architecture design sustainability

Five ways to build a flood proof home

With floods washing up in several parts of Britain this winter, there is a lot of discussion about how to prevent and manage floods. It’s all very political, with accusations of government bodies not doing enough or flood defences being inadequate. As usual, climate change is carefully avoided as part of the official silence on the matter. For today though, I just wanted to highlight five different ways to make a house flood proof.

Most of these techniques are well established. Some of them have been used for millennia by riverine or coastal communities. As the weather becomes more extreme, more houses will be at risk of flooding and these techniques will become more important.

1. Elevation
This is the oldest and most obvious way to build a flood proof house. If you must build near a river or the sea, just make sure you lift your building above the likely height of the flood waters. There are a number of ways to do that. You can build a house on stilts, a traditional form in many places. You can build it on a raised platform like a beach house, or on a bank of earth or concrete. Larger office buildings might put a sacrificial car park underneath. A treehouse could also fall into this category. Here’s a an elevated house from Thailand and one from New Orleans:

elevated-houses

2. Floodwalls
Rather than raise your home above the waters, a second common technique is to protect your home or property from the water by building a sturdy and waterproof wall. This can be done to protect whole towns and villages, but there’s no reason why it can’t be done on individual dwellings. Perimeter walls with watertight gates are one approach. You can also incorporate berms and walls into the landscaping, keeping the water out of a whole property or allowing the garden to flood while protecting the house. That’s what engineer Carl Canty did, below left, so his garden can be under three feet of water and his house is still dry. The example on the right is less subtle, but still effective.

personal-flood-walls

3. Dry floodproofing
If you’re going to let the flood waters reach the walls of your house itself, you might want to make them watertight. This can be done with sealant, or building in a waterproof membrane. Doors and windows will need to be flood proof. Airbricks and utilities entry points can be raised or sealed. Essentially, dry waterproofing is all about keeping the water out of the building. Germany’s Hafencity, which I wrote about recently, uses this approach for properties on the waterfront. Those are some Hafencity storm doors on the right below, and a house in Grand Rapids demonstrating the principle on the left.

dry-waterproofing

4. Wet floodproofing
Rather than keeping the water out of a building, an alternative approach is to let it in but minimise the damage it can do: fit a solid floor rather than wood, move power outlets up the wall and ensure that any unmovable furniture is made of a material that can safely take a soaking. Wet floodproofing is often used to retrofit flood-prone properties that the owners can’t sell, which is making the best of a bad situation. Houses built for it are much better, such as the house on the left below which is built to withstand a tsunami, or this waterfront hospital in Boston. Planned with climate change in mind, its lower floor has a swimming pool and non-essential services so that the whole thing can flood without interrupting patient care.

wet-floodproofing

5. Floating homes
Second-guessing how far future floodwaters might rise is a dangerous game in an age of climate change. If your house can float, it’s guaranteed to always be above the water. One way to do it is to build on pontoons and have a building that’s always floating. Below is an ice-bound floating development in the Netherlands, which has many examples of waterborne architecture. Amphibious houses are slightly different. They’re on land and only float when there’s a flood. Britain’s first was recently completed, and here’s one in Thailand. These are more experimental, but we may well see more of them in future.

floating-homes

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35 comments

  1. I have heard about a lot of different things that can be done to help flood-proof your home so that all of your belongings stay safe when the water comes. I think that one of the best options would be to build your house on a platform so that the water can’t reach the top. I think that people that already have their houses built should get in contact with house raising service and companies to get their already made houses raised.

    1. Hey,Thanksgiving for this matter explanation about floods,
      I have a science fair project on this and this is the elevation matter for my project….once again thanking you 🖤

  2. Thanks for the article. We’ve been quite concerned with all the flooding that’s been happening just this year alone, so we’re definitely considering better alternatives to waterproofing our home. There’s a building construction panel that’s being released into the market this next year that prides itself in being waterproof. It’s called the PermaPanel. We’re considering building our home out of it, especially because it’s a lot more economical than SIPs and traditional framing– with fewer contractors needed.

  3. House raising seems to be the time-honored method to protect your house. By having the house at a higher elevation, you can protect it from most dangers with water. My wife and I are thinking about moving to a flood-prone area and want to protect our house if we do.

  4. Hi JEREMY WILLIAMS ,
    This was a excellent informative post you have shared on this page about the architects of building but the methods of construction and constantly evolving knowledge about the fire performance of buildings means that fire regulation needs to be regularly updated. The lack of a periodic timetable for updating of the Building Regulations Approved Documents, which has allowed review of Approved Document B to be almost indefinitely delayed, is highly problematic.
    Thanks.

  5. That is true, we have to prepare our house from the floods. This article suggests several ways to avoid our house and the furniture being damage from the floods. I agree about floating homes, because in the future floods will comes more frequent because the climate changes. Thanks for sharing this information.

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  13. flooding is one of the major concern in building a house. Good thing i found your article so I can have an idea of these things. I’d like to know more about floating homes, I hope you can have an article mainly focused on that topic

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