There is a staggering variety of external wall systems available to self builders. It seems like every supplier has their own version, or set of versions, of the external wall system. Some provide a single-skin system that is a combination of the timber-frame skeleton, the insulation infill and the technical sheathing on both sides of the closed panel. Others provide a double-skin system and even a triple-skin system to maximise the heat and sound insulation qualities.
There is also a varied selection of external cladding, offering a complete range of thicknesses of each of the three skins, where all 3 skins are provided. The quality of timber is variable, depending not only on the type of tree but where it was grown. There are different qualities of plasterboard, weatherproof board and breathable membrane. Insulation can be specified by type and quality and the inclusion of a services cavity is optional.
Certification of materials and systems is organised by a variety of technical bodies. Each supplier quotes the certification they have achieved and these include ISO9001,