Factors Affecting Performance
The performance of paints and stains is a significant factor affecting the service life of a building.
Fashion, new technology, aesthetic improvements and changes in function often result in modifications to a building and maintenance of its external envelope is also necessary from time to time.
In addition to these changes, the durability of paints and stains on timber or timber products is influenced by a range of physical factors including those listed in Table 1.
Table 1: Factors effecting performance of paints and stains
|
Factors |
Effect on Performance |
|
Substrate |
Refer Table 2 (under Substrates) |
|
Environmental Conditions |
Dry temperate conditions give better performance than damp, humid conditions. Marine and industrial environments can provide relatively severe exposure conditions. |
|
Pre-treatment |
All wood is impregnated with preservative before painting or staining. When combined with primers, putties, sealants and the correct installation of flashings and top coats, good long term performance/durability can be expected. |
|
Maintenance Schedule |
Re-coating before major paint film breakdown occurs, will improve durability at reduced cost. In new construction (for all substrate types) expect maintenance to be required on certain sections within a few years. Generally after that early maintenance has been undertaken you can expect long term performance of the paints and stains. |
|
Application Procedure |
Paint and stains are best applied by brush or roller for the first coat. The shear forces created by the brush against the substrate improve the wetting out of the film, moving the paint or stain deeper into the substrate. Always follow the recommended number of coats and pay attention to the coverage rate noted on the can as that controls the final dry film deposit. |
|
Building Design |
Protection from elements using roof overhangs, verandas, pergolas, etc. and avoiding water traps/pooling, will promote improved performance. |
|
System choice |
Surface coatings (paints and stains) are available in many options. Choose premium products designed for your chosen wood type. Follow the instructions carefully and don’t mix the brands. Paint manufacturers have developed paint or stain systems as a result of research. Don’t drop a coat, follow the recommendations closely and pay attention to coverage rates applicable to your chosen substrate ie. rough sawn timber uses a lot more stain. Work out how much you will need before you start, using the same batch if possible. If in doubt, check with the manufacturer or do a coverage/colour test before you start. |