At the end of August the news was full of images of inundated streets, as Houston took the full force of Hurricane Harvey, and India, Bangladesh and Nepal struggled with devastating floods. For a couple of weeks the most read post on the blog was this one from last year: Five ways to make a flood proof home. A lot of people were searching for information on how to protect their homes and property.
With that in mind, today’s building of the week is the Resilient Home constructed by BRE in Watford. Opened in February this year, it’s a normal Victorian terrace house that has been refitted to demonstrate how to make a home flood resistant.
When a home is flooded, it will usually need to be re-floored, re-plastered, and re-wired. Furniture and appliances will need to be replaced. Unfortunately, many repairs will use exactly the same techniques as before. If the house floods a second time, it will be wrecked all over again. Residents in Carlisle experienced this recently, after two floods in a decade. This can bankrupt people and leave homes unsaleable. It’s important that homes on floods plains are refitted to resist water damage. There’s a growing urgency to this kind of flood resilience as climate change puts more homes in harm’s way.
As my previous post explained, there are several ways to make homes that don’t get flooded. It’s best considered at the design stage, and it’s harder to add in afterwards. If you’re retrofitting a house, then flood resistance and resilience is a more likely solution than flood proofing. Resistance means that the house has been sealed up so that water will be slower to get in, but it won’t keep it out forever. (Like my ‘water resistant’ rucksack – it can shake off a shower of rain, but don’t drop it in the lake.) Resilience means that when if a larger flood does overcome the resistance measures, damage will be minimal. The water will drain out quickly, and walls, floors and electrics will be okay.
To make their demonstration home, BRE gutted a house in the same way that builders would have to do after a flood. They then refitted it with a series of flood resistance measures:
- First, there’s a sump with an automatic pump so that water can drain to a low point and be pumped out of the house. Wall and floor membranes direct water to the edge of the room, where drain channels under the skirting boards allow water out and down to the underfloor sump.
- Doors and windows are flood resistant.
- Wall insulation is water resistant, and waterproof plasterboard is fitted horizontally.
- A normal chipboard kitchen is a bad idea in a home that might flood. This one is made from resin boards, and units are raised up on legs, with kickboards underneath.
- Wooden floors and carpets will be wrecked by flooding. They have been replaced with tiles and rugs.
- The sewage pipes were fitted with one-way valves so that water cannot come up from underneath.
- Sockets have been raised, and wiring has been done from the ceiling down. The TV is wall-mounted, and the fridge sits on a concrete plinth.
It’s a more expensive way to repair a home after a flood, but you only have to do these repairs once. If the alternative is repeated expense and disruption, it’s a price worth paying. You can find all the details here. This graphic from This is Money also shows some of the measures that can be incorporated into flood repair.