Cleaning convertible top? † The top 21 best tips!

17 minute reading time
Cabriodak reinigen? – De top 21 beste tips!
A convertible top is very vulnerable. Don't give dirt a chance by regularly cleaning your hood.

A convertible roof is very fragile and gets dirty quickly. Cleaning a convertible roof is therefore very important. Read the 21 best Tips for cleaning and keeping your convertible top clean here!

Tip 1: Clean the cabriolet roof. Do it ASAP!

Cabriodak reinigen. Doe het zo snel mogelijk

You actually only need lukewarm water to keep your convertible top clean. But don't wait too long with that.​ If you wait, dirt gets the chance to fully adhere to the cloth. It then penetrates deep into the canvas.

It is important to act quickly. Especially with green deposits (algae), bird droppings, rain streaks and fungi.

My advice to you is therefore: do you see that your convertible is getting dirty and do you want to clean your convertible roof yourself? Then brush the hood briefly with lukewarm water and a good brush (Tip #10).

Tip 2: Cabriocap maintenance? It is precisely the UV radiation that causes a dirty convertible top

Cabriokap onderhoud UV straling

The roof of your convertible suffers a lot. This is mainly due to the UV radiation. This UV radiation affects the original protective coating of the convertible cloth. And that can go very quickly.

​​I had various types of cloth tested at Ultramar. These types of cloth are widely used by almost all major manufacturers of boat covers, sunshades and convertible tops. These tests looked at the influence of UV radiation on the original coating of the new fabric. So it wasn't about old, used cloth. But for new cloth. Direct from the manufacturer.​

In almost all cases, the coating had completely disappeared after a few weeks!​ The canvas was therefore no longer protected against dirt, fungi, green deposits, bird droppings, etc. That is also the reason that the roof of a new convertible can become so dirty after a few months that only cleaning with water no longer helps.

Tip 3: Dirt attracts dirt

 Vuil trekt vuil aan
Another important reason to clean the cloth as soon as possible. Dirt attracts dirt.​​

Take green attack now. That well-known attack of algae and mosses. Is there green deposits on your hood? Then dirt can easily adhere to that green deposit. It sort of piles up.​ This green deposit will eventually become increasingly difficult to remove. Because it becomes a combination of green deposits, dirt, fungi.​​ Dirt and green deposits also easily retain moisture. And now let moisture be perfect again for the growth of fungi.​​ So remove dirt as soon as possible.

Tip 4: Regularly clean your convertible top with lukewarm water

Don't give dirt a chance. By regularly washing the roof of your convertible with lukewarm water and a firm soft brush, dirt and green deposits have much less chance of adhering to the cloth.​

A few years ago I was at the marina in Wemeldinge. There I came into conversation with an older man. He was washing his boat cover just then.​ The hood was 12 years old but looked like it was only 1 year old. In all those years he had not used any cleaning products. He had not had the boat cover professionally cleaned.​

There was one thing he did every month. Every month he "dipped" his boat cover with lukewarm water. And if he saw that the cloth was getting dirty more and more, he sprayed the hood one more time with a good impregnating agent. The canvas of a boat cover can be compared to that of a convertible roof.

Tip 5: Cleaning the convertible top with green soap? Do not!

Groene zeep? Niet doen!

I understand it's difficult. There are so many tips to read about cleaning and maintaining a convertible.​ What to believe and what not to believe.

"Just clean your convertible top with liquid green soap. That's safe." says the car salesman. This is a tip from grandmother's time. Grandmothers are often right, but not now. Indeed, green soap is safe. You can be sure that the fabric will not discolour.​ There are also no weird stains by using green soap.

Green soap does have a major drawback. It leaves a kind of greasy film. No matter how well you rinse the cloth, green soap remains will remain in the cloth.​ You can feel it in your hands. If you have used green soap and you rinse your hands afterwards, they will still feel greasy. And you don't want that greasy layer on your convertible roof.​​ Those leftover green soap residues are the perfect breeding ground for fungi, algae and mosses.​ It therefore often happens that a convertible roof becomes green and dirty more quickly after cleaning with green soap.​

Another drawback! The greasy layer makes it much more difficult to impregnate the cloth. The impregnating agent collides with that greasy layer, as it were.

