Not only is C16 treated timber cost effective to buy, it has many uses such as roof rafters, timber framing, ceiling joists and floor joists. It can also be used as decking joists and for garden buildings.
C24 timber has been graded to a higher standard than C16. It’s a premium timber that can handle higher loads and wider spans. C24 boards have a more uniformed and neater appearance as there are fewer physical imperfections.