Waterproofing: A Life or death decision
In 2015, at a party in Berkeley California, a balcony collapsed killing six people and injuring seven others. That there were thirteen people standing on the balcony shouldn’t have been a problem; that was well within design tolerances. So why did the balcony give way?
In June 2017 the California Contractors State Licensing Board released documents which shed light on the reason for the collapse. Quite simply, the materials used in construction were not those specified in the original design. Given that the area was known to face regular bouts of inclement weather the original specification included a requirement for a protective cover to be used during construction and the balcony supports to be pressure treated.
Neither of these preventative measures were carried out. In addition, rather than using plywood as specified in the design, the contractors installed oriented strand board; a product which is not only known to be water absorbent, but also to crumble when exposed to moisture over a period of time. The result of these construction failings was that six students lost their lives.
The report is a strong reminder for all those of us in the building, construction and roofing trades about the importance of selecting and using the right materials for the right job. There is no point in designing a supposedly waterproof balcony if the materials used are going to decay under the impact of water. Even when we look to install a green roof which is designed to absorb and slowly release moisture, the substructure has to be waterproof if the building and its inhabitants are to be protected.
And it doesn’t matter where we live in the world, there is no one size fits all solution to waterproofing, whether it be for flat roofs or balconies, walkways or other structures. Every project has to be reviewed to design the optimum protection for the anticipated use. In Cornwall that means choosing products which not only have good solar protection but can also withstand the heavy rain storms which sweep in from the sea on an increasingly regular basis. Even here, different products would be chosen for different projects. So we work with builders and architects to identify which product is most appropriate taking into account considerations such as the nature of the building, its orientation, anticipated footfall and so on.
With care and careful consideration of all the appropriate factors, structural waterproofing can provide a safe and secure environment. It’s only when corners are cut or inappropriate products used that waterproofing failures at best lead to leaks, at worst to a potentially life-threatening situation.