Tip 6: What is a good convertible top cleaner?

I think that a good convertible top shampoo should have a number of properties.

These are the 3 most important.

1: The convertible top shampoo must not collide with the impregnating agent

Impregnation is even more important than cleaning. Impregnation gives the fabric the protection it needs. Prevention is better than cure.​​

Most convertible top cleaning agents are standard cleaning agents. (this is also the case with tent cloth cleaners, etc.). The companies that market these maintenance products often have little practical experience.

They buy a cleaning agent from one supplier. In the other an impregnation agent. A label goes on and from that moment on it is a special maintenance set for the convertible. Those products are just not matched to each other. If, for example, residues of that "special convertible roof cleaner" remain in the cloth, it will collide with the impregnating agent that must be applied later.​​

So at Ultramar I always make sure that products are coordinated with each other. Sprayhood & Tent Shampoo, for example, is made in such a way that if residues remain in the cloth, these residues do not collide with the impregnating agent. Met Sprayhood & Tent Protector.

2: The shampoo should foam well

Many convertible top cleaners hardly foam. That has a major drawback. If you do not see any foam, you also do not know whether the shampoo has already been rinsed properly from the cloth (which is important for impregnation, see Tip 1).

Sprayhood & Tent Shampoo has been foamed extra. As long as you see foam, you will continue to rinse.​​ This will reduce the chance of problems with impregnation in the future.

3: The shampoo must be suitable for every type of cloth.

A convertible shampoo can work fine on a certain type of convertible cloth. But for the other type of cloth it may be much too strong or not strong enough. The shampoo must therefore be suitable and, above all, long-term tested on all kinds of cloths from all manufacturers.

Tip 7: With your convertible through the convertible car wash?

​1: Greater chance of leakage

I don't own a convertible myself. And washing a car by hand is certainly not a hobby. But if I had a convertible I certainly wouldn't go through the car wash. The soft top of your convertible will certainly not leak immediately. But the fabric, the stitching, the construction does take a lot of damage. The risk of leakage is ultimately quite high.

Almost every convertible top is made of fabric that consists of 2 or 3 layers. These layers are glued together. The outer layer is treated with a protective coating by the manufacturer. The cleaning agents used in a car wash can affect the coating. The mechanical load by the brushes or rags is also not really conducive to the coating and the glue used. This will allow the layers to peel off. Ultimately, the cloth will wear extra quickly and start to leak.

2. No control over the washing process

There are special "convertible car washes". This is often a so-called 'rag wash'. Rags are definitely a safer option than the revolving brushes. The only problem is that the machine just finishes its program.

The rags and pressure washer really don't take the condition of your hood into account. Whether the stitching is worse or the fabric is several years old, the machine just does its thing. Then there is the flushing time. That's far too short. You now know how important it is that no cleaning agent remains in the cloth. The machine sprays some water over the hood and rinses the hood. You can be sure that there is still too much shampoo left on the convertible top.

Tip 8: Be careful with the windows​ of your soft top

​The plastic rear window is extra vulnerable

Not only your convertible top is vulnerable. The rear window is also more vulnerable than with a "normal" car. The plastic rear window contains a plasticizer. This plasticizer ensures, among other things, that the pane is somewhat more flexible than, for example, glass.

​After a number of years, the plasticizer decreases. It is then as if the window becomes stiffer, stiffer. This makes the glass more fragile. Sometimes it is as if the glass has become 'milky' and opaque. If you go through the car wash with such a window, the window will certainly tear or break at some point.​​

It is therefore best to clean a plastic rear window by hand with water and a soft cloth. Optionally, you can treat the plastic window with a boat polish or Teflon-based car polish. This gives good protection.

