How to soft wash man-made, composite, artificial fibre cement roof tiles (Part Two)

January 23, 2018

Benz Softwash Bio Cleanze DDAC biocide & Benz Softwash Lightning Cleanze SH sodium hypochlorite biocide

A customer asked us for advice on the best way to clean moss from a roof tiled with artificial, man-made fibre cement roof slates.

The problem is that fibre cement slates usually have a surface coating, which can break down over time though natural weathering, or as a result of a poor manufacturing process.

Quick Tips:

1) When the surface coating begins to break down the tiles become more vulnerable and require greater care when cleaning them, when scraping and brushing.

2) Remember to inform your customer that moss falling from roofs leads to rapid colonisation of algae on paths and patios, and that leaving the moss to grow could potentially damage their roof.

We recommend treating man-made roof slates with Benz Bio Cleanze, after manually removing the worst of the moss and lichen.

Bio Cleanze will flow up inside the laps more effectively than other cleaning products, ensuring the growths and spores are killed. In our experience this is the best way to treat man-made roof slates.

Inspect the roof before soft washing man-made slates

It is essential that before softwashing a roof, softwashing contractors inspect the man-made roof slates, and look for existing damage to the coating, during the quotation stage.

It is important to make your customers aware that, through cleaning and treating the roof, the damaged coating underneath, which may have been hidden by the algae/moss, may be exposed.

Your customer needs to understand that the exposed damage is: a) usually only to the surface coating b) the slates will usually still be weatherproof c) the slates can look a lot worse after being cleaned than they actually are d) the treated and cleaned slates can be repainted with whatever colour your customer chooses.

Quick tip: If the slates are under guarantee, the manufacturer will usually have a legal duty to repaint them without charge.

Important steps to take before treating artificial roof slates

  1. Take plenty of before photos.
  2. Explain the situation to your customer, so they know in advance what to expect as a possible result.
  3. Take after photos.
  4. To protect yourself (some customers have short memories when making agreements) ask your customer to sign a statement that they have been told about, and understand the nature of, the treatment, and the possible exposure of prior damage to their roof slates that could come about as a result of a soft wash treatment.

After you've explained the reality of what to expect after a soft wash treatment it's then up to your customer to decide if they would like to go ahead. 

And then even if they don't like the look of their roof after you've cleaned it, you can rest safe in the knowledge that you did all you could to help them make the best decision. And you cannot be blamed for poor workmanship or malpractice.

Can damage to fibre-cement roof slates be repaired?

The damage will usually only be to the surface coating, which can be repainted. And fortunately most of the time the slates themselves will remain sound, so do not need repairing.


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