Chosing colours for exterior paints

For the past month I have been unexpectedly involved in the matching of colours in our production plant. The amount of orders received for colours that are essentially unsuitable for exterior coatings has been alarming. Several of these colours have been selected and specified by architects, making the chance of advising the client against proceeding very small. Always check with your supplier that the colour you have chosen is both u.v. and alkali resistant if it will be applied to an exterior substrate. Very often a colour very similar to an unsuitable option is able to be produced using resistant pigments. These pigments are mostly far cheaper than the problematic options, giving you added benefit.

Do it right the first time

I saw another example of poor options leading to time and money being wasted at a housing development this week. Exterior plaster was very poorly bound resulting in the addition of primers or surface densifiers being added to a very price sensitive coating budget. On questioning the site manager, we were told that there was no time or personnel available to re-wet the plaster once applied to the brickwork. This resulted in a very poorly cured substrate for painting. Even very gentle abrasion of the uncoated plaster resulted in removal of the very dry and powdery mixture. To rectify this prior to coating, bonding liquids, densifiers and primers were being tested to render the substrate suitable for painting. This apparently, the developer had personnel and time to do.
Had the plaster been re-wet two or three times, at 24hr intervals, after applied, it would have cured to the point that none of the above products would be required. Water would surely have been the cheaper option!!!