Conventional paints and varnishes are made from ingredients synthesised from petro-chemicals, a process which requires large amounts of energy and therefore produces significant greenhouse gas emissions. In addition this process also generates lots of waste, most of which is the result of synthesis and is therefore not easily re-absorbed back into the eco-system and in some cases can be highly toxic. Most conventional paints and varnishes contain things called volatile organic compounds or VOC's which are basically the solvents used to carry the colouring (pigment) in the paint. As the paint dries the VOC's evaporate producing that 'newly painted' smell. This process is also know as Off-gassing and is both damaging to the environment (depleting Ozone) and potentially to your health, as many have been classified as toxic and carcinogenic. These VOC's are also responsible the headaches, throat & eye irritations and feeling of sickness that can result from painting without adequate ventilation. Oil based paints have the highest level of VOC's and interestingly most water-based paints actually use even more complex chemical processes in their manufacture and many still contain VOC's.

The pigments themselves also often contains heavy metals such as Lead, Chromium and Cadmium all of which can cause significant damage to the eco-system when they are released into the water system.

Environmentally friendly paints & varnishes, in contrast try to use natural ingredients including pigments, and as a result any waste that is generated is able to be harmlessly re-absorbed into the eco-system. Much simpler production processes also minimise energy consumption and associated greenhouse gas emissions. Eco paints & varnishes also try to avoid the use of all VOC's (some still have very small trace residues but at very safe levels) and are therefore, from a DIY perspective, much healthier to work with. Some eco paints are entirely solvent free and others use lower levels of more eco-friendly solvents such as citrus oils and solvents called Aliphatic hydrocarbons. Whilst these solvents are VOC free it should be noted that they are derived from crude oil so do contribute to global warming.

Other things to consider:

Point of manufacture - paints made and imported from abroad will necessarily mean higher embedded carbon emissions from additional transport miles. A number of eco-friendly paints are manufactured in the U.K. It should also be noted that in most cases a number of the raw materials will also generate transport related emissions as they will need to be sourced abroad. Again most environmentally friendly paint manufacturers look to reduce these 'costs' and publish details on sourcing data.

As well as the energy used in the manufacturing process, in some cases there are very high amounts of energy required for the extraction of raw materials (embedded energy). Ti02 (titanium dioxide), a very widely used white pigment which also improves the 'coverage' qualities of paint is a very good example. Because it is derived from titanium extracted by deep mining it has one of the highest 'embedded energy' values of the raw materials used in paint. Ti02 also contributes to atmospheric acidification and waste into water discharge due to the TiO2 process. Some manufacturers are now sourcing and using alternatives which can significantly reduce the overall embedded energy cost of their products.

Paint stripers & brush cleaners also use solvents, in many cases more powerful and potentially harmful to both human health and the environment than the one's used in paints. The good news is that eco-friendly alternatives are also now available.

Limewashes: Limewash is a traditional breathable coating made by mixing Lime Putty with water (the recipe varies but is based on an equal parts mix). Lime putty is made by adding Quick Lime (made by burning limestone or chalk in a kiln) to water - a process known as slaking. The resulting Limewash can be mixed with a range of natural pigments to create coloured finishes and can be used externally or internally on lime plaster, lime render, stone or brick. Unlike modern sealants where the material is porous limewash is naturally absorbed into the surface and absorbs carbon dioxide from the atmosphere (replacing that which was expelled when the limestone or chalk was burnt to create Quick Lime) and hardens to form calcite crystals.

Limewash is particularly recommended for traditional buildings where the materials need to breath, but it can also be used on modern build.