A rear window made of glass

Does your convertible top have a glass rear window? Then you may have also read on the internet that you can go through a car wash with such a hood? A glass rear window is less vulnerable than a plastic rear window, isn't it?

The glass will indeed not tear or break. But the pressure on the glass puts more force on the stitching and bonding. The risk of damage is greater, especially with an older convertible top. The window can come loose.

Tip: Do you also have rear window heating? Make sure that the plug connections do not get wet.

Tip 9: Do not use a pressure washer!

Gebruik geen hogedrukreiniger

Yesterday I received an email from a customer. He wanted advice on cleaning his convertible top. He had bought a second-hand convertible. The old owners had never done anything to the hood. He wanted to clean the hood nicely again.​

He had used the Ultramar Sprayhood & Tent Shampoo for cleaning. (Step 1 of the Step-by-step plan) After cleaning, some dirt was still visible. Especially deeply ingrained dirt. He tried to spray it off with a pressure washer. Often things go wrong there.​ The dirt cannot simply be washed away. So he had to spray closer and closer to the canvas to see an effect. The result is spray marks and in many cases a damaged convertible top

What could he have done better?​ He should have gone on to Step 2 from our Step-by-step plan. Namely, further cleaning with the Ultramar Power Cleaner.​ And give the product time to tackle that pollution as well (see Step-by-step plan).​ He eventually did.

Tip 10: Use the right brush

Utramar borstel

A good brush is very important. If the brush is too soft, it won't do anything. If the brush is too hard, you will damage the top layer and the stitching.

I always recommend using a brush with split ends. ​See photo.​

With this brush you can apply force without damaging anything. Because the points are very close to each other, they hold water and cleaning agent well. This in turn enhances the cleaning effect. Is the brush dirty? Just run it in the dishwasher for a while.

Tip 11: Rinse, rinse, rinse

Spoelen, spoelen, spoelen

 I hear myself repeating it again. But it is also so important. The cloth could have become so clean. But if it is not rinsed properly, it will quickly become dirty again.

Tip 12: Remove bird droppings immediately

Bird droppings on your convertible can be a nuisance. Not just on the paint, but especially on the roof. Bird droppings are acidic. That acid eats into the canvas. This can be clearly seen when you remove the bird droppings. Unsightly light spots can then appear. They can no longer be removed.​

Tip: Make sure that the impregnation is always optimal. Then bird droppings can burn in less and make unsightly stains.

Tip 13: Always a combination of dirt

When you look at a dirty convertible top, you often only see 1 thing. The hood is dirty!​​ But that is almost never due to 1 type of dirt. In almost all cases it is a combination of green algae and mosses. But also mould, bird droppings and atmospheric pollution (for example the well-known rain stripes).​

Tip 14: Help now water is leaking through the seams

After cleaning, it can happen that a convertible top leaks. That is almost always through the stitching.​

The seams are perfectly waterproof for cleaning. The holes are closed by the cotton fibers of the stitching. But also because of all the dirt and old impregnation. When you clean, you remove all of that.​ The result is a stitching hole that is initially more open than before cleaning.

It doesn't matter.​ Spray the stitched seams 1 or 2 extra times with a good impregnating agent. This way you fill the hole again and the hood is watertight again.

Tip 15: Check the stitching of your convertible top regularly

Controleer de stiksels van uw cabriokap regelmatig

The stitching is important. The hood is glued in many places, but in the end it is the stitching that keeps the hood in shape. By regularly cleaning your convertible top, you can quickly see whether the stitching is still good. The stitching can become bad after a few years. Sunlight in particular causes weak stitching.​ Rub your nails over the stitching. This way you can quickly check if they are bad.

Tip 16: Give it time

The effect of cleaning is determined by 4 factors. Together they determine the end result.

  1. Time
  2. Temperature
  3. Mechanical Labor
  4. Chemistry

These 4 cleaning factors are nicely displayed in the Circle of Sinner. By decreasing one factor, the other will have to increase.

