I am about to start boarding out the garden room with dry lining board. In a couple if places the runs are greater than the 2 400mm and so I will have to form end on joints. The question is how to finish these joints using a dry lining approach. Side to side joins are easy because of the thinning of the board edges but when jointing end on no such provision is obvious so any tape will be quite proud and I am worried the joint will be visible. Any suggestions? Can you get boards with thinned edges all round?