What is self cleaning glass?
Self-cleaning glass is a specific type of glass with a surface that keeps itself free of dirt and grime. Self cleaning glass has a protective coating on the outside of the glass that acts as the ‘self-cleaner’. It uses an organic process whereby dirt is broken down by daylight and is then washed away by rain.
Self-cleaning glass is not a magic solution, but a welcome advance in technology. And like a lot of new technology, it is amazing, but it’s not cheap and does have some limitations. Self-cleaning glass in the UK came about thanks to an intensive research and development programme by the glass manufacturer, Pilkington. Pilkington’s call their self cleaning glass range Pilkington Activ and Guardians range is called Guardian BioClean.
How does self cleaning glass work?
The first stage of the cleaning process is “photocatalytic“. In this stage the coating reacts with daylight to break down organic dirt.
The second stage is “hydrophilic“. Here, instead of forming droplets, rainwater hits the glass and spreads evenly, running off in a “sheet” and taking the loosened dirt with it, also drying quickly without leaving streaks.
It is important to consider self cleaning glass as lower maintenance glass rather than maintenance free glass!
Will self cleaning glass work in a balustrade?
Self-cleaning glass is particularly well suited for in skylight windows or conservatories, or for the sides of highrise buildings. The coating needs enough exposure to direct sunlight in order to break down dirt. When installed vertically in a balustrade, the glass doesn’t get as much exposure, making its self cleaning properties less effective. The minimum recommended angle is 10° from horizontal so that rainwater can flush away loosened deposits.
As the ‘self-cleaning’ element of the glass is a coating, it is not advised to be used in areas where there will be traffic. The coating has the potential to scratch and scuff very easily. Once the coating has been scratched/scuffed, it always shows up on the glass. Even the usage of glass suckers when installing would leave visible marks! One glass processor advises wearing cotton gloves when installing the glass to protect the coating.
So whilst self cleaning glass installed in an external balustrade, that is exposed to both sunshine and rainfall, will potentially keep itself “less dirty”, in many balustrade applications the full benefits of self cleaning glass won’t be realised as the panel doesn’t get enough direct sunlight or rainfall to work as intended. Of course, self-cleaning glass used internally will offer very little, if any, benefit. It is also important to take into account that most “off the shelf” self cleaning glass is only coated on one face, so as both sides of balustrade glass are exposed to the elements you will still need to clean one face.
Self Cleaning Coatings
In many instances, applying a ClearShield coating by Ritec, or a similar alternative will be far more beneficial on balustrade glass panels. See our article on this preferred “less cleaning” balustrade glass solution here.
Advantages & disadvantages of self cleaning glass.
There are several pros to using self-cleaning glass, particularly if you dislike the idea of spending a lot of time keeping your glass looking perfect.
There are some things that it will not self-clean, like paint or builders dust etc. To remove brick, cement or plaster dust for example will probably need persistence with a water hosepipe. That said, it does what it says on the tin and does overtime self clean off the vast majority of organic dirt.
The UV rays in the sun reacts with the dirt to break it down and then relies on the rain to wash the dirt off. In areas where there is little rain, this might not be a good choice of glass.
However, as the ‘self cleaning’ is a coating on the outside, it does have the potential to scratch and scuff easily. Once the outer layer has been scratched/scuffed, it always shows up on the glass.
Self-cleaning glass will prove ineffective if installed under an overhang or in a position where daylight and/or rain cannot reach it, as it has been designed for exterior use only.