A collaboration between Chartered Architectural Technologist Mark Wright MCIAT, and building owner, Engineer, and Building Management System manufacturer, Joe Miles CEng, this new building uses Joe's Atamate Smart-Building Management System to achieve better than Passivhaus performance from a vapour-open building envelope of mostly natural materials. Build cost: £650,000
This new apartment building demonstrates an innovative solution to the endemic problems of dilapidation, and lack of fitness for modern purposes, of much of the terraced housing in Britain. An adjoining pair of houses were demolished and replaced with a new building to provide 14 bedrooms in 6 apartments, each with private outdoor space. Demolition allowed a holistic building technology strategy to be implemented from the ground up. The internal environment of the building is extremely fresh and open feeling, and outdoor spaces are generous. Tenants are very happy and flats let quickly. Individual flats, with excellent sound proofing, and state-of-the-art door entry systems, gives every assurance to vulnerable tenants who are not well served by traditional student lets.
Minimise energy demand - lettings to be offered inclusive of services.
Flats not houses - to suit less social students looking for higher levels of comfort and security.
Designed for Atamate - intelligent control system for heating, ventilation, lighting, security etc.
Optimised for Ecocent - extract ventilation air-source heat pump, and hot water cylinder system.
Vapour open construction - reduce vapour pollution load for more efficient ventilation.
Airtight - a sealed building to be ventilated by centralised extraction and passive air intakes.
Natural local materials - Atamate is a Welsh company with strong ethical and local values.
Buildable by the lettings business’s building and maintenance team - avoid specialist trades.
Adaptable - Free spanning construction with non-structural partitions.
Outside space - Each flat to have access to a usable private terrace.
Smart Apartments - Finalist AT Awards 2021
Architectural Design Response The front elevation shares the general proportions of the neighboring houses, but is built without ornament. The flush-set windows, and contrasting bright colours elevate the differentness of the facade, but the result is that the building fits extremely well into the terrace. The familiar pitched roofed appearance of the rear outriggers is preserved, but the gap between them is fully utilised with a unified building footprint. The roof behind the gable ends is built flat, to provide two very large open roof terraces for the top flats. The first floor flats enjoy roof terraces built onto the roofs of the single storey extensions of the ground floor. Square windows challenge the oblong orthodoxy for a futuristic finish to the rear courtyard gardens.
14-16 Cogan Terrace Aerial View
Atamate Smart-Building Management System
An Atamate Smart-Building Management System monitors the building using a network of sensors. By controlling a system of variable air intakes, skylights, extract air heat-pumps, and panel heaters, it intelligently manages the internal environment of the building in response to occupational factors such as breathing, cooking, and washing. The system also manages hot water production, and provides an interface for the lighting, sound, security and door entry systems, with a smartphone app for building users. Machine learning is used by the system to continuously improve building performance. The system is remotely accessible for performance monitoring, and administration of the entry system etc. Atamate is based and made in Wales.
Building Technology Implementation
In densely occupied and gadget-packed student flats, internal heat gains are very high, and in the moderate Cardiff climate, fabric losses are low. Cooling is therefore a more significant factor than heating. Rather than being recirculated in the winter, and dumped in the summer by an MVHR system, heat extracted from exhaust air is harvested to produce domestic hot water, which would otherwise be the single most significant energy demand. This task is performed by two Ecocent heat-pump systems from Earth Save Products in England, which have performed very well with the Atamate system.
To optimise the design for ventilation, rooms required to be ventilated using depressurisation are all designed with access to an external wall. Kitchens and bathrooms, which are ventilated by direct mechanical extraction, are placed centrally in a deep floor plan. Kitchens are provided with lightwell skylights that provide natural illumination, and ventilate the rooms with fresh air.
Electrically actuated fanless ventilation apertures, and 12 electrically actuated skylights, provide fresh air directly to all habitable rooms, but only as required for health and wellbeing. The Atamate system continuously monitors air quality, and balances extraction requirements and incoming fresh air distribution. It manages the individually controllable vent openings to provide a constant, healthy, internal environment. This Demand Controlled Ventilation (DCV) gives very significant energy savings and comfort improvements in comparison to regular trickle vents.
A breathable building fabric minimises humidity build-up, and consequently, reduces necessary infiltration of fresh air required for human health and comfort. The breathable walls are inherently airtight (Durisol). Roofs are carefully sealed with Solitex breathable membrane and Tescon Vana airtightness tape. Even with difficult junctions with existing buildings mid-terrace, the building has sufficient airtightness for a mechanical ventilation system to operate effectively (3ACH@50Pa). A significant amount of time was invested in the devising of construction detail drawings showing the complex interaction of the structure, insulation, and breathable membranes. These gave great assistance to the construction team, who were initially inexperienced with the new technologies. In the course of the project Mark Wright studied and qualified as a Certified Passivhaus Designer, which helped a lot with the task of detailing. To provide the most consistent and manageable internal environment, and to minimise the risk of overheating, solar energy gains through windows are minimised. Window sizes are reduced where possible, and are fitted with triple-glazed low emissivity glass.
In an apartment building, sound insulation is critical to the good mental health of occupants, particularly for students concentrating on their work. A 225mm solid dense concrete block wall separates the two halves of the building. