By Stuart McGinlay, structural waterproofing specialist at Wise Basement Systems
WINTER has firmly descended on Scotland, and professionals in construction should expect and prepare for an increase in rainfall, and snow, to come with it. Edinburgh was lashed with ‘thundersnow’ early in December, while severe weather caused delays on rail and roads across the Highlands last month, with the Met Office warning that homes and businesses could be flooded, causing damage to buildings.
January is traditionally the month with the most rainfall in Scotland. With rain expected on 18 days of the month, it’s important property owners, as well as construction teams, know how to prepare for and deal with mass rainfall and even floods. In Scotland, floods can strike quickly and without warning, which means damage is costly and difficult to repair. Preparing as much as possible can mitigate against lasting damage and means repairs can be completed quickly and safely.
Resistance vs resilience
For properties in at-risk zones, it is important to assess protection measures before floods occur. These actions fall into two categories: flood resistant or flood resilient measures. Resilience measures look to mitigate and reduce the damage caused by flooding in a property, while resistance measures seek to prevent water ingress by creating watertight barriers. This means floodwater is unable to enter a building because waterproof membranes have been used.
General design philosophy
Once resistance and resilience measures have been taken into account, there’s a common methodology for ensuring no water ingress in a building. This is a combined approach that involves two barrier methods. First, floodwater is excluded from the building using various barrier methods, which are applied to the structure and to points of entry such as doors and service penetrations. These barrier measures, if breached or damaged during a flood event will be backed up by internal waterproofing methods, which should in any substructure (cellars or basements) comply to BS8102 2009. In retrofit scenarios a waterproofing system is often now adopted, these are known as drained protection measures involving hidden cavity drainage membranes, drainage channels, floor gullies and a pump. This means penetrating floodwater will be controlled and diverted behind the membranes and finishes, before being pumped out of the building at a faster rate than it can enter the premises.
In case of overtopping, protracted periods of ingress, or bypassing of prevention measures such as leaving a door open inadvertently, the internal finishes are designed to be resistant and “recoverable” quickly.
This will protect vulnerable parts of a property – particularly those at lower-ground or below ground levels, where water is most likely to get in and cause lasting damage.
What to do in the event of flood damage
If a property succumbs to flood damage, it can create dangerous situations from an electrical, structural and hygiene point of view. Before clean-up, you should reach out to trained experts to evaluate the affected property and identify all the damage and structural hazards. This allows the clean-up and rebuilding process to take place as efficiently and safely as possible. It’s also worth consulting a qualified electrician, as they can check all the electrics in the building are safe, and establish what equipment can safely be used during the clean-up process.
Property experts can help to assess damage to the structure and recommend a course of action for restoring a property to its pre-flood state, while they will also have access to specialist equipment like a pump and generator. Having a clear plan can help to reduce the stress of dealing with the aftermath and ensure restoration takes place before water damage causes timber decay.
Flood damage can not only be costly and difficult to repair, but it can also be incredibly dangerous and distressing. It’s important to prepare a property as best you can to reduce damage should a flood occur. Flooding and damp proofing give a property the best chance of restoring it to its original state in the most timely and safe manner possible.