Penetration depth is difficult to estimate as it is dependent on many factors. The most important factors are the viscosity of the epoxy combined with the porosity, and the grain structure of the wood. While RotFix and S-1 are ultra-low viscosity materials, wood is not consistent. Because of these factors even among like species of wood, you can get extreme differences in penetration depth.
When using wood consolidators like RotFix Penetrating Epoxy or S-1 Sealer, we have found that the best results are achieved by removing as much soft/rotted wood as possible, then applying enough product/coats to achieve a film of epoxy on the surface.
Please refer to our EndRot Application Guide for detailed instructions.