11 ESPLANADE

Cabin Area (GIFA): 82m²

GF & 1st Floor Area (GIFA): 107m²

1st Floor Balcony area: 12 m²

Procurement: Self-managed with Main Contractor

LABC: Cornwall Council (Plan Check and Inspections)

11 Esplanade is a sensitive remodelling and extension of a four-storey Victorian townhouse in Fowey, Cornwall. This project transforms the lower two floors and replaces an outdated garden cabin with a sustainable, maritime-inspired extension. Featuring a curved sedum roof, copper fascias, and silvered timber cladding, the new structure blends into the coastal landscape while enhancing estuary views and biodiversity.

Built using a glulam post-and-beam frame with reclaimed sheep wool insulation, the extension achieves Passive House-level airtightness and includes MVHR, underfloor heating, and high-performance glazing. Despite complex site logistics and planning constraints, the project was delivered for £390,000 and includes 92m² of biodiverse green roofing and a landscaped garden with 17+ plant species. The result is a low-maintenance, energy-efficient home that respects its heritage while embracing contemporary coastal living – an exemplar of sustainable architecture in Cornwall.

The Quoins (pictured above) is an end terrace 4 floor Victorian property on the Esplanade in Fowey. The project concerns the remodelling of the lower two floors, (Great Quoin) and Garden extension (The Cabin) into an amazing, timeless apartment complemented by a stunning redesign of the garden.

The new extension should be thermally efficient, maximising views and privacy whilst providing a naturally flowing living environment. The external aspects of the existing building from Esplanade level will reflect its Victorian origins.

The existing upper floor of great Quoin accommodates an entrance hall, dining area and kitchen/living room leading onto a balcony with spectacular river and sea views over the roof of the Royal Fowey Yacht Club. The existing lower floor contained two bedrooms, one en-suite and a further bathroom. The lower lounge connects to The Cabin, which contains a kitchenette, small dining area, lounge two single bedrooms and a shower room. The Cabin has no architectural merit and sits uncomfortably on a site that deserves a replacement building of high quality.

Taking its inspiration from the sails of yachts seen in Fowey Harbour just a few yards away and celebrating the town’s maritime heritage, the proposed replacement building features a flat but segmented curved roof covered in living plants of sedum offering a greatly improved outlook from the neighbouring properties whilst preserving their views of the Estuary. The fascia’s are clad in copper to minimise maintenance and once they begin to green will blend with the living roof minimising visual impact.  Timber cladding will weather to a muted silver grey, and conceal the new cabin when viewed from the harbour.  Generous roof overhangs shadow the glazing further reducing the buildings visual impact and provide solar shading.

The existing Victorian building has been sensitively re-modelled and refurbished retaining the charm and character of the original building whilst seamlessly flowing from old to new with a maritime feel.  A sweeping glass and steel first floor balcony compliments the sail-like green roofs and the minimal intervention approach respects the existing heritage but with a modern twist.

Due to site constraints (retaining wall & SWW main) and difficult access the construction method was carefully considered ensuring that beams and windows would be able to be delivered on a lorry into the centre of Fowey and also through a temporary path between the neighbouring chapel conversion.  The replacement building is constructed using a glulam timber post and beam frame with breathable fabric consisting of I-joist walls, roof and floors insulated with reclaimed sheep wool (see multi-coloured wool pictured above which is a by-product from a rug making industry) and high specification double glazed windows.  The post and beam frame also enables minimal excavation and reduced concrete via small pad foundations.  The majority of excavated material needed to be maintained on site due to access constraints and budget.  The landscaped gardens were therefore designed with this in mind.

Although the new building is connected to the Victorian property without thermal separation the decision was made to make the extension as airtight as possible incorporating a services zone internally which also provided the airtight layer; this helps to minimise heat loss and draughts.  The external sheathing board was also taped to further reduce air infiltration. Building Regulations did not require an Air Pressure Test; however we have detailed the airtightness to Passive House levels.

As the timber frame construction extended through the winter and the site being located in an exposed coastal location a tented structure was chosen to maintain efficiency, quality and keep the framework dry, which proved to be a huge success.

The basic principles employed during the design, specification and construction is to ensure that the building has low embodied CO₂ content.   The majority of materials  were selected that have not required a large amount of energy in their sourcing, processing or transportation.  The solutions include:

