How to Clean Mildewed Outdoor Cushions
The wash order for a rental cushion between guests, from the tag to a foam core that is actually dry.
How to clean outdoor cushions mildew on a tower is a bucket job. The spots are a fungus living on dirt and skin oil in the weave, not a dye failure in the acrylic. Brush the dry film off, wash with mild soap, and rinse on the slab. A hose over the rail in St. Petersburg or Tampa lands on the unit below. Leave the foam damp and Tampa Bay grows the spots back.
How do you clean mildewed outdoor cushions?
Brush the dry dirt off, wash the cloth in a bucket of mild soap, and rinse on the slab. The spots are eating a film. Soaking the foam does not starve them.
Read the tag before you mix anything. Sunbrella mixes apply only when the tag says so. Another cloth, or a missing tag, stops at mild soap.
Lift the cushion so you can see the back and the zipper side.
Brush dry dirt and loose mildew off before water hits the cloth. Wet dirt pushes into the weave.
Mix the soap wash in a bucket. Do not run a hose off the edge.
Work the whole panel with a sponge or a very soft brush, seam to seam, not in a circle on the spot.
Rinse from a second bucket on the slab, then stand the cushion so the foam can drain.
Prepare a solution of 1/4 cup mild soap per gallon of lukewarm water.
Source: Sunbrella, how to clean Sunbrella upholsteryRinse thoroughly to remove all soap residue and allow fabric to air dry.
Source: Sunbrella, how to clean Sunbrella upholsterySoap left in the cloth feeds the next spots. Keep that rinse in the bucket, the same limit as cleaning a balcony without a hose. Hard chairs on the slab are a different surface, on the outdoor furniture page.
If the cover unzips, brush the inside too. That is the side a guest smells.
Why do cushions mildew so fast in Tampa Bay?
They mildew fast because the cloth stays damp and dirty, not because the fiber is food. A cushion facing the water in St. Petersburg, or one tucked into a shaded Tampa lanai, stays cool underneath for days after rain. The top dries. The foam does not.
Sunbrella says its fabric does not feed mildew. Dirt left in the weave does. Skin oil, pollen, and a spilled drink are the meal. A unit empty between guests lets that film sit, because nobody brushes it off midweek.
Pests and organisms, such as mildew and bacteria, may attack organic materials.
Source: University of Florida IFAS, Closing Your Seasonal HomeThat extension publication also calls Florida warm and humid, and a Gulf storm gives the film water. The black film on a rail is a different problem, in the balcony mold and mildew guide.
What is safe on solution-dyed acrylic?
Mild soap and a very soft brush are the ordinary wash. Use the bleach mix only when the tag says Sunbrella. Scrubbing and a hard bristle are off the list, and bleach stays off any cover the tag does not name.
Solution-dyed acrylic is outdoor fabric whose color is put into the fiber before it is woven, which is what Sunbrella sells for cushions that live outside.
It is not permission to attack the weave. Work the whole panel, seam to seam, so you do not leave a ring where the spot was.
To remove mold or mildew: Prepare a solution of 1 cup of bleach and 1/4 cup mild soap per gallon of water.
Source: Sunbrella, how to clean Sunbrella upholsteryThe bleach recipe is for Sunbrella fabric only and may discolor other fabrics. Mix it only when the tag says Sunbrella. Keep that bucket on the slab. A splash on the chair frame is a stain on a different material.
Rails and floor film are a separate job from the cloth. That work is what balcony mildew cleaning covers. Do not pour the cushion mix on the concrete just because you are already out there.
What strips a cushion’s water repellency?
Repeated thorough cleanings, and years of sun, are when Sunbrella says you may refresh the cloth with a retreating agent. They do not name a household product that strips the finish, so this page will not invent one. What they forbid is scrubbing.
Avoid scrubbing, hard bristle brushes or any other abrasive cleaning method.
Source: Sunbrella, how to clean Sunbrella upholsteryA hard brush lightens the spot while you are still working, and it roughs the yarns that shed water. Rain then sits in the nap, and the foam stays wet longer.
| What you do | What the maker allows | What happens to the cloth |
|---|---|---|
| Mild soap, soft brush, air dry | Their ordinary wash | The method they publish |
| Their bleach mix, tag confirmed | Mold section, their fabric only | May discolor other cloth beside it |
| Hard bristle or a scrub | They tell you to avoid it | Roughs yarns that shed water |
| Years of full washes in the sun | You may retreat the fabric | Their refresh is a retreating agent, not a hose |
What a cushion wash does to the finish, from Sunbrella’s cleaning page
If the tag is missing and the spots are in the foam, text a photo before you buy a new set.
Text a cushion photoHow do you dry a cushion so mildew does not return?
Stand it on edge, unzip the cover if the maker allows, and leave it in moving air until the foam is no longer cool in the middle. Mildew returns when the core stays wet. The wash did not fail. The dry did.
The key to mold control is moisture control.
Source: EPA, mold moisture guidePress the center. If it is cool, it is still wet. On a closed lanai in downtown Tampa or St. Petersburg, the screens hold humid air. Open them, or bring the cushion inside the slider until the core is dry. Screen work on that enclosure is on the lanai cleaning page. It does not dry a foam core.
Sunbrella says the fabric should only air dry. Do not use a hot dryer to beat a checkout, and do not aim a hose at the cushion to finish the rinse. That puts water back into the foam.
When is a cushion beyond saving?
It is beyond saving when the foam stays damp or sour after a real wash and a full dry, or when the cover is split, thin, or already bleached to another color. Another soap pass will not rebuild yarn. On a rental, that cushion is what a guest sits on and then mentions.
Replace the set before the next arrival if the smell is in the core. Bay Balcony does not sell cushions. The visit prices the floor they sit on: two dollars a square foot of floor, cushions on that floor included, so eighty square feet is $160. No trip fee in either downtown. A cover that powders when you pinch it is finished.
The cushion that looks clean on top and stays cool underneath speckles again before the next check-in. Dry the foam, or you washed the cover for nothing.
Frequently asked questions
Can bleach go on every outdoor cushion?
The bleach recipe is for Sunbrella fabric only and may discolor other fabrics. Read the tag before you mix it. A missing tag means mild soap only, and the wash stays on the slab.
Are the cushions a separate charge?
Bay Balcony prices floor area at two dollars a square foot, and cushions on that floor are included. Eighty square feet comes to $160. There is no trip fee in either downtown, St. Petersburg or Tampa.
Can I rinse the cushions over the rail?
Do not send cushion rinse over the rail. Water leaving a Tampa or St. Petersburg tower falls on the unit below. Use a second bucket on the slab, wipe the soap out, and let the cushion drain there.
How long should the cushion dry in Tampa Bay?
Stand it on edge so the foam can drain, and leave it in moving air until the core is no longer cool. A closed lanai holds damp air, so a cushion dried behind shut screens often grows the spots back. Sunbrella says the fabric should air dry.
What if the smell returns the next morning?
A smell that comes back after a full soap wash and a dry core is in the foam. Washing the cover again will not fix a core that stayed wet overnight. Replace that cushion before the next guest.
Will more pressure get the spots out?
More pressure is the wrong move on a tower, and Sunbrella rules out scrubbing and hard bristles. Use a sponge or a very soft brush, seam to seam. If the cloth is already split, force only opens the tear.
Sources
- Sunbrella. How to clean Sunbrella upholstery. global.sunbrella.com
- EPA. A Brief Guide to Mold, Moisture and Your Home. www.epa.gov
- University of Florida IFAS Extension. Closing Your Seasonal Home. ask.ifas.ufl.edu