Thanks Zach. Thats a great help, thats exactly what Im intending on doing, an egg crate false bottom with a thin layer of aquarium foam on top then cover that with bark. I will have a water feature in there on an internal loop. The two wooden walls made of the spray foams stuff, coated with silicone and peat, cork logs and vines and some moss so a mix of bases for different varieties. Its a nice sunny day today and the lights have been on in the cabinet for a few hours and its reading 23 degrees I doubt even in a heatwave it would go much more. Once I have got the insides assembled I shall start monitoring the humidity. I shall hunt down a good LED to supplement the lighting. Im now putting together a list of the Orchids that I like that are available to me, then I will mark each one with its temp/humidity requirements so I can then work out which will be the most suitable.