How to look after a convertible roof

If maintained correctly, a convertible roof could last the whole life of the car, but without the correct care, it may only last years.

If you have bought a car, new or used, that has a convertible roof, the first thing we would recommend is to familiarize yourself with the roof. Have a look in the manual, learn the controls, see if there is anything in there about maintenance, and if not, maybe do a search on YouTube.

A roof has hinges and perhaps motors which need to be maintained, and may require a dab of grease now and again. It's also important to know that a convertible roof will have drainage. Water will run from it into cutters and scuttles, which will have drainage holes that allow water to flow away through the bodywork, usually in front of the rear wheels. Most people aren't aware of this because it's all carefully hidden inside the trough where the hood folds away when it's down. These areas can get blocked which, while not doing any harm to your hood, can cause leaks into your car, and nobody wants a car full of water.

While we are on the subject of leaks, now is the time to note that your car doesn't have frames around the windows and no door pillars. This means all the glass wear is pressed up against the rubbers.  If these rubbers aren't kept clean, there won't be a good seal and water can leak into your car.

Keeping the fabric roof clean

It is important to note that unless you have a very old car from the early 1970s, the hood isn't supposed to be waterproof, there is a neoprene membrane underneath the fabric which keeps the water out. The fabric part of the hood is largely cosmetic, and all you have to do is keep it clean and dry.

There are several problems with hoods.

1. Dirt, dust and grit trapped in the fibres is abrasive and will cause wear when the hood folds, at the points where it folds, causing permanent damage.
2.  This dirt is a fertile substrate for things to grow in, once wet as rain water will provide all the nutrients for moss, and lichen.
3.  We have found that while the hood its self is not prone to rot, the stitching that holds it together can be. 
4. While the synthetic materials that make up your hood are largely UV stable, without some degree of protection, they will be prone to fade over time.

You would say that, wouldn't you!

We would recommend, that if your hood is already full of dirt, and you can see moss and other things growing on it, that you get it professionally cleaned.  You can clean it yourself, but it is hard work and time-consuming, and difficult to do well.  For the purpose of this article, we will assume you already have a hood in good condition, and you want to keep it that way.

Thought for the day!
You will wear your clothes for a day, and put them in a washing machine for a 50-minute cycle. You know you can't just throw some laundry detergent at them, and they will become clean. Your washing machine is giving every bit of them a thorough clean for almost an hour. Meanwhile, your cabriolet hood is outside for months and has things growing on it. 

What is the best product for cleaning convertible roofs?

We don't think it matters that much. If you are trying to revive a really dirty hood, it helps if your detergent has a bit of bite, but for general maintenance, it's not really needed. In fact, assuming your hood has a coating on it, you don't want anything too harsh that will damage it.  So, a normal car shampoo is probably best, one which has neutral PH and creates lots of foam and bubbles.

These bubbles are helpful because the foam is white and will show you if the hood is clean. If you are rinsing off the hood and the soap looks brown or green, then the hood is still dirty, and you need to keep going until the soap runs away bright white.

We recommend you wet the hood, put on some shampoo, and then use a soft brush to agitate the surface and loosen up any grit. Then rinse off the soap with lots of water.

Pressure washers are a really bad idea!

Not all pressure washers are made equal. The kind of pressure washer that you might have at home is limited by how much water they can pump out by your hose pipe. They aren't putting out any more water, they are just pressurizing it.  

The pressure washers we have are fed with water from a plant room and put out huge volumes of water at a lower pressure, but even they can damage your hood if you get them too close. A pressure washer can cut right through your hood and will certainly mark it by roughing up the surface.

In summary, you want a large volume of water to wash away the grit you have loosened with brushing, but you do not, ever, under any circumstances want to try to blast it out with a pressure washer. You are far better off using a hosepipe with a nozzle, as this won't do any harm.

This will be enough to keep the dirt and dust at bay, and without this, you shouldn't get any green moss, algae or lichen. It also helps if your water repellant coating is working so that the hood dried quickly.

How do I know if the waterproof coating is still working?

When the coating is new, you will be able to see the water bead up and just roll off. You'll be in no doubt that it's working. However, after a few months, dirt and dust will settle on and in your hood and this will break the surface tension. When it rains you will no longer get this beading, instead the water will soak right through the fabric. However, this doesn't mean the waterproof coating isn't still working!

You will still find that if you place your hand on the hood after it rains that your hood is practically dry.  This is how you test your coating, as long as it is only damp, you know you are still in good shape. If, however, you feel your hood, and it's sopping wet, then it's time to get it re-waterproofed.

Sorry!

If you came here looking for trade secrets, tricks or some magic formula, we are sorry to disappoint you. There aren't any. That's it. Give it a good brushing with soapy water, rinse it off with lots of water, do it regularly, keep on top of it. Keep the gutters clear and the rubbers clean, and check the waterproof coating is still intact.

We would recommend it to anybody, but it is also worth having a little kit in the boot of your car for dealing with bird mess. It isn't good for your hood or your paintwork, and it's a good idea to have a bottle of soapy water, so you can wash it off at the earliest opportunity. 

You can make your life a little easier by keeping your car garaged or in a car port, but we would advise against car covers. 

Cats!

The only secret that we can reveal is that pet repellant can work.  Don't let your cat, (or somebody else's cat) sleep on your fabric hood. We know it's comfy and gets warm in the sun, but having it covered in cat hair is an extra problem you don't need.

Give your hood a light dusting of pet repellant spray, and it will stop some cats using your car for sunbathing.

Not all cats, but some.