1. Reclaimed sheep wool: a by-product of wool based industries in our region. The material is waste and previously discarded. It is untreated and has no embodied energy in terms of processing and only limited transportation requirements all being sourced from within the region. The material also has benefits in terms of its hygroscopic properties enabling it to act in harmony with changes in atmosphere, humidity and the seasons in general. With regard to handling, the material is safe with no off-gassing present in proprietary insulation materials. Additionally there are no damaging fibres and therefore no irritation is experienced by site personnel.
2. I-Joists: Engineered timber joists made from small sections of timber and timber by products (see below). They offer many design and performance advantages over conventional structural products including a composition which resists shrinking and warping, an excellent strength to weight ratio straight and uniform dimensions. The joists also have FSC & PEFC Accreditation & Labelling, Life Cycle Assessment and ISO14001:2004 Environment Management System.
3. Timber: recognised as one of the most sustainable building materials, all timber has been specified carefully ensuring that the chain of custody is clear.  This protects against irresponsible sourcing and irreversible damage to delicate ecosystems. Where possible, we advocate the use of European timber (FSC & PEFC).  The cladding was specified as Iroko to minimise maintenance and increase longevity.
4. Timber by-products: such as the bitumen impregnated fibreboard to the roof (Bitroc), orientated strand board (OSB (air tightness layer)) have also been incorporated in order to utilise further waste products.  Additionally, these products have lower chemical content in terms of adhesives and binders than composite materials such as chipboard and medium density fibreboard, both of which have reported harmful binders which can cause a health hazard when working with the materials.
5. External Joinery: High specification double glazed windows were specified to help reduce heat loss.  Marine grade coated aluminium were chosen for robustness and future recyclability.
6. Wood treatments: have been selected which limits the amount of chemicals utilised within the building.  OSMO polyx hardwax-oil rapid for clear internal applications was selected because it incorporates natural wood wax oils which are solvent free.
7. Wall membranes: have been eliminated from construction. This serves to provide a breathing shell (vapour permeable) which is not susceptible to condensation build up and significantly reduces the risk of associated respiratory illness.  As it breathes the structural frame is less prone to decay and offers greater longevity
8. Green roof: consist of varieties of succulent called “sedum”.  These are extremely tolerant of dry conditions, have limited growth but also replenish themselves readily year-on-year.  This provides minimum maintenance and promotes a range of wildlife as well as looking spectacular year-round but especially in late spring during the main flowering season. This roof also assists the drainage of the building by slowing down/holding up the run off of water from the roof prior to entering a drainage system.
9. Green roof membrane: Due to the interesting roof forms and upstands GRP was chosen to provide a modern, robust and seamless roof.  The skills adopted are also inherited from the boat building industry which is perfect within a maritime environment.
10. Rainwater goods: Lindab Aluzinc coated steel rainwater goods were selected because of quality, durability, minimal maintenance, recyclability and it has the lowest CO₂ footprint of any other system.
11. Bitroc: naturally emulsified bitumen impregnated fibreboard made from Scandinavian recycled chipped softwood together with waste newsprint to provide a breathable sheathing board to the external walls and roof.
12. OSB: Oriented Strand Board made from thinnings from managed plantations (FSC); the process utilises 95% of the wood, discarded bark being used for fuel in horticulture.  Used for internal racking walls and first floor sub-deck.
13. Glulam Beams: Small sections of timber from sustainable sources glue laminated to provide a larger structural grade timber.  Used for cantilever, around glass floor and over larger openings as lintels.
14. Earthwool: insulation to acoustic separating floor (where breathability is not required).  A+ Generic BRE Green Guide rating.  Made using recycled materials.  Made from rapidly renewable organic materials. No added formaldehyde binder.  No added dyes.  Up to 70% less embodied energy and recyclable.

The existing cabin and hard surfaced garden offered little in the way of ecological benefit.  The new buildings green roof provides 92 sq.m of biodiverse green roof with 16+ varieties of sedum.  Already birds, butterflies and bees have been taking advantage of the green roof.   The garden has been designed to increase permeability and green areas with a minimum of 17 plant species and mature hedging, resulting in a net ecological and biodiversity gain.

Whilst it was not a building regulation requirement to exceed U-values sustainability was a key decision in our clients commissioning ARCO₂.  The thermal performance exceeds that of the former house and cabin.  Improvements to the existing building were also made to greatly improve performance including a new high efficiency Sedbuk A rated heating system, insulating the first floor/exposed walls, installing underfloor heating, new windows and acoustic insulation, helping to provide thermal separation between floors.  An improved MVHR ventilation system ensures that all wet areas meet and exceed building regulation requirements, moderate humidity and provides heat recovery.

U-Values:           Floor: 0.15               Walls 0.19 & 0.21 (entrance walls)           Roof: 0.16                Windows 0.67 – 1.0

The main challenges were the logistics in terms of delivering materials to the site, demolishing of the existing cabin, machinery for excavations, retaining excavated material and the exposed location.  As previously mentioned other challenges included the re-diversion of the SWW main, retaining walls and Party Walls.

Architects Working Across Cornwall

ARCO2 designs contemporary sustainable homes across Cornwall, including North Cornwall, South Cornwall and coastal locations such as Polzeath, Rock, Padstow, Mawgan Porth, Falmouth and beyond. Our work combines contemporary architecture with low energy design principles, carefully responding to landscape, climate and long-term building performance.

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