Zinc Oxide is known to have mildew retarding properties and is especially useful in humid or wet climates. It is generally recommended to add 20% Zinc Oxide when using Allbäck's linseed oil paint outdoors. Add 200 mL of Zinc Oxide Additive to every litre of paint and for all coats. This is a good general rule for most projects but ultimately depends on project conditions.

To be effective, it is recommended to have at least 10% Zinc Oxide, but adding too much Zinc can potentially lighten the colour. When adding Zinc Oxide to your paint, start by adding 10% and work up from there.

Allbäck Zinc Oxide as additive gives full control to the painter over how much to add to the paint to meet the unique demands of each project. For example, in arid climates or in most indoor environments, little to no Zinc Oxide may be necessary. Alternatively, in climates that are especially favourable to microbe growth, more Zinc Oxide, even up to 35%, can increase resistance but may lighten the colour of the paint.

Zinc Oxide can also have a mild siccative effect, meaning that the paint can dry (oxidize) a little faster and become a little harder. This can be useful when painting floors or surfaces that are exposed to a lot of wear.

Notes on preventing mould & mildew

Mould and mildew can occur on all kinds of surfaces where the conditions for growth are favourable. When planning a strategy to avoid the occurence of microbes on a building surface, we must think about how to maximize the impact of our efforts. Zinc oxide and other paint chemistry is one component, but we must also consider other variables that can have an even greater impact:

• The Environment: Is the relative humidity high? Are surfaces exposed to the sun? Is there good air flow around the building? Are there trees, shrubs, and other vegetation? Are there pollens or other foods for microbes on the surface?
• The Construction: Do the elements of the building shed water adequately? Are there gutters and downspouts installed? Are horizontal surfaces such as window sills sloped away from the building? Are cracks, holes, and joints sealed?
• Paint Chemistry: Is the surface well cleaned? Is there zinc oxide in the paint? Is there an adequate paint film to seal the surface?

Notes on cost

Adding Zinc Oxide to the linseed oil paint does not increase its overall cost per area. For example, adding 20% zinc to the paint gives you 20% more paint and also covers 20% more surface.