Timber Preservative and Reactive Diluent Agent. This contains a preservative to help deter rot, and it reduces both the viscosity and the surface tension of the mix so that it will penetrate further into the timber. The secret to preventng rot is to properly seal the timber up so that it doesn't get wet and this product in conjunction with BoteCote does this better than any competing system. Our application note 'Timber Saturation' has more details and test results. Make up a normal 2:1 BoteCote mix and add up to 20% of TPRDA to it and use the mix for the first coat on the timber for optimum results.