to be honest youd be better off gettin to know the laggers on sites around the country, the stuff they use is not the best for flooring but it sure does the job when it comes to panneling the sides and the interior. nuclear sites, petrochem refineries, normal power stations, all these have laggers, theres sure to e some private firms too which, in the same way as steel suppliers have skip loads of offcuts, have skip loads of ally, i managed to get 4 strips of 1.2mm x 3m x 1m and a sheet of 1.2 3m x 1.2m for free by just askin about what they had for scrap, its a long shot, but may well be worth it
