing d-limonene. All of them lift dirt beautifully and all of them dissolve either the PVC coating or the acrylic’s finish while they do it.
How to clean an RV awning: the roll-in-wet method
The trick that separates a 45-minute job from an afternoon on a ladder is letting the awning clean its own underside. You wet both faces, then roll the awning up damp so the cleaner is pressed between the wraps and soaks the underside while you do something else.
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Extend the awning fully and drop one end
Run it all the way out, then lower the arms so the fabric sits at chest height and pitched to one side. Expected: the sheet is taut, you can reach the middle with a pole brush, and rinse water runs off one corner instead of pooling.
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Dry-brush the loose debris off the top
A soft broom clears pine needles, leaf mat and the grit sitting in the roller channel. Expected: nothing left on the fabric that would turn to mud the moment you add water.
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Wet both faces with a garden hose
Plain water, no nozzle pressure, top face then underside. Expected: the fabric is evenly dark with no dry patches, which is what stops the cleaner drying into a tide line.
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Mix the cleaner in a bucket or pump sprayer
5 gallons of warm water plus 1/4 cup dish soap. On vinyl with mildew, add 1 cup of household bleach. Expected: a light suds, not a foam bath. Excess soap is just more rinsing.
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Wash the underside first, in 4 ft sections
Soft-bristle brush on a pole, light pressure, overlapping strokes. The underside is dirtier than the top because that is where mildew grows. Expected: the grey lifts and the runoff turns brown.
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Wash the top face the same way
Work from the roller tube outward to the front rail so dirty water always runs off the edge you have not cleaned yet. Expected: black streaks near the roller fade, sap spots stay for now.
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Roll the awning up wet and walk away for 10 minutes
Five minutes if the fabric is in full sun. The wraps hold cleaner against both faces and the dwell time does the work a brush cannot. Expected: cleaner still wet when you unroll, never dried in place.
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Unroll and hit what survived
Mildew dots, sap and droppings get spot treatment now, on fabric that is already soft and wet. Expected: black spotting gone or clearly faded to grey. A second soak beats a harder brush.
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Rinse until the water runs clear and the fabric stops feeling slick
Rinse the underside twice. Soap residue is a mildew food source, so a half-rinsed awning grows spots faster than a dirty one. Expected: no foam at the low corner, no slippery feel to the fabric.
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Leave it out until both faces are bone dry
20–45 minutes in sun and moving air. Check the last wrap of fabric nearest the roller tube, which is the part that stays damp. Expected: dry to the back of your hand everywhere, then roll it up.
Total working time is about 25 minutes on a 16 ft awning. The rest is soak and dry. Doing the same job by ladder and rag, one square foot at a time, is what turns awning cleaning into the chore people put off for three years.
How do you clean mildew off the underside of an RV awning?
Mildew on the underside is killed by contact time, not by scrubbing. Wet the fabric, apply the cleaner, roll the awning up for 10 minutes so the solution stays in place, then unroll and rinse. On vinyl that means the 1:40 bleach mix. On acrylic it means soap, a second soak, and patience.
The black dots are the visible part of a colony that started when someone rolled a damp awning up after a rainy weekend and drove home. Rolled fabric in a dark tube at 80 °F is a laboratory incubator, and 48 hours is enough to seed it. The underside gets hit first because it never sees direct sun and never fully dries.
Two soaks beat one long one. A ten-minute dwell, a rinse, then a second ten-minute dwell removes spotting that a single 30-minute soak leaves behind, because the first pass strips the surface film that was shielding the colony. If the dots have faded to grey shadows and stopped moving after the second pass, they are no longer alive, and what you are looking at is staining in the coating rather than growth on it.
Tree sap, bird droppings and black streaks
Sap comes off with 70% isopropyl alcohol on a cloth, dabbed rather than rubbed, and it comes off far more easily while the fabric is still wet from the wash. Test on a corner near the roller tube first: alcohol is safe on vinyl and on acrylic, but a heavily faded 12-year-old sheet can lift colour anywhere. Work the alcohol in circles from the outside of the spot inward so you do not spread the softened sap, then wash that patch again with soap and rinse.