For example: ​If you clean the convertible top with cold water, the factor 2: Temperature will be small. Another factor will then have to increase to fill the circle. For example, you have to scrub much harder. (factor 3: Mechanical work)

1: Time

Geef het de tijd
Circle of Sinner 

By allowing the cleaning agent to act longer, the cleaning result will be better. This effect is especially visible with Ultramar Power Cleaner. Feel free to let the Power Cleaner work on the dirt for hours. At Ultramar we spray the Power Cleaner on the dry cloth. On some hoods we leave it on all day. We add a little extra every hour. Then let the time clean it up.

2: Temperature

Cold water works less well than lukewarm water. The water should never be warmer than about 30 degrees. You must be able to put your hands in it well.

3: Mechanical labor

By brushing longer and harder, the dirt will come off better.

4: chemistry

​Is the hood not clean after 1 cleaning? Then spray some more cleaning agent on the cloth and brush it in again.

Tip 17: Not every convertible top is the same

Not every convertible top is the same. There are different types of cloth that are widely used.

Vinyl convertible

This material is a bit like plastic. Think about truck tarpaulin.​

In the past, this material was standard used by most car manufacturers. It was cheap and easy to maintain.​ Today it is used less and less. Due to the strict environmental regulations, the fabric manufacturers are no longer allowed to use certain chemicals.​ As a result, this material is not very durable. It hardens quickly, it discolours and the top layer can easily tear when the hood is folded.

Do you still have such a hood? Then clean it with a good shampoo.​ To protect it, there are good Vinyl protectors on the market.

Woven cloth (Sonnenland®)

Almost all convertible tops are made of this convertible cloth. In the past, it was mainly the expensive brands that used this. It was made by Happich® under the name Sonnenland®. Nowadays Sonnenland® has become more of a generic name. Such as Luxaflex® and Spa®. It is almost certain that your convertible top is made of this cloth. For cleaning this kind of convertible tops you can request our Step-by-step plan here

Tip 18: Do not park your convertible under a tree

Parkeer uw cabrio niet onder een boom

I know it's almost impossible to do. But if at all possible, don't park under a tree! There are birds in that tree. And birds poop :-) See Tip 12.​

But there is more falling from that tree. Wet leaves and berries can cause unsightly stains. Resin leaks from some trees over time. Those resin stains are very difficult to remove from the cloth.

Tip 19: Have the convertible top cleaned

Cabriokap laten reinigen

Cleaning and thorough cleaning of a convertible top does not have to be a difficult job. As long as you work in a few steps and use the right products. I can imagine that you think: yes of course. It's easy for you to talk, Pieter. You don't have a convertible!​ And where should I do that? And when should I do that?

In that case, you can also have the hood properly cleaned and impregnated. There are several good companies that clean convertible tops. In any case, always ask how they clean it and what products they use.

Tip 20: Convertible roof repair or replacement? Don't forget to protect again!

There may come a time when you still need to have the roof repaired.​ Or maybe worse. It needs a new roof. That quickly costs between € 1000.00 and € 2000.00.​ Protect your new or repaired roof immediately. Spray it with a good impregnating agent. This means that dirt, mold and green deposits are less likely to get a chance. You are guaranteed to enjoy your hood for longer.

Tip 21: My most important advice: Impregnate your convertible roof regularly!

I have been the director of Ultramar for almost 20 years now. In all those years I have spoken to a lot of people about the maintenance of their boat cover, tent, awning or convertible roof.​ None of those people thought about the need to protect the canvas. When impregnating, people always thought of waterproofing.​ And you only waterproof if it leaks. That was the thought.

If there is 1 Tip that is most important and always comes back, it is this: Protect with a good impregnating agent. Whether it is a new convertible top or a used one. Whether it leaks or not. Spray it regularly with an impregnating agent. Not so much to make it waterproof. But to protect the canvas and keep it good for a long time.​

Prevention is better than cure!

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Read more about cleaning your convertible top here.