If your home or property has peeling paint on woodwork, concrete, steel etc you will know all too well the frustration of having your home repainted only to see that paint blistering and peeling off again in a few short months.
This problem can have many causes and is usually not that easy to solve after it occurs.
What are the causes of paint peeling? Sometimes paint blisters and peels or flakes of due to inadequate cleaning or surface preparation prior to application of the paint. Perhaps the incorrect primer is used, maybe no primer is used. Paint applied to previously poorly prepared surfaces is virtually certain to become loose and come away from the substrate / peel off.
Some of the most common substrates that ‘throw paint off’ in buildings are as follows: concrete window sills, wall cappings, precast concrete panels, wooden window frames, fascia boards, gates, galvanised steel gates and railings, shop fronts, painted brickwork, to mention a few. Shiny surfaces like aluminium, uPVC, glass etc are also well known problems for peeling paint.
Let’s take paint peeling off concrete first. Window sills and wall cappings are two of the biggest offenders for this problem. One of the reasons that happens is because those precast concrete sections are usually produced in moulds and those moulds are normally sprayed with a mould releasing oil to make removal of the concrete from the moulds easier after it sets etc. When those concrete sections are installed, most people are unaware that there is oil contaminating the pores of the concrete and continue to apply paint.
Avoiding or curing the problem. New precast concrete should be thoroughly cleaned with a solvent to get rid of the oil and allowed to dry prior to application of the primer coat. When surface is dry, an appropriate primer should be applied to ensure adhesion to the concrete. The latest developments in this area are known as stir-in bonding primers such as E-B or Bonzit etc which you add into the first coat of any water based paint thereby saving an extra application. If concrete has been painted already and has a history of peeling, you should remove all traces of loose material with a wire brush or even a power washer used at a very sharp ‘scraping’ angle.
In the case of wood such as fascia boards etc, the peeling problem occurs usually due to inadequate priming in the first instance or adequate time was not allowed on newly planned wood prior to painting. As with concrete above, you should remove all traces of blistering or peeling paint by sanding or chemical remover if appropriate. When wood has been prepared, apply a good quality primer or if you have a good paint stockist nearby you might be able to obtain one of those stir in oil bonding primers which can save you additional time and work.
If you need to paint shiny surfaces like glass, tiles, melamine, plastics etc you need to take great care and select a primer or an easy surface prep specially developed to provide a grip on such surfaces.