Bird droppings are uric acid and they etch. Never scrape one dry, because the grit inside a dropping is essentially sandpaper and it takes the coating with it. Lay a soapy wet cloth over the spot for 10 minutes to soften it, then lift it off in one motion and rinse. A dropping left through a hot week leaves a permanent light patch on vinyl even after it is removed.
The black streaks running down the front and back edges of an awning are not awning dirt. They are the same oxidized runoff that streaks the sidewalls, arriving from the roof and the drip rail above, so an awning cleaned every spring will streak again by August unless the roof above it is clean too. Cleaning the RV roof is what stops the streaks at the source, and washing and detailing the rig covers the streak removers that are safe on gelcoat.
Do not skip the arms, the roller tube and the slide toppers
Awning arms fail from grit, not from age. The telescoping sections and the slide channels collect road dust that turns into grinding paste, and a stiff awning that needs two hands and a grunt is almost always dirty rather than broken. Wash the arms and the rafter joints with the same soapy water, rinse them, dry them, then lubricate the sliding surfaces with dry silicone spray. Not oil, not white lithium grease: oil holds dust and it stains fabric black at every point the arm touches the sheet.
The roller tube itself needs a wipe along its full length while the awning is out, because the last 12 inches of fabric that wrap it sit against whatever is on that tube for the entire storage season. Clear the awning rail on the side of the RV too. A rail packed with pine needles holds water against the sealant bead above it.
Slide toppers are the awnings nobody cleans, since they cannot be lowered and they only exist while the slide is out. Extend the slide fully, then work from a ladder or with a pole brush from the roof edge, using soap only. Toppers pool water and hold leaf litter in the sag, so they grow mildew faster than the patio awning and are the first thing to develop a green stripe down the middle. While you are up there, check the topper tension and the slide seals, since slide-out maintenance and topper wear go together.
Why drying matters more than the cleaning itself
Every mildew problem on an RV awning starts with a damp roll-up. The fabric must be dry on both faces before it goes back on the tube, and the underside dries last because it is shaded by the sheet above it.
Give it 20 minutes of sun and moving air after the final rinse, then run the back of your hand along the underside near the roller tube. That final wrap is the section that stays cool and damp, and it is where the black speckling always starts. If the sky opens on you and you have to travel with a wet awning, roll it, drive, and unroll it within 24 hours at the next stop, even for an hour. Two days is where spores establish.
Before the rig goes into storage, the awning gets a wash, a full dry and then a full day rolled up in a dry spell before the cover goes on. A long-term storage checklist that skips this step is where most spring awning surprises come from.
Do you need a UV protectant after cleaning?
Yes on both fabrics, and the product differs. Vinyl wants a water-based UV protectant of the aerospace-style 303 type, sprayed on clean dry fabric and wiped even, reapplied every 3–6 months. It blocks the UV-B that makes the PVC coating brittle and chalky, and it leaves a slick surface that sheds dirt so the next wash is faster.
Acrylic wants re-waterproofing instead. The factory fluoropolymer finish wears off with cleaning, sun and time, so a fabric water-repellent spray goes on once a year, or immediately after any deep clean where you used more than soap. Apply two light coats to dry fabric rather than one heavy one, overlapping by half, and let each coat flash off for 20 minutes. The test is a cup of water poured on the sheet the next day: beads that roll off mean the finish took, and a dark wet patch that spreads means it did not.
Never treat damp fabric with either product. You will seal moisture under the coating, and on acrylic that produces a blotchy finish that cannot be evened out without stripping it. Aftermarket cleaners, protectants and replacement sheets for both fabrics are collected in the RV awning buying guide.
How often should you clean an RV awning?
Deep clean twice a year for a rig used most weekends, three times if it lives under trees, and always once before storage. Between those, a plain hose rinse every month costs five minutes and removes the pollen and dust film that mildew feeds on.
