Guest Blog: Andy McHugh, RAB Consultants (7th November 2016)
To coincide with the Environment Agency’s Flood Awareness Campaign, I felt it was appropriate to highlight the importance of having independent and professional property surveys undertaken when considering adopting Property Level Resilience (PLR).
PLR has over the last few years grown to be an affordable and effective first line of defence in mitigating against internal flooding of property. But when it comes to flood protection it is not just a case of buying products off the shelf – there is no one size fits all solution. I have seen the good and the great but unfortunately I have also seen the bad and the ugly!
Appropriate property surveys involve looking at the flood risk, the householder(s) and the property construction as a whole. Not just protecting by slapping on flood boards for doorways (which is too common). Appropriate surveys involve recording ground and threshold levels and reviewing flood risk data to determine how frequent flooding is expected, to what depth and from what source. Simple flood risk searches are available (e.g. Landmark) which tell you the flood risk area a property is within but these do not tell you the actual risk of internal property flooding.
The obvious and often overlooked flood risk reduction methods include keeping water away from a building fabric. Soft/hard landscaping, Sustainable Drainage Systems (SuDS), boundary wall defences, temporary barriers are likely to be the more effective PLR but they are often technically or financially impracticable for a single household. PLR compliments traditional flood defence schemes and can be considered for residual risk of flood defences breaching/overtopping and alternative sources of flooding.
If the floodwater is expected to be more than around 600mm deep, it is not recommended that you try to keep it out. This is because the water pressure could cause structural damage. In this case, it’s best to let it in but you can adapt the inside of your property, so the damage and impact is reduced. We must also remember that PLR is only as good as its weakest point! Other routes of water ingress exist including poor quality mortar, unsealed cable entry points, service meter boxes, airbricks, vents, waste water and foul water pipes. If these are unprotected, then a property is likely to flood despite householder investment in other mitigation measures.
We must also manage expectations. There is always residual risk – flood boards may overtop or not be deployed in time/fitted properly. Furthermore, most property surveys only look at above ground routes of water ingress. There is a risk that water comes up through the floors of properties – this highlights the importance of using pumps as a means of managing water levels at the property.
Improving the skill sets of those involved in making properties more resilient is one major step forward in ensuring consistent standards amongst property surveyors and ensuring customer confidence in PLR. The Property Care Association’s ‘Property Flood Resilience for Surveyors’ training course seeks to address this need and is a highly appropriate course for property surveyors.