Maintaining My Home

while slates can make very durable and long-lasting roofs, they can be damaged by people walking on them or using harsh chemicals, so obtain and follow the slate supplier’s or installer’s recommendations for cleaning

if you plan to clean the roof yourself, always let someone else know when you are working at height. Make sure your access to the roof (ladder or scaffolding) is secure and on a stable base

wash the roof with a gentle household detergent and a soft or medium-bristled brush and low-pressure hose. Any water spray should always be directed downwards

to deal with stubborn moss or lichen, proprietary chemical solutions can be applied with a garden sprayer. Different products act at different speeds. Do not expect all moss and lichen to be removed immediately – with some products, the lichen can take several weeks to die and is gradually washed away over months of sun/rain weathering

at the same time as cleaning the roof cladding, check that roof penetrations and flashings remain weathertight and in good condition, and check and remove any debris from the guttering

if the slates are in poor condition or roof access is difficult, consult a specialist roofing or roof cleaning company

clean away moss and lichen as described above

remove branches hanging over the roof. If you are doing this yourself, always let someone else know when you are working at height and ensure pets and children are out of the way. Make sure your ladder or scaffolding is stable and secure and your cutting tools are sharp. With large or heavy branches, remove in stages and avoid letting large branches fall on the slates

for very large or tall trees, trees on steep ground or with branches close to power lines, consider using a professional arborist. Look for an appropriately trained/experienced practitioner, such as an approved contractor of the New Zealand Arboricultural Association