Greenroofs.com: The Eco-villa at Soneva Kiri, By Louis Thompson

The eco-villa is a prototype zero carbon emissions Six Senses hotel suite we just completed building at Soneva Kiri and Six Senses Spa on the island of Ko Kood, Thailand, as a forerunner to our forthcoming Zero emissions brand. It is essentially an experimental showcase of a range of environmental technologies incorporated into a bio-climatically designed luxury pool villa made from locally sourced building materials.

The structure has been erected by a team of Thai craftsmen, including mud brick experts, terracotta potters, master carpenters, and stonemasons. We have designed and built this structure to demonstrate that it is already possible to provide the same levels of service and comfort as a five-star luxury hotel room using modern building techniques and state of the art, zero carbon emissions, renewable energy technology combined with indigenous skills and knowledge, even in the remotest areas. The construction, landscaping and operation are based on permaculture design principals to ensure that waste is minimized or reused.

Structure

Low embodied energy materials, recycled waste products and green building techniques that require minimal mechanical energy were used as much as possible - no cement or concrete was used in the structure. The foundations are made from sandstone boulders extracted from the excavation of other villas on the site and post holes were chiseled by hand to receive the hardwood posts. Most of the timber used for the post and beam structure was harvested, kiln dried and treated on site ourselves and is held together with hardwood dowels handmade by a local boat maker. Some poles and rafters were made from locally sourced Casuarina driftwood. The remaining timber poles and beams are locally sourced, plantation eucalyptus and the roof decking is plantation rubber wood planks harvested from mature rubber plantations in a nearby province. Forestry stewardship council pine is used for the joists and reclaimed teak is used for the decked areas. The teak leaf ceiling gives the building a nest-like quality.

Subsoil from the site was mixed with rice husks and straw (agricultural waste products) and molded to make adobe mud bricks and plaster for the interior walls, site sourced sandstone was used for the exterior walls and the soil excavated from the pool was reused on the green roof. Recycled egg crates were used in the drainage layer of the green roof and soda water bottles were used as glass bricks for the shower.

Human health and biophillic themes were an important motivation - non-toxic adhesives and wood treatments have been used throughout the building (latex, boracare, lime mortar) and electro magnetic waves have been reduced as far as possible (no wireless technology) - the building is therefore entirely suited to guests suffering from allergies or sensitive to electro-magnetic fields.

The building's excellent insulating properties are provided by cellulose insulation in the roof made from recycled newspaper, heat stop glass and the thermal mass of the 1m thick walls. The green roof covering the structure is another layer of insulation which helps control storm water runoff and also provides a habitat for native flora and fauna as well as integrating the building with the surrounding landscape.

I used a layer De boer water proofing bituminous landscape membrane which has worked very well; this was followed by a layer of recycled HDPE egg trays that I used for drainage followed by Polyfelt TS 10 filter fleece. For the substrate I used 1 part subsoil from the natural swimming pool, 1 part locally sourced coconut fiber for water retention and 1 part burnt rice husks (a kind of biochar) and I added small amount of chicken manure. I then covered the whole 260 m2 roof with an erosion control mat made from palm husk fiber and planted into holes in this material (some days we have 40cm of rain in a 24 hour period so I didn’t want the roof washed out).

In the future I would really like to experiment with simulated terra preta mixes using biochar and hope to do a rooftop vegetable garden some time. Strangely enough there is very little research on green roof plants in the humid tropics – despite the fact that they help reduce AC load and could be very beneficial for storm water management in tropical cities.

At the beginning we experimented with food plants (I have a permaculture background) – rice grew quite well in the rainy season, then we harvested some beautiful sweet potatoes but I wasn’t getting the look I wanted so I experimented with some more architectural plants - I am not totally sure of the exact species of fern but it is part of the Nephrolepis family and grows in sandy soils on the island - it looks very like macho fern N. biseratta (bear in mind I did the project in a very remote location). I also experimented with philodendrons, Monstera deliciosa, and hoya flowers. Once the ferns took hold I just went with it and the roof was slowly colonized by other native species….I now have to cut down saplings before they become trees!

