Keeping timber surfaces outside can be challenging. The Irish weather is against us. The accepted wisdom is to protect it using a more or less transparent oil or resin.
Does it work well? Not really, the oil becomes the problem.
Overcoating increases the opacity of the stain to a point where the veins are no longer seen. There is flaking too, followed by a weary sanding job.
There is an alternative consisting in keeping the agents responsible for the damage away.
This is done by using an appropriate biocidal detergent.
Wood rot is caused by a fungi. The biocide should be used to saturation point so as to kill the nescent fungal hypae before damage is done. The black dots are the tell- tale sign, if kept away, the wood will not rot.
Treated this way, natural timber will change appearance under the influence of the weather.
Wood is made of 3 main constituents.
The cellulose represents approximately half the mass. It is organised as short sharp needles woven in long strands. The needles have a binder to form a sophisticated composite material with good mechanical properties.
The lignin, a hard polymer resin accounting for a quarter of the wood mass.
The remaining mass is a mix of hemicellulose, minerals and an array of polymers providing natural defences, colour, smell etc.
When exposed, sawn timber will first lose the water soluble elements exposed to the rain.
The other polymers, including the lignin, will become water soluble under the action of the light. This phase is observed by a change of colour known as photo oxidation.
The combined action of light and rain will gradually expose the silver grey cellulose.
As the saw cut through the needle longitudinal arrangements at every wave in the grain, the unbound needle ends tend to rise under surface desiccation feeling sharp and abrasive to the finger.
Such a textured surface retains moistures and becomes a natural host for an array of biological species: Bacteria, fungi, and algae. They feed on the substrate and release metabolites preparing it for further faster feeding.
The bio-colonisation of bare cellulose is easy to control.
A product such as Algoclear Pro ticks all the boxes with regard to environmental footprint, safety, and ease of use. It is applied with ordinary garden implements.
The periodicity of application will vary from site to site. Twice a year is a good starting point.
If a shady corner requires a more frequent application, just reach out for the watering can for a localised treatment.
Done in time, no brushing is necessary.
Does it treat other surfaces ? Yes, very much so: The biocidal detergent acts on the biofilm, regardless of the nature of the substrate.
The Algoclear Pro treatments are particularly effective on porous surfaces.
