The cost of roof cleaning will be at least £800 for a small bungalow, and with some companies over £2000, so getting the timing right is key.
If your roof has a build up of lichen then this has probably occurred over the long-term. Once lichen is cleaned from the roof it will normally take many years for it to re appear in significant quantity. If your roof is covered in moss this is different as moss tends to grow more quickly and especially so in damp conditions.
When it comes to cleaning lichen from the roof then almost any time of the year is ok providing the weather is dry and the temperature above freezing,
For moss removal it is different. First of all it is best to wait until the latter part of winter or spring before having the moss removed. This is because with the onset of dryer and warmer weather the rate of moss growth reduces markedly, thus any remaining spores are less likely to re-grow quickly.
Applying a fungicidal wash to the roof will kill of any remaining spores but this needs to be applied in the right weather conditions; namely dry weather with a temperature of at least 4 degrees above zero and ideally 6 or more degrees above. The temperature is key as if it is too cold the fungicide will have less effect on killing off the moss and algae spores.
So when is the best time for moss removal? We would advise from late March through to September, although other times of the year are ok providing the weather conditions are suitable.