We also built a pottery kiln on site and produced our own terracotta pipes, up spouts and downspouts for rainwater collection. Copper rain chains were also made on site based on a design traditionally used in Japanese Buddhist temples.

The design of the kiln inspired the construction of a small wine cellar:

Technical Elements

Light is provided by a central skylight for daylight and viewing the stars at night. Super efficient lighting is provided by LED and CFL bulbs in environmentally friendly light fittings designed by Six Senses. A rainwater harvesting system linked into the resort's main rainwater collection will be installed. The water will pass through a membrane filtration system before being used in the bathroom.

The building is cooled using two experimental methods – firstly the use of a 24,000 btu solar air conditioning unit from Solcool that consumes only 1,200 w at peak load and secondly a passive cooling system incorporated into the thermal mass of the building. The fundamental idea is to cool the mass and maintain the temperature thanks to the insulating materials. A solar hot water panel provides hot water for the showers and washbasins.

The natural swimming pool acts as both a rainwater storage system, a wildlife magnet and a swimming pond – the water is circulated via a pump through reed beds filled with aquatic plants that will lower the nutrient content and filter the water. A UV (ultra violet) light in the pipe system will eliminate pathogens and a series of waterfalls aerate the water. No toxic chemicals are used; it is simply filtered rainwater.

All the buildings' energy will be produced via a hybrid system composed of a 1.7 kw Skystream wind turbine, 6.2 kw of photovoltaic solar panels and a micro-hydro system using waste water from the restaurant above. It will be stored in batteries for nighttime use and a 3-day backup. Guests and members of the local community will have access to this area to learn about sustainable power generation and storage.

A reed bed (constructed wetland) receives all waste water and septic tank effluent, and the treated water is reused for landscape irrigation to feed the bamboo privacy hedges with nutrient rich water and thereby provide food (bamboo shoots) and rapidly renewable construction timber.

We have preserved much of the existing vegetation on the site and the area was selected because a large rubber tree had fallen there and cleared many of the larger trees. The remaining landscaping is a combination of endemic, adapted and native plants for aesthetics and some organically grown edible plants (banana, papaya, herbs) and medicinal plants for guest consumption.

The project is aiming for LEED™ Gold or Platinum certification.

The zero carbon, bio-climatically designed luxury pool villa guest suite at Six Senses, Soneva Kiri Resort.

The eco-villa will essentially be an experience that will allow guests to tread very lightly on the earth for the length of their stay and we hope it will serve as a model to Six Senses and the rest of the industry. It is only a first step on our path to constructing zero carbon emission resorts.

Louis Thompson

Publisher's Note: The Soneva Kiri by Six Senses Spa Resort website says "Remote but accessible aptly describes the Thai island of Kood, on which Soneva Kiri is set amidst the lush tropical rainforest, off the south-east coast of the Gulf of Siam. International guests are personally met on arrival at Bangkok’s Suvarbuhmi airport and transferred to the resort’s own airplane for the one-hour flight to the Soneva Kiri airfield. From the air, the beauty of untouched Thailand and Koh Kood, with its white sandy beaches is immediately evident." Click above to learn about the resort and see beautiful photos.

Louis M. Thompson, LEED AP, holds a BA in French and European Studies and is the Permaculture Designer for Six Senses Resorts and Spas and the Soneva Kiri Senior Deputy Project Manager.

Louis says the objective of the Eco-villa at Soneva Kiri was to create an alternative model for the luxury hotel industry based on permaculture design principals, including low-impact energy efficient rooms built from natural materials and powered by renewable energy sources that combine aesthetic considerations with ecological design elements such as organic vegetable gardens watered with naturally filtered recycled water, and sustainable waste management systems that transform waste into a valuable resource.

Contact Louis Thompson at:

Soneva Kiri Resort
19F Two Pacific Place
142 Sukhumvit Rd.
Bangkok 10110, Thailand
Portable (+66) 8955 11542
e-mail: louis@sixsenses.com

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