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News / Specials
May 21, 2015
May 11, 2015
While internal timber surfaces are able to be readily & satisfactorily coated with a wide variety of paints, stains & oils, the performance of exterior finishes, particularly on timber surfaces exposed to the elements of UV light, heat, cold, water, dust & grit, is an entirely different matter.
External dark coloured timber projects that are subjected to full sun exposure during Queensland's hot summer months can lead to shrinkage & distortion issues. This can occur to either naturally dark timber (oiled or clear finished) or dark coloured stained or painted timber.
If you are painting timber cladding, fences, decks or furniture that are fully exposed to outdoor weather conditions go lighter instead of darker. Dark coloured surfaces in hot sun exposure can reach temperatures of exceeding 70 Degrees Celsius. This will result in the timber 'cooking' & drying out to under 8% moisture content. Shrinkage & shrinkage distortion can result, and even correctly seasoned timber, may end up with unacceptable appearances.
Darker colours absorbing more solar radiation than light colours will also deteriorate the finish of the timber rapidly. Light colours, particularly white, reflect the maximum amount of UV light possible & provide the best protection to both the timber & paint film.
Fig: Distortion in dark coloured timber exposed to full sun
These types of performance issues can be minimised by following Timber Queensland's recommendations, including the use of appropriate robust fixings, & light or pale coloured stains or paints
Resource: Timber Queensland
Finishes For Exterior Timber 
Finishing Timber Externally
Outdoor Timber Performance
May 6, 2015
Whilst recently performing a six month inspection, a client of ours noticed the knots in his timber were leaching out. To assist in determining the ultimate cause of this situation, 5 Star Timbers worked with a Timber Queensland Technical Consultant & one of Taubmans paint experts to solve the case & assist in finding a solution.
All timber species contain naturally occurring extractives of one type or another. These include resins, gum & tannins. It is not uncommon for some of these extractives to 'bleed' through paint finishes, particularly where initial moisture levels in the timber may be high, where high temperatures mobilise the extractives & / or where timber has not been 'sealed' with a quality oil-based primer.
'Knotty' softwoods including hoop, cypress & other pinus species can have high levels of resins associated with the knots, particularly knots that are dark coloured.
Fig. An example of knot bleed in LVL
To minimise the potential for resin bleed from knots, Timber Queensland's technical information recommends knots be sealed with a two pack polyurethane prior to application of an oil based primer. Sealing knots with a silver frost paint or shellac has also been found to have some benefits, although not as effective as polyurethane.
Where knot bleed has occurred such as above, scrape off any excess resin, clean with white spirits, lightly sand, apply a knot sealer, prime spots with an oil based primer & apply top coats. There is, however, no guarantee it may not reappear.
Source: Timber Queensland Technical Update - April 2015
Timber Queensland Finishes For Exterior Timber
Timber Queensland Treated Pine Cladding
Taubmans D682 Prep Right Traditional Undercoat
Treated LVL External Guidelines
Check out the Technical Data Sheets available on the 5 Star Timbers website
or give us a call on 07 3386 0595 or 07 3386 1055 & we'll happily help you out.