Working with water – amphibious houses

In recent years the UK has suffered from a plethora of severe flood events, in areas such as Cumbria, Yorkshire and Somerset¹.

Unprecedented rainfall and river levels have led to widespread flooding, resulting in large-scale disruption to communities, loss of basic services and long and costly recovery processes¹.

The recently published National Flood Resilience Review highlighted that with more frequent and severe flooding events likely in the future, action must be taken to improve our protection from and resilience to flooding^1,2. As part of this on-going change of thinking, innovative and more sustainable ways of construction, which work with water rather than against it, are being explored^2,3,4,5.

A possible solution is the concept of amphibious houses². Initially trialled in Maasbommel, The Netherlands as part of an award winning development of 32 amphibious homes and 14 floating homes, they are built in a way that allows them to rise up with the flood waters^1,5,6,7. The technology used was shown to be effective in a flood in 2011 in which the houses successfully floated with no problems detected⁷.

A flood prone island on the River Thames near Marlow, Buckinghamshire became the site of the UK’s first amphibious house in 2014^5,6. The house sits on fixed grounded foundations, until a flooding event occurs and the building is able to rise up with the flood waters ^5,6,8. This works based on Archimedes’ principle that the volume and mass of the house are less than the equitant of water, creating buoyancy⁵. The house itself is a timber frame construction built upon a buoyant waterproof concrete platform within a wet dock, the base of which is permeable allowing water to enter and leave freely^5,6,8. As floodwaters rise the dock fills with water allowing the house to become buoyant^5,6,8. The movement of the house is guided by four steel posts which keep it in place and allow it to rise by up to 2.5m, which is in excess of predicted future flood levels for the area^5,6,7.  The services are fed through flexible pipes allowing the house to remain fully functional during a flood event^3,6.

The use of amphibious construction systems could open up development opportunities. The pressing demand for new housing in Britain has led to a situation where houses are being built in high-risk flood zones at almost double the rate as outside of flood plains⁶. Under the National Planning Policy Framework (NPPF) 2012, developments should be planned in order to withstand the increasing threats of climate change⁹. Additionally, inappropriate developments in high risk flooding areas should be avoided, however where it is deemed necessary, measures should be put in place to mitigate the risk without increasing the risk elsewhere⁹.  Amphibious housing developments could meet the criteria set out in the NPPF by providing an appropriate, sustainable and responsible solution to building in flood prone areas^2,3,9.   This could offer new opportunities to utilise land for development, which would have been unsuitable using traditional construction techniques^2,3,4.

A perceived limiting factor to an expansion in the numbers of amphibious houses is the higher construction costs, with the addition of amphibious systems to the first UK based house estimated to have raised expenditure by approximately 20%^3,6. However, standardisation and larger scale adoption of this construction practice would be likely to significantly reduce costs^3,6,10 . This suggests that on a larger scale development it is possible they could become a financially viable construction option in the future^3,6,10.

References

1. HM Government. (2015). National flood resilience review. Retrieved from https://www.gov.uk/government/publications/national-flood-resilience-review
2. Strangfeld, P., & Stopp, H. (2014). Floating houses: an adaption strategy for flood preparedness in times of global change. In Proverbs & C. A. Brebbia. (Eds.), Flood recovery, innovation and response IV (pp. 277-286). Southampton: WIT press.
3. Spowart, N. (2015). How floating Dutch homes simply rise with the floodwater. Retrieved from: http://www.thenational.scot/world/how-floating-dutch-homes-simply-rise-with-the-floodwater.11797
4. The European climate adaptation platform. (2015). Amphibious housing in Maasbommel, the Netherlands. Retrieved from: http://climate-adapt.eea.europa.eu/metadata/case-studies/amphibious-housing-in-maasbommel-the-netherlands
5. (2014). UK’s “first amphibious house” can float on floodwater like a boat in a dock. Retrieved from: http://www.dezeen.com/2014/10/15/baca-architects-amphibious-house-floating-floodwater/
6. Wainwright, O. (2016). Like a shimmering sea creature’: Britain’s first amphibious homes. Retrieved from: https://www.theguardian.com/artanddesign/2016/feb/02/baca-architects-pioneers-of-amphibious-housebuilding-flood-defences
7. Amphibious homes, Maasbommel, The Netherlands. Retrieved from: http://www.urbangreenbluegrids.com/projects/amphibious-homes-maasbommel-the-netherlands/
8. Baca architects. (2014). Life with water – amphibious houses. Retrieved from: http://www.baca.uk.com/index.php/living-on-water/amphibious-house
9. Department for communities and local government (2012). National planning policy framework Retrieved from: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/6077/2116950.pdf
10. Royal institute of British architects. (2015). Formosa-the UK’s first amphibious house. Retrieved from:https://www.architecture.com/FindAnArchitect/ArchitectPractices/BACA/Projects/Formosa-TheUK39;sFirstAmphibiousHouse-132908.aspx