How do you protect a soft top roof?
Quick answer: Clean the fabric thoroughly and let it dry, then apply a dedicated soft-top weather-proofer (a hydrophobic coating with mould inhibitors). Decant it and brush it in so it soaks through the fibres - sprays sit on top of the weave. Let it cure, keep it dry until it has set, and repeat every season or two to maintain protection and beading.
A fabric convertible roof needs regular weather-proofing to keep water off the fibres and mould out of the weave. Skip it and the fabric soaks up water, stains, and starts to look tired years before it needs to. A car cover is not a substitute -- covers trap moisture and can worsen the problem.
What a weather-proofer actually does
A purpose-made weather-proofer is a hydrophobic coating for fabric that also carries mould inhibitors. It waterproofs the weave, makes rain bead and run off, and stops the hood sitting wet and soggy for hours after a shower.
It also fights the organic side of things. A good coating inhibits the growth of lichen, algae and moss.
Clean the hood before you proof it
Organic matter on the surface looks awful, but it is not what actually damages the fabric. Dirt and grit in the fibres cause the wear. Grind that in and the hood thins and frays at the high-use areas long before its time.
Clean the hood properly first. A weather-proofer applied over dirt seals the grit into the fabric, which is the opposite of what you want.
Which products to use
Hood cleaning kits with a weather-proofer included are widely available. Common ones include AutoGlym, Pro-Kleen and Auto Finesse. Our own preference is Renovo Ultra Proofer, which is the choice of most professionals and convertible roof specialists.
Apply to a dry hood, with a brush
Weather-proofers are waterproof by design, so they will not soak into a damp hood. Make sure the fabric is thoroughly dry before you start.
Many products come in a spray bottle. We do not recommend using the spray. The fabric needs to be fully wetted so the coating soaks through every fibre, and a spray just lays product on the surface. Decant it into a container and work it in with a brush. You get an even coat, better penetration, and far less mess on a breezy day.
Once applied, the coating needs to dry undisturbed. Do not apply it when the forecast says rain - the hood must cure dry or the coating will not set properly.
How often to re-proof
Water beading is the best gauge. When rain stops balling up and starts soaking in, or the hood feels wet rather than damp after a wash, the coating has worn and it is time to re-apply. Keeping on top of this matters most before winter -- a well-maintained soft-top handles a British winter without problems; a neglected one will give you damp carpets and condensation from the first cold week.