Roof Care Systems


LICHEN, ALGAE & Organic Growths….. A New Maintenance Headache


Mosses, lichens and algae are some of the earliest forms of life on this planet, preceding mankind by millions of years. They have remained relatively unchanged during this period of time and range from simple single-celled algae to the somewhat more complex moss types. These growths cause several problems. They are living organisms which only require moisture, light and minute quantities of mineral salts to grow, however, they can grow on virtually any roofing material or surface. Their root systems have the ability to bore into solid granite up to 12mm. Therefore, once established on tiles, they allow the passage of water into the substrate which gives rise to frost attack and shaling of tiles. These growths excrete acids, mainly oxalic, which attack the alkalinity of materials used, further weakening the tiles and bleaching the colour out. Mosses will grow up under the laps and cause capillary attraction of rain water resulting in leaks that require roof treatments. When the mosses become large they are dislodged by heavy downpours of rain, resulting in the additional maintenance problem of blocked gutters.

Heavy moss contamination when soaked by rain will considerably increase the weight load on a roof. Once established these colonies lead to the rapid deterioration and breakdown of roofing materials eventually necessitating costly replacement.


Over the last decade the incidence of roof contamination from mosses, lichens and algae has increased at an alarming rate. These problems have become so severe in certain parts of the country that some Local Authorities and Housing Associations have roof cleaning as part of their cyclical maintenance programmes.

In 1956 the Clean Air Act was introduced which subsequently reduced the amount of air pollution, and in recent years there has been a general reduction in heavy industries which has given rise to a much cleaner environment. This has resulted in a dramatic increase in the amount of airborne spores. In addition our climate is becoming milder and as a consequence these simple plant forms are able to survive and multiply. Whereas in the past these growths have appeared predominately in rural locations, they have now encroached into inner-city areas and can be seen contaminating some of the most prestigious buildings in the land.


M.G.C. is a unique Company which has specialised for over 36 years in the study of microbial attack on buildings. Based on this experience M.G.C. developed a range of roof moss removal systems and roof treatments to eliminate all types of moss, lichen and algae infections on all varieties of roofs and roofing materials. These treatments will not only eradicate the growths but protect the roofs from reinfection.


A simple, two-stage roof treatment for roofs infected with mosses, lichens and algae.

LICHENITE: A colourless easily applied roof moss killer applied by brush or low-pressure spray to infected areas. It is left on the surface for 72 hours to allow the root structures within the substrate to be killed off. LICHENITE is approved under The Control of Pesticides Regulations 1986 (as amended) for use as directed. H.S.E. No. 7497.

HALOSEAL: A clear, colourless solution of complex stearates which has the ability to protect surfaces against water penetration and prevent the regrowth of mosses, lichens and algae for up to ten years. It can be applied to asbestos, clay and concrete tiles, slates etc. HALOSEAL penetrates into the tiles and protects against further deterioration and does not result in shiny tiles when dry. HALOSEAL is micro-porous and can even be applied when the tiles are damp.


ROOFCOAT FR10 is a one-component polymeric composition for leaking roofs, gutters and similar structures for application in circumstances unsuitable for other coatings.

ROOFCOAT FR10 contains no bituminous products and can easily be applied providing an instant remedy for leaks in all weather conditions thus avoiding Roofing Contractors’ nightmare of a “wash off’.

In emergency situations, ROOFCOAT FR10 can be applied successfully under water and curing will still take place whether it is applied thickly or thinly.

It will adhere to any surface, bitumens, roofing felt, metal, plastic, brick, concrete, tile, slate, timber, asbestos, etc. and, in conjunction with M.G.C. reinforcing membrane, cracks, splits and defective joints can easily be repaired.

ROOFCOAT FR10 is an ideal product for roof repairs when adverse weather conditions prevail and can even be applied in the pouring rain.

One coat can last up to 10 years.