I’ve been a little quiet on here since joining a year ago. Acquired my Z3 a year ago and have done a number of jobs to recommission the car and in the process had some successes with products that I think are worth passing on to the community. Amongst those has been the use of Protex Canvas Cleaner, Restorer and Waterproofer; I’ve been very impressed with both the improvement in appearance of the roof and the effectiveness of the waterproofing. The restorer brought the roof colour back to a fresher looking black with almost no faded patches, may be worth applying the restorer next year to deal with the small number of remaining faded patches. In terms of waterproofing it has been highly effective and has worked well through a rather wet English spring and summer; rain water even in the heaviest down pours pills and runs off the roof.
Restoring and waterproofing canvas roof
- Thread starter DaveD
- Start date
That’s an interesting point of view and would appear be in contradiction to the general industry approach and advice that supports the approach of waterproofing canvas hoods to maintain them. I also haven’t been able to find any published material from BMW recommending not to waterproof the canvas hood and to the contrary I have found them selling branded products for waterproofing (including a kit complete with cleaner and bucket). Can you please reference the BMW or industry source of the advice not to waterproof? Thanks
Just ask anyone who sells and fits soft tops. They will tell you it is their main source of income. Snake Oil springs to mind.
Tony.
Tony.
You are welcome to waterproof your roof and I am sure all those companies selling waterproofing products would love you too as well. I am just saying the canvas roof never came out of the factory with a waterproofer applied to the canvas , that’s not how it was designed to work.
The canvas deteriorates over time (through environmental ageing of the synthetic fibres from pollutants, UV and heat) and looses the capability to effectively pill water, as intended, and therefore cleaning and applying a waterproofing agent restores this capability to the hood so it functions as originally intended. Also lifts the appearance of the car. All for a relatively small cost and minimal amount of effort.
I did mine this year with renovo dye and fabsil waterproofer. It was in a bit of a sorry state and I was getting a few drips find their way through the canvas. It's now fine. I wouldn't use waterproofer on a newish top but on a 25 year old top I had nothing to lose.
- Joined
- Feb 18, 2016
- Points
- 231
- Model of Z
- Z3M Imola and Z4 (e89)
Adding a repellent won't make your roof waterproof, the membrane does that. If its leaking through the material then the membrane is holed. There is the argument the cleaning and then adding a repellent will keep it cleaner longer, who knows. I suspect most people do it for an aesthetical reason, but there is no maintenance reason for adding it.
A friend of mine has been working with Hartz Stayfast (the fabric that BMW and just about every other OEM use for convertibles) for about 30 years and he 100% states that you should NEVER waterproof a canvas roof.
It is designed to absorb and wick water away - not repel it and bead it away.
I owned a smart roadster convertible for 15 years - the average lifespan of the canvas roof on those cars is about 7-8 years before they shrink and fail. I never once waterproofed mine - and it lived outside uncovered in all weather all year round. After 15 years the roof still looked like new with zero shrinkage.
As said, use what you like but the fibres in the roof break down if they dry out too much and that's irreversible damage.
Why do companies sell repellent if it's not needed? Simples - people *think* it's a good thing - and whatever sells makes money for them.
99% of customers will never own the car long enough to find out the damage it's done - they smile seeing the water beading & running off and congratulate themselves for looking after their roof.
It is designed to absorb and wick water away - not repel it and bead it away.
I owned a smart roadster convertible for 15 years - the average lifespan of the canvas roof on those cars is about 7-8 years before they shrink and fail. I never once waterproofed mine - and it lived outside uncovered in all weather all year round. After 15 years the roof still looked like new with zero shrinkage.
As said, use what you like but the fibres in the roof break down if they dry out too much and that's irreversible damage.
Why do companies sell repellent if it's not needed? Simples - people *think* it's a good thing - and whatever sells makes money for them.
99% of customers will never own the car long enough to find out the damage it's done - they smile seeing the water beading & running off and congratulate themselves for looking after their roof.