About Your Roof: 

Cleaning

Clay Tiles

Moss, Algae and Lichens grow on the attractive terracotta surface of these tiles. Left untreated, the lichen and black algae will eventually cover the entire roof and slowly breakdown the tile surface. Regular cleaning will extend the service life and improves the appearance of your roof and your home.

How to Clean & Maintain Clay Tile Roofs 

Clay tiles are high quality roofing, with life long durability and a natural colour that is kiln filed into the tile.

Thick algae, moss and lichens will build up on these tiles creating acidic conditions that will degrade the tiles surface, and its appearance, and shorten the service life. Clay tiles require a specific application method and formulation of Bio-Shield to get a good cleaning result.

Once applied, Bio-Shield will kill and remove algae, moss and lichens without harsh water blast cleaning ( no leaks) or washing down, – its a simple, quick and no mess application

The Cleaning Process
A specific formulation of Bio-Shield is applied directly to the tiles to counter the natural resistance to cleaning that clay tiles have.
Once applied to your roof, Bio-Shield will kill all the moss, algae and lichens  within 3 to 4 hours.
You will notice distinct colour changes in the lichens over the next few weeks as the dead growths start to breakdown.
After 2 to 3 months, the cleaning process will be more visible, as rainfall and wind begin to remove the dead growths, revealing more and more of your roofs attractive terracotta colour.
After 12 months,  the roof will be fully clean and can stay clean for up to 2 years.

Maintain your roof with Bio-Shield.
We recommend re- application of Bio-Shield every 2 to 3 years, to keep the roof clean and protected.
Algae or lichen spores and light re-growths will be quickly removed, and the roof will stay clean for another 2 to 3 years.

Water Blast / Pressure Cleaning:
A clay tile roof can be carefully water blast cleaned 3 to 4 weeks after the Bio-Shield application, however this is not required to get a clean roof.
Clay tiles are fragile and can break easily if not walked on correctly, and water will always enter a tile roof when it is water blast cleaned.  Any water blast cleaning will damage and knock out loose mortar. This work should only be carried out by an experienced operator and as part of a full restoration of the roof.

2 Year Guarantee
Bio-Shield applications are covered by a written 2 Year Guarantee

Expert Clay Tile Roof Cleaning

Roof Cleaning Ltd are genuine specialists in Bio-Shield roof cleaning, with over 37 years experience and more than 9700 roofs cleaned and treated with Bio-Shield®.
Expert Application, Proven Performance, Reliable Results

Yes, Bio-Shield has been used commercially and safely for over 37 years and on more than 9700 roofs in New Zealand. It is not acidic, not a bleach and not abrasive like pressure washing, so won't cause any damage to the tiles, pointing mortar, skylights, vents, solar panels or other fittings and fixtures commonly found on roofs.

 A general guideline for the clean up time after initial Bio-Shield application would up to 12 months, if the growths are heavy and well established on the roof.
Older clay tiles can have localised surface damage caused by acidic conditions created by lichens. This results in isolated black marks on individual tiles that are difficult to fully remove.
Other factors that affect clean up times is the pitch of the roof and how much rain falls on the roof once the dead growths have begun to break down.

 Clay tile roofs that have previously been cleaned with Bio-Shield and is having a 2 or 3 yearly maintenance treatment can clean up in a matter of weeks if the growths are light.

Yes, Bio-Shield is water based, water soluble and bio-degradable so it is safe to use on roofs that collect drinking water. The storage tank will be disconnected before application and can be reconnected after a minimum of 3 to 4 weeks and at least one day of rain has flushed the roof clear of Bio-Shield residue.

A diverter can be installed on the tank inlet pipe, on above ground tanks to isolate the water tank form the roof and make reconnection and any future disconnections a 15 second task. No need to remove down pipes or fit expensive and ineffective diverters to the down pipes

We do not recommended cleaning a roof over the summer months, from January to March , in drier areas as there may not be enough rain to flush the roof and refill the tank after it is reconnected.

Clay tile roofs should be treated every 2 years to maintain them in a clean condition. Regular treatments will help to preserve and protect the tiles for damage caused by lichens and algae.

The micro climate around a roof will have a large influence on timing between the maintenance treatments.

If there are trees near the roof, the roof is steep pitched or birds habitually use the roof to rest or nest, annual or 2 yearly treatments may be required to keep the roof clean.

Unfortunately some applications by companies that are not specialists in roof cleaning, for example house wash, gutter cleaners or handymen, are not being done correctly and leaving a patchy clean up from incorrect or incomplete application.
Bio-Shield gives a faster and superior clean up on concrete roofs and roofs treated with Bio-Shield are guaranteed to clean up.

Bio-Shield can not kill plants, it is a surface santizer, not a systemic garden spray or herbicide
It can safely be used on lawns to kill moss and on tree trunks and branches to kill lichen.
In sunny conditions, some delicate leaved plants can get spotting on leaves from contact with Bio-Shield so any affected plants are hosed down after the application.

Edible plants near the roof are always hosed down after the application.
Bio-Shield is fully bio-degradable when in contact with organic matter and soil

The active ingredient in Bio-Shield has been safely and continuously used in the the food industry, in hospitals, veterinary clinics and zoos as a hard surface sanitiser for over 60 years.

The only precautions we take are to move feed bowls and toys away from the roof, and flush the bowls out after the application is complete.

When Bio-Shield is applied to any roof we provide a written 2 Year Guarantee on the effectiveness of the application.

While there are conditions to this warranty, these conditions are common across all roof treatments and cleaning methods as they relate to the situation, pitch and conditions around the roof, not the quality of the application.

You should be aware of the limitations in keeping any roof clean.

More information is provided in the written quote we supply to you.