It depends on the potential fall height, how the deck is used and the local requirements. A small change in level does not automatically mean a balustrade is needed, but fall protection becomes increasingly important as the deck height increases. Check the requirements that apply to your property.
What lies below the edge and whether children use the deck also matter. On a multi-level deck, assess each exposed edge. Even at ground level, a balustrade can define the seating area and provide shelter or privacy. Where there is a fall risk, specify an appropriate height and design, with fixings into the supporting structure rather than decking boards alone.
