For the cladding on the outside of our house, we really wanted a beautiful plywood. It also had to be suitable for external uses, and act structurally as a shear wall. We started looking at a variety of beautifully grained hardwoods, from FSC certified Australian plantation timbers, in stable 18-25mm thick sheets.
By the time we checked our budget we were left with 12mm FSC certified but reputedly dodgy Indonesian Melapi, or 12mm B grade Radiata. The melapi is on the left, and was our final choice, primarily because the board is also structural, and because the veneer is a hardwood
The choice of coating has been tough. I checked a number of reviews, spoke to coatng suppliers, builders and painters. After a short time it became clear that no matter what we coating the boards in, the following things were constant:
1. We would be re-coating in 2-5 years.
2. We could only slow the process of greying in the timber if we applied a colour tone to the coating.
3. If we didn't apply the coating to the manufacturers recommendations, we were likely to be struck by plague, pestilence and pain to our private parts. This last one I didn't mind, but I don't fancy a pestilence on my property.
In the end we chose Deck-Doc over Organoil and Cutek Low-VOC. I was impressed with the lanolin covering from the Deck-Doc, and unimpressed with the sales-rep from Organoil who wouldn't warrant the product externally in shady areas where the cladding stood a chance of growing mould in winter months.
On the right you can see my heroic attempts to coats the internal sides on the plywood sheets prior to be fixed into place
And I am happy. The Deck-Doc goes on smoothly, and I only need a single coat. It dowsn't smeel very toxic. Excess oil rubs off easily, and based on a hose test, we seem to be getting some good water resistance. Time will tell. Unfortunately. Since it's a 2-storey building, it's a huge mistake to make if I have got it wrong.
In the image on the right you can see the sheets beginning to go up in place.