Rising water levels are an increasingly prominent concern for the construction industry. Populations are growing, but coasts are creeping in, and clearing inland land isn’t always an option, considering habitat loss and existing structures. Water-based communities — which float on the surface of seas and rivers — are a promising solution.

Constructing on top of the water instead of retreating from it lets cities expand without fighting for available inland space or worrying about rising tides. However, it’s not an easy process. Building envelopes will need to adapt to support these towns of the future.


The Unique Challenges of Water-Based Construction

The most obvious challenge exteriors face in a water-based community is a higher threat of moisture. Water damage claims already cost insurers $13 billion annually, and 32% of U.S. homeowners have experienced damage from weather within the past five years. Being so close to a larger volume of water — and the storms that come with it — raises those risks.

A floating structure also makes it harder to ensure stability and safety. Buildings in water must be able to move as sea levels rise, but too much movement can put unwanted strain on both the exterior and interior. Ensuring all the electronics and thermal management systems inside work despite movement and moisture can be challenging, too.


Keys to Building Envelopes in Water-Based Communities

Given these obstacles, building enclosures in floating developments must focus on a few key characteristics. Here’s a look at the most important considerations.

Buoyancy

Traditional water-based communities build on stilts, but buoyant foundations and exteriors are a better long-term solution. The Waterbuurt neighborhood in Amsterdam is a prime example, as its houses adapt to changing waters by floating instead of remaining still.

Of course, floating buildings can’t be totally free — otherwise, they’d run into each other. Waterbuurt gets around this by anchoring to submerged concrete platforms and steel pylons. There’s enough slack for them to move vertically with rising tides, but the anchors prevent horizontal movement.

Moisture Resistance

Keeping water out is another big concern. Building enclosures must use moisture-resistant materials, as they’ll encounter far more wetness than a conventional structure. Aluminum siding is a potential option because aluminum does not rust and is impervious to mold and mildew, so droplets won’t create further complications.

Extensive weatherstripping around doors and windows is also necessary. Double doors and multi-pane windows provide additional protection should any moisture get through the first layer of weatherstripping.

Weather Resistance

Similarly, water-based communities must consider extreme weather outside of water-related hazards. Because temperatures fluctuate far more over land than they do over water, coastal areas often experience stronger and more persistent winds. Worsening climate change may push such conditions to extremes with storms like hurricanes and monsoons.

Strong bolts around doors and windows can minimize damage from high winds, as do additional frame reinforcements. Materials like aluminum and galvanized steel are also ideal, as they provide greater strength-to-weight ratios, maintaining durability without compromising buoyancy.

Drainage

Building envelopes in these developments also need efficient drainage to manage any water that seeps through. Trench drains along the exterior of a structure — especially near doors — are the most basic solution and will divert water before it enters.

The enclosure itself should feature some drainage, too. Often, this means installing an additional layer of cladding behind the first layer but before the insulation. This material should be corrosion-resistant and slope to direct water to floor drains. Another water-resistant wall on the interior completes the seal.


Water-Based Construction Poses Possibilities and Challenges

Water-based communities are a unique solution to several of urban expansion’s current problems. They provide a handy way to erect new buildings without rising sea levels or limited inland space imposing limits. At the same time, construction in such areas must follow strict guidelines.

Attention to factors like buoyancy and weather resistance will help developers build water-based neighborhoods safely and efficiently. When that happens, the world can house a growing population while managing the effects of climate change.