Should I weatherproof a new roof?
Quick answer: Yes -- weatherproof a new roof. You can't be sure how much factory protection it has (some have little or none), and an extra coating won't harm it. We recommend a long-lasting two-year soft-top coating; if you've just had a new roof kit fitted, treat it soon after so it sheds water from day one.
A new convertible roof may or may not come with decent weather-proofing on it. You won't know until the first heavy rain -- and by then, if it doesn't bead, the fabric has already soaked up water it didn't need to.
Why factory protection is a gamble
Factory protection on a soft-top varies enormously. Some roofs come well coated from the manufacturer, others have almost nothing on them. There's no label on the hood telling you which you've got, and two cars of the same model built months apart can behave differently once the rain arrives.
- Some manufacturers apply a water-repellent finish at the factory; others ship the hood with only the base fabric treatment.
- Transport, storage and the time the car spent on a forecourt can all degrade whatever was there.
- The first owner has no easy way to test it short of waiting for rain -- and by then the fabric is already wetting out.
What a proper weather-proofer does
Adding a proper weather-proofer over the top does no harm, and it guarantees the hood starts life shedding water properly. The coating we use is a hydrophobic coating designed specifically for fabric; it soaks into the weave rather than sitting on top, so you still see the original texture.
- Causes rain to bead and roll off rather than soak in.
- Reduces the grip that algae, lichen and mould get on damp fabric.
- Makes routine cleaning easier, because dirt sits on the surface instead of wicking in.
Why we recommend the two-year coating
We put ceramic coatings on the paintwork of a lot of brand-new cars, and a fair number of them are convertibles. Whenever we do, we recommend putting a two-year coating on the hood at the same time. It takes the guesswork out of what the factory did or didn't apply, and it synchronises the protection on the rest of the car with the protection on the roof.
After a replacement roof kit
The same applies after a replacement roof kit. If a customer has come to us with a hood beyond restoration and gone on to have a new one fitted, we ask them to bring it back for treatment once the new fabric has settled. That way the coating goes on clean, untouched fabric, cures properly, and starts protecting the roof before it has seen a winter.
- Wait for the fitter's own curing and tensioning period to finish before coating.
- Clean gently if needed -- new fabric shouldn't have ground-in dirt yet.
- Book the coating for a dry spell so the product can dry without interruption.
Common mistakes with new roofs
- Assuming a brand-new car must be fully protected -- then discovering otherwise in a downpour.
- Applying a wax or paint sealant instead of a fabric-specific product -- the chemistry is different.
- Waiting until the roof looks dirty or green before treating it -- by then you're restoring, not protecting.
- Using a pressure washer on a coated hood and stripping the protection off -- the same applies to automated car washes, which carry harsh detergent that is not suited to fabric.
When a new roof doesn't need treating straight away
If you can see water beading tightly off the fabric in heavy rain and the hood is drying quickly afterwards, the factory finish is doing its job for now. Keep an eye on it -- the first sign the coating is wearing thin is that water starts to darken the fabric instead of rolling off. At that point, book a treatment before the next wet season.