We recommend a coat of natural paint only for wooden windows. The often heard statement that pigments do protect wood from sunlight is basically correct. However, what is not being mentioned is that wood by itself finds the best and most suitable colour. If the painted colour is too light it doesn't protect from the sun. If it is too dark, the wood absorbs too much heat.
1. The sun's weathering impact:
Ultraviolet (UV) light generally causes just a light deterioration of wood. This breaking down process however is very slow and it takes centuries for deep traces to show up. It is not necessary to protect the wood surfaces of a well-built wood dwelling with a coat of paint against the sun.
The life expectancy of a wooden dwelling has little to do with paint and paint brush - and traditionally, wooden buildings never saw a coat of paint. Most people nowadays don't hesitate and apply a coating to seal any wooden surface thinking they are preserving the wood. However, just a few years later, they are faced with paint peeling off and wood rot underneath.
It would be strange to think that after all those years working as a carpenter his hands should have remained with the same skin colour as our youthful hands.
Why then, do we expect the skin of our wooden buildings to always look young and new? Why do we demand that a building needs to be the same yellow or brown colour from every angle at all times?
As children, we often sat next to our granddad and our delicate hands would touch the protruding veins on his old hands. It was a fun game to squeeze his hands for a moment and watch how his blood streamed back into the veins and filled them up again.
Can you imagine, if all humans had the same skin and hair colour? Luckily, this isn't the case. We also ask our children to have respect for our white haired elders. The wrinkles and grooves in old people's faces are wonderful and honest witnesses to their trials and triumphs.
Buy only paints and products where the manufacturer lists all ingredients used. A quality wood coating is meant to allow the wood to breathe and not seal its pores. In this way, you can enjoy your wood product not only visually, but also its ambience and moisture-balancing properties.
If you want to fully enjoy living with wood, it is important to only use natural paint products or leave it completely untreated.
Natural paints derived from paint-derived oils, resins, natural waxes and minerals consist of substances which appear in nature.
It is best for the decking to lie on wedges which are narrower than the boards themselves. The verandah should have a slight slope, for the water to run off.
For outdoor constructions, avoid building exact horizontal areas and use some simple practices in combination with the right selection of wood.
It is also better to divide the deck area into segments and then place them on the structural elements without screws. The same principle works for balconies and all other similar constructions.
Sleepers should be chamfered so that moisture can run off.
Whereas a deck built with alpine Spruce that was harvested at the right time and installed constructively, lasts for 30 years or longer. The same decking made with sapwood free oak is more expensive but will last 50 years or longer!
Infested roof trusses and wooden houses can be treated with hot air by specialized companies for the same effect. A re-infestation in older wood is practically impossible.
If we choose appropriately, harvest at the right time, season wood properly and use constructive building methods, chemical treatments become redundant.
Risk of infestation by Longhorn Beetles in context to the age of the wood:
The table shows that the older the Timber/Wood, the less likely it will be attacked by the Longhorn Beetle.
Should the Longhorn Beetle have established itself, there is still no need to panic!
The Longhorn Beetle is the most significant of all the damaging insects. If we use reasonable caution and constructive measures when building with wood, it does not pose a real danger to our buildings.
For an external cladding, the vertical facade is preferable to horizontal. Water can run off all the wooden components which are exposed to rain and dampness and doesn't pool.
Weather boards are to be installed onto a slatted frame allowing free air movement and circulation to wooden building components.
A wide enough roof overhang prevents direct contact with rain and is more effective than treatments. Old, wooden buildings always have a wide roof overhang to protect external walls and cladding.
1. Protect the building materials and construction from rain and moisture. Avoid lengthy exposure to the weather and finish the roof quickly.
(Use well-seasoned Timber / Wood)
It would be worth writing a whole book specifically about proper construction methods. Here are some worthwhile recommendations which should be followed by you, the architect, biological building officer and trades people.
The conclusion is, no fungus can grow under 20% moisture content. If we dry wood properly, there is no need to use chemicals to protect it from fungi and insects.
The two things which we need to adhere to are:
Furthermore, it is very rare that even wood with 20-25% wood moisture content is infested by destructive fungi.
(The proper storage and drying of wood is an important step to prevent it from rot and decay.)
Indoors, wood in a heated room ends up containing around 6-10% moisture. Basically any wood in the building industry (apart from balconies and terraces) which is protected by a roof is just not moist enough for fungi to exist and grow.
When further processed, no matter whether it turns into a piece of furniture, floor, walls or roof, the wood dries out even more.
The moisture content of external wall cladding is around 12-18% (depending on the atmospheric conditions).
When boards, squared timber or slabs are being stacked, covered and stored outside for air drying, the wood ends up with a moisture content of approximately 12-20% (depending on the climatic conditions).
Like all living organisms, fungi too look for the best possible conditions and prefer to take the way of least resistance. These optimum living conditions however are not around 20% but rather around 30% moisture content.
Natural wood preservation to prevent fungi
In this table, you can see the ideal moisture content which fungi need to grow to decompose wood.
(Table: Bernhard Leisse: Treating Timber Naturally, Heidelberg 1994)
Holz100 Canada Inc.