Autumn – season of mists… and slippery block paving!

Category: Steam cleaning

Autumn and winter is when algae, moss and lichen growth is most significant (although build-up can occur during any wet period or in shady, humid areas) and they often grow on hard surfaces such as block paving or flag stones. While they do not damage the stone, they can become very slippery and make pathways and steps extremely hazardous.

Cause

Algae, lichens and moss thrive in damp places as they need moisture for both growth and reproduction – they often appear in sheltered or shadowy areas. Poor drainage conditions contribute to the growth on paths and hard surfaces.

Prevention is better than cure

Property owners are required by law to take measures to ensure the health and safety of visitors to their premises and this includes dealing with any slippery surfaces. It should really be a matter of good sense as no one wants to deliberately endanger their guests, employees or visitors. Having your block paving cleaned will remove slippery lichen, moss or algae and show that you are taking measures to make your premises safe. On a more serious note if someone does slip and injure themselves badly they may take the matter further - in today’s litigious society a fall can easily end up in court with legal fees and damages to pay.

Control

Where algae, lichens and moss are a slip-hazard the following non-chemical controls are recommended.

• dislodge moss from between paving by running a sharp knife along the cracks.
• use a block paving brush with a long handle, narrow head and wire bristles for effective cleaning
• jetwashing is one of the fastest and most efficient ways of removing moss and algae. Steam cleaning means that soft stone can be cleaned without damaging the surfaces. No chemicals are needed and the results are spectacular.

Future prevention

• cut back overhanging plants to improve air flow and allow the sun and wind to dry the site
• ensure surfaces slope slightly to prevent standing water
• improve drainage in the surrounding area will also help to deter growths
• opt for permeable paving when constructing new hard surfaces
• use surface finishes that are raised to give grip in wet weather especially in shady spots.

More about algae, lichen and moss

Algae: A green film or powdery deposit is typical of algae on paving and stonework. The dark green or blackish jelly-like growths that often appear in damper, cooler weather on paths and areas of tarmac are sometimes called blue-green or gelatinous algae, but are in fact a cyanobacteria called Nostoc.

Lichen: Are common on paved areas. The colour varies with species, but most are silver-grey, grey-green, yellow or orange. They can be crust-like, leafy or scurfy in texture.

Moss: Mosses commonly found on hard surfaces are usually cushion-like.

For more information about our cleaning services contact Max or Andy Morris on 0333 234 1445 or email your enquiry and we will get back to you as quickly as possible. 

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