Scotland's climate is cool and wet and experiences an average of 250 days of rain per year, whereas the drier parts average 150 days of rain. Rainfall has increased in Scotland by 27% from 1961 this precipitation has risen in the north by 51% and the west by 45% exacerbating the moss problem. The actual rainfall has intensified by over 50% on some of the days it rains this deluge can cause moss to dislodge blocking valleys gutters downpipes. Moss retains around 20-30 times its own weight in water which keeps the roof wetter for longer accelerating tile degradation, these wet conditions allow for faster growth of moss. These living organisms only require moisture, light and minute quantities of mineral salts to grow with vigour on concrete tiles.
When microorganisms settle on an essentially bare substrate they create a more humid chemical microenvironment, they form a biofilm (Domingo et al., 2011), which is followed by the chemical biodeterioration of the substrate. In addition, research (Edwards et al. 1991, Edwards and Seaward 1993, Seaward and Edwards 1997) has shown that lichen thalli produce calcium oxalate which is highly destructive and capable of biodeteriorating some substrates within a relatively short time-scale. Bastidas-Arteaga et al. (2008) suggests that the biodeterioration of substrate is mainly caused by bacteria, fungi, algae and lichens (Cho and Mori, 1995; Gu et al., 1998; Javaherdashti and Setareh, 2006; Nica et al., 2000). Oxalic acid actions, could cause ceramic matrix deterioration and consequently aging of ceramic roofing tile systems.( Kiurski JS1, Ranogajec JG, Ujhelji AL, Radeka MM, Bokorov MT. (2005)
Roof maintenance is essential to prolong the lifespan of the properties roof and some roof tile manufactures suggest a bi annually visual roof inspection of valleys gutters etc., monier.com.au/Roofing-Information/Protecting-and-maintaining-your-roofRoof Cleaning should be considered an essential part of this maintenance program. Roof tile manufacturers recommend not to use high pressure washing whereas the use of biocides and scraping being the preferred method. https://www.marleyeternit.co.uk/Blog/2016/September/How-do-I-remove-moss-or-lichen-from-my-roof.aspxCotec Roof Cleaning use 3 different roof cleaning systems to cover all types of roofing substrates. Low Pressure washing with a biocide treatment is an excellent roof cleaning system and will remove all the dirt moss and lichen from the roof. Moss falls away readily as it does not have a true root system just simple hair-like protuberances, lichen is attached firmly but washes away adequately. The biocide treatment kills any remaining spores on the roof and inhibits regrowth for many years. Algoclear Roof Cleaning & Surfactant Roof Cleaning
Roof Tile Colour Fade
Roof tiles over the years lose some of their original colour this will become evident after cleaning and the degree varies between tiles. The roof cleaning process only removes the biofilm and dirt accumulation not the colour of the roof tiles.
Roof before cleaning
Roof After cleaning
Roof Tile Wear
New Roof Tile with smooth surface. Moss growth can be prevented by the application of Cotec’s premium biocide. Application should be approximately every 3 years depending on location from when the roof is around 4-year-old.
Ludlow 25 year old roof tile where the surface erosion and colour loss can clearly be seen this has been caused by the wind rain sun frost etc.The tile colour after cleaning will be lighter due to the effects of the elements and is not caused by the roof cleaning process. Granular tiles lose their granular finish again due to the effects of the elements over many years.Cotec’s Vortex Roof Cleaning System will not alter the tiles surface finish.