The interval is set by where you park, not by how much you use the awning. Pine and oak drop sap and tannin that stain within a week. Coastal salt air leaves a film that holds moisture against the fabric. A rig parked in dry high desert can go a full year on rinses alone. Full-time in the humid Southeast, plan on a soap wash every 8 to 10 weeks, because that climate grows mildew on fabric that looks perfectly clean.
The maintenance economics are blunt. A wash costs $15 in supplies and 45 minutes. A replacement vinyl sheet for a 16 ft awning runs $80 to $290 in fabric, plus two people and a half day, or $300 to $800 fitted at a dealer.
When is the awning fabric past saving?
Stop cleaning and start shopping when the fabric fails any of four tests: pinholes you can see daylight through, a wavy stretched front edge that no longer rolls flat, white scrim showing where the PVC coating has separated, or mildew staining that has not moved after two full bleach-and-soak treatments on vinyl.
Mildew that lives inside a delaminated layer is unreachable by anything you can safely put on the fabric, and the stronger chemistry that would reach it destroys what is left of the sheet. The same goes for a tear at the polycord bead: the hem is what carries the load in wind, and a repaired hem tears again at the ends of the tape within a season.
Vinyl typically lasts 5 to 10 years in southern sun and 10 to 15 in the north. Acrylic runs longer on colour and shorter on water repellency. When yours is done, replacing the awning fabric is a two-person job with the roller spring pinned first, and the rest of the exterior maintenance sequence is collected in the roof and exterior hub.
FAQ
Frequently asked questions
What is the best homemade RV awning cleaner?
One quarter cup of mild liquid dish soap in 5 gallons of warm water, which is the same surfactant that branded awning cleaners sell in a jug. For mildew on vinyl fabric only, add 1 cup of 5–6% household bleach to that mix, leave it 10 minutes and rinse hard. For hard-water spotting on either fabric, use 1 part white vinegar to 3 parts warm water.
Can I clean my RV awning with Dawn dish soap?
Yes. Dawn and any similar plain dish detergent is the standard recommendation from awning manufacturers because it is a surfactant with no solvent or degreaser in it. Keep it to a few ounces per bucket. Heavy soap concentration does not clean better, it just leaves residue that mildew feeds on, so the rinse matters more than the dose.
Can you use a pressure washer on an RV awning?
No, on either fabric and at any pressure setting. Around 1,200 PSI is enough to separate the PVC coating from the polyester scrim on vinyl, blow stitching out of a hem, and force the polycord bead sideways out of its channel in the roller tube or the wall rail. On acrylic it drives dirt through the weave and strips the water-repellent finish. A garden hose with an open end is the correct tool.
How do I clean the underside of an RV awning without a ladder?
Lower the arms so the fabric sits at chest height, brush cleaner onto the underside with a soft brush on an extension pole, then roll the awning up wet for 10 minutes. Rolling presses the cleaner against the underside and lets contact time do the scrubbing you cannot reach. Unroll, spot treat what remains, and rinse the underside twice.
Will mildew stains come out of a vinyl awning?
Live mildew comes out with a 1:40 bleach solution and a 10-minute soak, repeated twice. Staining left in the vinyl coating after the colony is dead often does not, especially if the growth sat through a full storage season. If two treatments have not moved a grey shadow, it is pigment damage in the coating rather than growth, and the only fix is new fabric.
How do I get tree sap off an RV awning?
Dab 70% isopropyl alcohol on the spot with a cloth while the fabric is still wet from washing, working from the outside of the spot inward, then wash and rinse that area again. Test on a hidden corner near the roller tube first. Skip bug and tar removers and any citrus cleaner: they take the sap off and the PVC coating or the acrylic finish with it.
Should I clean the awning before putting the RV in storage?
Yes, and the drying is the part that counts. Wash it, then leave it extended until both faces are bone dry, checking the last wrap of fabric near the roller tube. An awning rolled up damp in October comes out speckled with black in April, and that is the single most common cause of mildew on RV awning fabric.
RV owner since childhood trips in a Class C. Mr RV Expert is where I write down what actually works after fixing, replacing and testing the gear myself.
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