Castan symbol


“Castan” (Welsh) - Chestnut

Protected by a spiny outer casing called a burr, chestnuts are said to encourage longevity, abundance and help with the grounding and centring of energy.


The Castan tree house incorporates a highly insulated core with ancillary spaces around the perimeter. These spaces, intended to be used for relaxation, are clad in narrow lengths of local Welsh timber, which resembles the burr or outer layer of a chestnut. The timber screen offers privacy and protection from the elements, creating a space of tranquillity.


It is designed to sit amongst the trees whilst remaining versatile and contemporary. The Castan is ideal as an additional space on your land, for diversification or for paying guests on a glamping or camping site.


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Product Details

“Helygen” (Welsh) - Willow

Nature is the leading inspiration for the Helygen®.

Natural materials, such as larch cladding, are utilised alongside modern materials to produce a design that balances concerns for the immediate and wider environment with the need for functional usage and aesthetic elegance.

The willow tree was the inspiration for the external cladding. As the tree ages the bark of the willow splits, producing an abstract lattice. The way in which light from the sun interacts with the swaying branches of the tree has also influenced the design. The sun casts beautiful shadows and alternative perspectives are created through which the beauty of nature can be appreciated. 

Helygen® is a responsive and intelligent structure, designed with functionality and versatility in mind so it blends easily within the environment. It sits comfortably in different settings, such as green pastures and woodlands and more built-up environments such as private gardens, towns and villages. It offers individuals, couples and groups privacy and comfort from where to contemplate and experience nature. 

The tiny house movement, an architectural and social movement started in the USA, which advocates living simply in small spaces and promotes eco-friendly choices has also been a strong influence in the design of Helygen®. Furthermore, Japanese architecture, traditionally typified by wooden structures raised off the ground and in particular Japanese micro-architecture, have heavily been a source of inspiration.




Larch cladding net



4.8 by 4.8 metre core

Diameter = 8.6 metres
Prices: POA

20m2 insulated core

High specification windows and doors

Electric underfloor heating

Fitted kitchen including sink & hob

Fitted shower room with shower, free standing basin and toilet

Optional: Hot Tub & Deck


5.4 by 5.4 metre core

Diameter = 9.4 metres
Prices: POA

26m2 insulated core

High specification windows and doors

Electric underfloor heating

Fitted kitchen including sink & hob

Fitted shower room with shower, free standing basin and toilet

Optional: Hot Tub & Deck


6 by 6 metre core

Diameter = 10.3 metres
Prices: POA

32m2 insulated core

High specification windows and doors

Electric underfloor heating

Fitted kitchen including sink & hob

Fitted shower room with shower, free standing basin and toilet

Optional: Hot Tub & Deck


Natural light floods the kitchen thanks to floor to ceiling windows and a translucent ceiling.
Unlike many other pods on the market, our kitchen is not housed within the living space. Our hand crafted kitchen has the added benefit of being equipped with a double hob, ample storage and space for a fridge-freezer and oven. Radiant heating can be installed to effectively heat the space whilst in use.

Shower room

Perform your ablutions in style. A luxurious shower experience awaits.
The shower room also benefits from floor to ceiling windows and a translucent ceiling. The space can be effectively heated by the addition of a radiant heat source.

A wet room shower drains through a deck that seamlessly blends with the rest of the room.

The pedestal basin is located to allow optimum use of natural light.


The central insulated core of the Helygen, which provides the main living and sleeping space, is constructed with structural insulated panels (SIPs). Structures built utilising SIPs typically have excellent insulation standards and lower running costs, compared to structures utilising alternative materials.

Depending on the size and configuration of the model chosen, the core is able to comfortably accommodate between two and four people. Thermostatic underfloor heating is standard but its use is minimal due to the air tightness and insulative properties of the SIPs.

Boot room

The shower room and living/bedroom are accessed via the boot room. Dirty boots, muddy clothing and wet activity wear can be removed without having to soil the living space. Ample storage exists for spare bedding, suitcases and visiting pets.


On a wet day, views can be enjoyed from the veranda. To increase comfort and versatility of the Helygen, glazed sliding doors can be commissioned to enclose the veranda from the elements. The veranda can provide access to an open decked area that can be designed to suit the nature of the site. The decking can be used for barbecues and stargazing, with easy access via the veranda to the kitchen. The open-air decking area is for the whole family, with sufficient space to house an array of patio furniture and flora. 

Structurally Insulated Panels (SIPS):

The SIPS panels are used to create a core which is highly insulated, providing a comfortable thermal environment in all weather. Manufactured locally to our studio, we ensure minimal transport emissions and work closely with the manufacturer to provide quality assurance.

Welsh Larch:

All of our larch cladding boards are from the local area and cut to size at a local saw mill.


The steel is sourced locally, and the manufacture of the base takes places close to our manufacturing site. This allows us to minimise emissions due to transport whilst working closely with the steel fabricator to provide quality assurance.

Birch ply:

We source all of our plywood from FSC certified manufacturers from Europe. Birch is native to Europe and is a renewable source of timber. Birch ply offers excellent strength and durability with minimal defects.


Marmoleum has a very low carbon footprint. It is composed of 97% natural materials and uses 43% recycled materials. Its natural bactericidal properties prevent micro-organisms such as Salmonella, MRSA and C Difficle from multiplying.


We source our EPDM for our roof coverings from the UK. EPDM has a low GWP (global warming potential) and can be reused and recycled into many different products. It has a life span of between 25-50 years and doesn't pollute rainwater so is an ideal material for rainwater harvesting.

Windows & doors:

All the windows and doors are made up of glass, wood and aluminium. The wood is FSC certified. The windows and doors have a lifespan of at least 40 years, with a 12-year product warranty from the manufacturer.


The Castan requires minimal heating due to its highly insulated core. Electric underfloor heating is included as standard in the core of all models but will only require minimal use due to the highly insulated core. The periphery spaces have the option of radiant heating, a highly efficient method of heating and will be provided by a local manufacturer.

Connection will be required to sewer or septic tank, cold water supply and single phase electricity supply. Alternatively for off-grid version with compost toilet, photovoltaic panels will need to be located remotely. A battery bank can be accommodated in the design.

Click the links below to download our product information

Design Inspiration

Models & Prices



Site requirements