Care: Cleaning the soft top - how to remove mould stains and algae

Unfortunately, green soap and scrubbing do not help when cleaning the soft top. The cloth soaks through in the rain, dries slowly and no longer protects the cockpit properly. This encourages further infestation by mould and algae. Thorough cleaning and new impregnation are necessary - either by yourself or by a specialist.

Professional cleaning: Expensive, but thorough

One option is to have the soft top professionally cleaned by a boat builder or saddler. As a rule, the boat builder or upholsterer will pass the soft top on to a specialised dry cleaner. The prices depend on the weight of the tarpaulin.

Cost example:

• Canopy for a ten-metre boat (approx. 3.5 kilograms): approx. 270 euros
• Duration: Up to four weeks (including return transport)

If you want to succeed faster and save costs, you can take the initiative.

Cleaning the soft top yourself

Cleaning takes place in three steps: pre-cleaning, mould stain removal and impregnation. The time required should not be underestimated - the drying times between the work steps alone will keep you busy for a good two days.

DIY costs:

• Special cleaner, mould stain remover, impregnation: approx. 100 euros
• Savings compared to professional: approx. 170 euros

Step 1: Pre-cleaning - remove surface dirt

First remove any superficial dirt. To do this, soak the soft top in warm water. A home-made basin made from four 2.5 metre long and ten centimetre high boards and a fabric tarpaulin is ideal for this - much more practical than a bathtub.

1. Soak the cloth in warm water (20-30 minutes)
2. Spray special cleaner (e.g. from MTS mould service or Ultramar) onto the damp cloth
3. Work into the fabric with a soft brush
4. Approx. 20 minutes exposure time
5. Rinse thoroughly with water

Result: The fabric becomes cleaner, but algae and mould stains do not disappear completely. Further steps are necessary.

Step 2: Combat mould stains and algae

The intrepid use diluted sanitiser (sodium hypochlorite) to combat spores and algae. Although this works, it harbours risks: The effect is difficult to control and cotton threads are often used for the seams. The natural fibre swells when wet and ensures rainproof seams. However, the aggressive chlorine compound damages the cotton and significantly shortens its lifespan.

Better: special cleaners for soft tops

• Tarpaulin cleaner comparison test

Products such as Tentoclean from MTS mould service or the Power Cleaner from Ultramar have been on the market for decades and have been tried and tested thousands of times. When used correctly, the risk of excessive seam wear is significantly lower.

Instructions:

1. Power Cleaner evenly onto the dry Spray on cloth
2. One hour exposure time
3. Check: Are mould stains significantly reduced? If so, spray on a second portion of Power Cleaner
4. Wait until algae and spak are no longer recognisable
5. Rinse the cloth thoroughly with running water

Result: Even heavily soiled grip areas look like new again after drying.

Important for light beige cotton blend fabrics:

According to Gerhard Macht from the mould protection service, ferrous deposits can form in the fabric during the production process. These tend to discolour when mould stain removers are used. He therefore recommends pre-treatment with his fibre protection agent. Other colours or pure synthetic fibre cloths are not critical. Canopy fabrics are usually dyed to be UV-resistant. There is therefore no need to worry too much about discolouration.

Step 3: Impregnation - protection against new infestation

A good impregnation not only makes the fabric waterproof - it is at least as important to prevent the fabric from becoming damp so that it can dry quickly. The water protection also has a grease-repellent effect. This makes the fabric easier to clean, and algae and mould find fewer nutrients.

Instructions:

1. Impregnation can be sprayed, brushed or rolled on (most evenly with a roller)
2. Start on the inside
3. Allow to dry
4. Treat the outside (the impregnation has already penetrated the seams - the cloth no longer absorbs anything there)
5. Allow to dry thoroughly (at least 24 hours)
6. Water test: Does water roll off? Then the impregnation works

Important:

• Hood must lie flat
• Always process both sides
• No cleaning agent residues in the cloth (otherwise the impregnation will not adhere)
• Observe drying times
• Do not wet the windows! If something does spill, wipe it up immediately with a damp microfibre cloth - never allow it to dry.

High-quality impregnations can also withstand washing. However, they wear off due to mechanical stress when folding the fabric, hail and heavy rain. The protection must therefore be renewed every two to three years.

Why are algae and mould stains so stubborn?

Gerhard Macht from the mould protection service gives reasons for the increasing problem: "The stricter biocide guidelines prevent the effective finishing of the substances." If the storage conditions are not ideal, the material starts to develop mould at the manufacturer Spak. Moulds feel at home at 60 percent moisture - a level that is quickly reached when covering in spring and late summer. The strong temperature fluctuations then cause a lot of condensation.

Maintain the discs too

Soft top windows are sensitive. Water stains and dirt can be removed with Vuplex gently. Spray on and polish with a clean microfibre cloth - even light scratches will disappear.

Time and costs at a glance

DIY: Clean the soft top yourself

• Time required: Two days (incl. drying times)
• Cleaning agent costs: approx. 100 euros

Professional cleaning (Zonklaar or similar):

• Time required: Up to four weeks (transport + cleaning)
• Costs: approx. 270 Euro

Savings DIY: approx. 170 euros

Cleaning your soft top yourself saves a lot of time and money - with a little patience and the right cleaners, the results are impressive.

More about cleaning:

• The best care and cleaning products for yachts
• Cleaner for a shiny boat