Domakihub How to Clean a Canvas Awning and Remove Mould & Salt
A step-by-step method for safely washing retractable awnings without stripping the waterproof coating.
Reviewed by Domakihub cleaning pros · 2026-06-23 · 5 min read
Canvas awnings on Greek terraces and balconies take a beating — coastal salt spray, intense UV, and the damp winters that follow create ideal conditions for mould, mildew, and stubborn mineral deposits. The video above demonstrates the core washing technique, and the steps below adapt it to the specific challenges of homes, holiday rentals, and hotels in Greece. Follow the sequence carefully and your awning fabric will come back clean without losing its water-repellent finish.
Why Canvas Awnings in Greece Need Special Care
Retractable awnings made from acrylic or polyester canvas are coated at the factory with a water-repellent finish — typically a fluoropolymer or silicone treatment baked into the weave. Harsh scrubbing, bleach-heavy products, and high-pressure washing all degrade that coating, meaning the next rainstorm soaks straight through instead of beading off. Getting the cleaning chemistry right is as important as the physical scrubbing.
Salt air is the sleeper threat that most property owners in coastal Greece overlook. Fine salt crystals accumulate in the fabric weave, and when humidity rises they absorb moisture, keeping the canvas damp longer than it should be. That trapped moisture is what feeds mould colonies. A rinse-focused approach — not just scrubbing — is therefore essential in maritime climates from the Aegean islands to the Ionian coast.
What You Will Need Before You Start
Gather everything before you extend the awning: a soft-bristle brush (a long-handled deck brush works well for wide awnings), a bucket, mild pH-neutral soap or a dedicated canvas cleaner, white distilled vinegar for mould, and clean water for rinsing. Avoid wire brushes, stiff nylon scrubbers, and any cleaner that contains bleach, acetone, or petroleum solvents — all of these attack the waterproof coating and can cause the canvas colour to fade unevenly under Greek sun.
If the awning has motorised arms, confirm the power is off and the fabric is fully extended before you begin. Working on a partly retracted awning risks folding dirty water into the cassette housing, which can seed new mould inside the mechanism where you cannot easily reach it.
Step-by-Step Cleaning Process
- 1
Dry-brush loose debris first
With the awning fully extended and dry, use the soft-bristle brush to sweep away loose bird droppings, dust, dried leaves, and surface mould spores. Always brush from the high point down toward the valance so debris falls clear of the fabric rather than being pushed back into the weave. Doing this dry prevents grime from turning into a paste the moment water is applied.
- 2
Pre-treat mould and salt deposits
Mix equal parts white distilled vinegar and cold water in a spray bottle. Spray liberally onto any dark mould patches, green algae streaks, or white salt crust and allow it to sit for ten to fifteen minutes. Vinegar is acidic enough to break down both calcium-based salt deposits and the cell walls of mould without harming the fabric coating — a combination that purpose-built canvas sprays replicate at higher cost.
- 3
Wash with mild soap solution
Dissolve a small amount of pH-neutral soap (or dedicated canvas cleaner) in a bucket of cold water — never hot, which can cause shrinkage in natural-fibre blends. Working in sections from one edge to the other, apply the solution with the soft brush using light circular strokes rather than hard back-and-forth scrubbing. Pay extra attention to the fold lines where the awning retracts, as these creases accumulate grime and are the first place mould reappears.
- 4
Rinse thoroughly with low-pressure water
Use a garden hose on a gentle shower setting — not a jet nozzle and not a pressure washer. Rinse from the top of the slope downward, flushing the soap and loosened dirt completely off the fabric. Insufficient rinsing is one of the most common mistakes: residual soap film attracts dust, reduces water repellency, and can itself harbour bacteria. Continue rinsing until the runoff water runs completely clear.
- 5
Allow to dry fully before retracting
Leave the awning fully extended in open air until the canvas is bone-dry — typically two to four hours on a sunny Greek day, longer in humid or overcast conditions. Retracting damp canvas into the cassette is the single fastest way to trigger a new mould outbreak because the fabric is sealed against itself with trapped moisture. Once dry, consider reapplying a silicone-based fabric water repellent spray (available at most hardware stores) to restore the factory waterproof finish, especially if the awning is more than two seasons old.
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FAQ
- Can I use a pressure washer on my canvas awning?
- No. Even a medium-pressure setting strips the waterproof coating from the fabric surface and can force water into the seams, causing delamination. A standard garden hose on a gentle shower setting provides more than enough water flow to rinse the canvas clean without causing damage.
- How often should I clean an awning in a coastal Greek location?
- Aim for a thorough wash twice a year — once in spring before the heavy-use season and once in autumn before winter storage or the first rains. If the property is within a kilometre of the sea, add a quick rinse with plain water every four to six weeks during summer to flush accumulated salt before it has a chance to hold moisture and feed mould growth.
- The mould has come back after cleaning. What am I missing?
- The most likely cause is either retracting the awning before it was fully dry, or an exhausted waterproof coating that lets moisture linger in the weave. After your next clean, apply a silicone or fluoropolymer fabric protector spray to restore the repellent finish. If the awning is retracting against a wall or the cassette housing is poorly ventilated, consult a specialist — trapped condensation inside the housing will re-inoculate the fabric no matter how well you clean the outside.