I have a green-house which is seated on a concrete base. Between the greenhouse frame and the base I put some wooden supports approx 40x20 mm. The aluminium from overhangs the wooden support so there is no access to it once installed. The supports have just about rotted away totally - been there for quite a few years.
I want to reseat greenhouse - replace the wooden lats. What would be best preservative to apply to the wood - it will get very wet as rain runs down glass and sits around the base.