Should treated timber vary in colour from one piece to another?

Freshly treated timber will have variations in colour. This is due to the relative proportions of heartwood and sapwood in a pack. Sapwood is more permeable and so takes up more preservative. This results in an initial variation of colour from green (sapwood) to beige (heartwood). Once built and exposed to the elements, the initial strength of colour fades to a warm, honey brown and in the long term will become a natural silver/grey.

Timber is a natural product and variations in character should be expected. Occasionally timber containing high or mobile resin levels can give a blue colouration at the time of treatment. This will fade to rapidly into the overall natural green/beige colour.