Flat Roof Deck Construction Details

This article discusses rooftop deck construction details to avoid building leaks or rooftop deck safety hazards.

Flat roof deck construction details.

Roof top deck construction. They are merely placed on top of another structure. Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading. A note to consider before construction.

Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. Proper drainage at the edge of the deck must be provided usually with gutters. Building a deck over a flat roof is very similar to building a deck over a concrete patio. These decks are often referred to as floating as they are not secured in place as a stand alone structure.

The roof deck should be properly flashed with a highly durable material that is compatible with the deck material copper lead epdm etc where it adjoins the house. Consider geography budget and use for the roof to determine the best option. If insulation is installed below the flat roof deck this is called a cold roof. The construction of the flat roof is similar to that of the timber upper floor.

Special attention must be paid to railing posts and any other penetrations of the roofing surface.