Free draining balconies are either drained through without any form of water management, or are free draining using soffits or drip trays to the front edge, the side of the balcony, or to a spout rather than to a RWP (Rainwater pipe).
A free draining balcony is often assumed to be a drained through open balcony, which has no soffits. Free drainage balconies usually collect and transfer water to the front of the balcony. The exception of this is using perforated or timber soffits etc which are really a decorative solution only.
Both NHBC and other warranty providers schemes expect there to be some form of rain water management and therefore controlled drainage solutions using soffits which do this through free draining the water consistently across the front edge of the balcony are typically required. This is usually adequate even when balconies are over 6sqm.
Previously, we found some clients choose to clad the underside of the balcony with decking to match the top surface. This would normally be in a free draining situation where water falls between the deck boards. This has become less common recently, as it doesn’t give the longevity of properly coated aluminium soffits and is often not a cost benefit despite having a lower perceived value. Unfortunately there has been a significant number of balcony fires in the UK during 2018. A number have spread rapidly because of there being either no soffits or combustible soffits. Read more about the effects of balcony fires in our whitepaper.
We created the video below of a NHBC scheme where the smaller balconies are free draining to the front and those over 6 square metres are pipe drained to RWP’s. You can see a clear comparison of how balconies drain using different forms of soffits on the balconies, and the difference is very little.
Sapphire highly recommend the use of aluminium soffits to draing the water to the front edge and also to help prohibit the effects of balcony fires spreading from one floor the next.