Large Size Heavy Duty Double Pergola Complete DIY Kit, Quality Tanalised Timber.Tanalised, pressure treated heavy duty timber Double Rail Pergola DIY Kit, manufactured from high quality redwood timber treated to ensure a 10 year warranty for rot. This version is our range of larger sized pergolas with double rail configuration which adds further timbers giving a more substantial look and feel. We have a great selection of pergola's and gazebo's, see the full Timber Pergola and Gazebo Range, if you are after a more cost effective