A fabric roof is a woven textile with a waterproof backing and a factory-applied water repellent finish. Cleaning it like paint — or worse, like an alloy wheel — strips that finish and leads directly to a roof that soaks through.
What not to use
- Car shampoo. It leaves residue in the weave that attracts dirt and holds moisture.
- All purpose cleaner at strength. Strips the water repellent finish.
- Wax, sealant or quick detailer. They block the weave and go blotchy.
- Pressure washers at close range. They drive water through the fabric and can damage seams.
- Stiff brushes. They fray the weave.
The right sequence
- Vacuum or brush the roof dry first. Removing loose grit, leaves and moss before adding water is the step that matters most.
- Rinse gently with a hose, never a close-range jet.
- Apply a dedicated fabric hood cleaner and agitate with a soft brush, working across the roof in overlapping passes.
- Rinse very thoroughly. Residue left in fabric is what causes staining later.
- Let it dry completely. Fully dry, in the sun or a warm garage. Do not fold a damp roof.
- Re-proof it with a fabric protector made for convertible roofs.
Re-proofing is not optional
Cleaning removes the repellent finish along with the dirt. If you clean and stop there, the roof is now more absorbent than before you started. Re-proofing is what restores beading and keeps water out.
Apply it to a completely dry, clean roof, in even coats, with the roof up and the car somewhere it can cure undisturbed. Mask the glass and paint around the edges — overspray on glass is a nuisance to remove.
Green mould and algae
Common in the UK, especially on cars parked under trees or left standing over winter. It needs a product formulated for it rather than scrubbing, which just drives the spores deeper into the weave. Treat it early — established growth stains the fabric permanently.
Ongoing care
- Never fold a wet roof away. That is how mould starts and how creases set permanently.
- Clear leaves out of the roof channels and drains. Blocked drains are the most common cause of a leak blamed on the fabric.
- Avoid automatic car washes entirely. The brushes fray the weave and the detergents strip the proofing.
- Check the beading. When water soaks in rather than sitting on top, it is time to re-proof.
Glass and plastic rear windows
Older plastic rear screens scratch extremely easily and yellow with age. Use a plush cloth and a product made for plastic windows — never a standard glass cleaner, and never an abrasive. Once scratched, they do not recover.
Before you start
Always read the label on the product you are using and follow the instructions on it for dilution, application and safety. Work in the shade on cool paint, and test anything new on a small, hidden area first — particularly on trim, wraps and finishes you are not familiar with.
Not sure which product fits the job? SWAG Fast Lane asks three quick questions and puts the right kit together for you.