The very latest manufacturing methods are now being used by many independent ‘smaller’ conservatory companies, meaning that they are now able to deliver some truly amazing designs in wood without the expense that you may have associated with that type of extension.
Although many wooden conservatories are constructed from hardwoods such as oak, but a good alternative is Idigbo, a West African hardwood that is sustainable and easy to work with and is used quite frequently with no problems in many situations.
Another alternative to hardwood is to use engineered wood, which is a composite made of waste wood or offcuts which, for want of a better description, are ground up together and then bonded with adhesives. The result is 2 types of engineered wood called oriented strand board (OSB) and laminated strand lumber (LSL) with OSB being a type of board or panel and LSL is similar to structural timbers (‘two x fours’ etc.)
Whichever you decide, all woods use in modern construction would be ‘sustainable’ and so whether you opt for a hardwood or an engineered wood conservatory you will still be environmentally friendly.