Balustrades (or parapets) on decks can serve several functions, ranging from simple decorative boundaries to full safety barriers. Even a small change of level can be a hazard, particularly for elderly or infirm users. Unless the deck surface is flush with the surrounding ground level, a parapet or edge protection detail should be incorporated.

For very low-level structures, this may take the form of a simple decorative rail, a trellis panel, a raised planter box, a bench or seat, etc. The height of the parapet depends on how far the deck surface is off the ground: For 'high-level' decks over 1000mm high - parapet height should be 1000mm Where parapets act as safety barriers, they should be designed and constructed to meet the A.S building regulations