just been looking round for a new shed to replace my smaller brick shed and the prices are stupid for the sizes ! as am remodeling the garden ive decided to build a shed and use the back wall of it as part of the fence. i was thinking of 25mm thick decking boards but ive no way of making the joints water tight. ive seen t&g joints sheds, only wood i can buy with the t&g is floor boared ? any ideas ??