Flat Roof Flashing Height

What typical detailing methods are used to seal flat roof penetrations.

Flat roof flashing height.

This height has become the industry standard and is recognized by most membrane manufacturers. Bs 6229 2003 flat roofs with continuously supported coverings code of practice and bs 8217 2005 reinforced bitumen membranes for roofing code of practice both state that if unwanted water ingress into the building is to be avoided all weatherproofing upstands occurring around the roof area. The standing seams are laid flat 8 from the vertical wall folded 3 4 and secured with copper cleats spaced 12 o c. This dimension should be measured from the finished surface of the roof which would.

The flat roofing material must go up the wall a minimum of 12 or up the wall and over the top of the wall if the wall is less than 12 high. Typical methods include banding pitch pockets and cover flashings. Typically 10 by 8 inch 253 mm x 203 mm flashing is chosen. For example 3 tab shingles usually have a 5 5 8 inch 143 mm exposure.

Vertical flashings must be a minimum of 8 inches above the completed roof surface. Copper locking strips of the same weight as the flashing are soldered to the pans between seams at least 6 from the wall and engage the base flashing in a 3 4 lock. Which would include abutments rooflights and service vents etc must have a minimum height of 150mm. Banding is typically used to seal soil vent pipes on single ply roofs such as fdt rhepanol pib and involves wrapping an unreinforced membrane around the pipe to a minimum height of 150mm.

The 8 inch height prevents water from pouring over the top of the flashings into the building or system.