How to protect your biggest Investment
Exteriors
Cleaning Your House
Like washing your car, cleaning your house will help it maintain its good looks for much longer. Airborne contaminants, including salt deposits, which settle on your paint film, can attack the surface and cause premature breakdown. Annual washing of your home will help maintain the fresh appearance of your paintwork.
Use specialist Exterior cleaners available from DIY stores or paint stores.
Be mindful if using bleach based cleaners as they can affect colour and also subsequent paints if bleach isnt removed fully. This is an effective way of removing moss mould and algae which will grow through the paint film reducing its life but must be flushed.
Avoid letting run off from cleaning go into the stormwater and subsequently into our waterways.
Fading
Like all exterior surface coatings, the colour of your paint finish may be affected by U.V. light. Most Premium paint suppliers use high quality concentrated tinters, and they have improved considerably over the years but even these are liable to change after constant exposure to sunlight. Any changes will be gradual, but after a few years the difference between shaded and exposed areas may become noticeable.
Dark colours are obviously more susceptible to this, NZ sun is pretty harsh so
something to consider when choosing exterior colours.
Chalking
‘Chalking’ refers to the formation of a white, chalky powder on the surface of the paint film, which often occurs as the paint weathers and the binder is slowly degraded by sunshine and moisture, releasing the binder’s hold on the pigment. Over time nearly all paints will show some chalking when they are subject to outdoor exposure. Old paint is likely to be chalky.
Paints are essentially a combination of pigments – colour particles held together by the paint resin as the paint dries a thin layer of clear resin is left on the surface and the colour pigments are locked in below this layer. After years of sun and moisture degradation, this thin resin layer simply wears or erodes away – exposing the pigments below and as they are no longer bound into the paint film by the resin they are easily wiped off and this is what is referred to as chalking. This slow erosion is much more preferable than cracking or flaking and, provided the surface is sound and cleaned, once the chalk is removed it is ideal for painting over.
Chalking is more common where lower sheen or flatter paints are used. I always recommend semigloss as a minimum for exterior use. If the surface is badly chalked, it may be time to consider a clean and repaint.
Even if you extend the life of your paint, Cracking and ultimately flaking of paint can occur for a variety of reasons. Often these failures are due to the fact that the paint has inadequate adhesion and flexibility especially on moving parts such as window jambs.
When timber is involved, moisture intrusion results in swelling of the wood surface followed by contraction as the wood dries. The expansion and contraction cycles, often aggravated by freeze-thaw cycles, moisture, followed by heat can result in cracking and subsequent paint failure by flaking and peeling.
Cracking and flaking can also result when paint is applied too thinly due to overspreading (higher-than-recommended spread rate) or excessive thinning. These practices tend to diminish the paint’s final film thickness, so that it is more vulnerable to cracking and flaking.
Inadequate surface preparation can also cause these failures, especially when paint is applied to bare wood or a very porous surface without first applying a primer. A primer will provide better adhesion and will seal the surface, allowing the next coat (the paint) to perform properly.
As a rough guide a good paint job should last 10 to 15 years without failing.
Interiors
Cleaning Interior Painted Surfaces
Like the exterior intermittent cleaning of mainly horizontal surfaces to remove dirt, grime and grease will lengthen the life of your paint.
Spot cleaning of marks should be attempted with just water to start with and microfibre cloths, only resorting to harsher cleaners if necessary and always tested in an inconspicuous place first to test. Some paints are better than others for their wipeability.
Preventing Water from pooling on horizontal surfaces (this includes bathroom ceilings) is crucial for paint longevity. This can be achieved through good ventilation through mechanical means or simply opening windows in bathrooms and bedrooms. Excessive water should be wiped away. Water will soften your paint film if left and eventually fail.
MOISTURE IS YOUR PAINTS MORTAL ENEMY
Blocking
Thermoplastic paints (most waterborne paints fall into this category), particularly those with a high gloss, will soften under heat. Even a surface that may appear fully cured will soften and may stick to itself or other thermoplastic materials placed upon it, such as vinyl covered folders. The plasticiser in vinyl is prone to migration into touching surfaces.
Where possible, avoid storing vinyl covered objects on or against painted surfaces.
Hot window sills are not great places for knick knacks.
Surfactant leaching
Waterborne interior products in particular are vulnerable to surfactant leaching, where some areas of the paint surface appear to be covered in white streaks, giving a watermark effect. Surfactant leaching only affects the appearance of the paint finish, not its durability. It cannot be accurately predicted or prevented, but tends to occur when moisture settles on a film, such as in a steamy room like a bathroom, when there is moisture in the air on a cold and wet day or in humid conditions. Colours with higher levels of tinter are most prone to surfactant leaching.
Surfactant leaching is caused by water sitting on freshly applied waterborne paints. Water softens the fresh paint and draws out water soluble surfactants. As water dries off these are deposited on the surface. These deposits are easily removed early on by simply cleaning the surface following the interior paintwork instructions. The problem may occur once or twice again before all leachable material is completely removed. If left, the deposits may etch the surface and leave a permanent mark. This should diminish over a few months and is only of cosmetic concern.
