I'm still dithering about whether to buy one of the recycled plastic houses (like the Solway Ecohouse) or whether to build (OH to build) my own. If the latter then we'll use Eco Sheet which is a recycled plastic "chipboard". it's 18mm thick and pretty rigid. Although the edges look open, the holes don't penetrate into the board so no frost damage. Sqaure sections are available for making corners - they aren't necessary but make it look nicer. OK, it only comes in a flecked grey - no pretty colours and is £36 + Vat for an 8' x4' sheet. 12mm marine ply is £26.75 a sheet - didn't get a price for thicker stuff as the enquiry was to do with our building project which only needed 12mm. You can get Eco sheet from Wynnstay if you have one near you, or from one of their distributors - I went to www.heritageandsons.co.uk just off the M6 near Coventry to look at the hen house and the various boards (Paul Heritage was really helpful - and it was Sunday morning!), or you can look here www.solwayrecycling.co.uk/agricultural/ecosheet. Although it is expensive it is so easy to clean - can be steam cleaned or washed down, and it means far less nooks and crannies for redmite etc. Even with marine ply you still have the problem of expose edges which can delaminate. If we do the selfbuild on the hen house in addition to our own I'll try and post some pictures - but don't hold your breath!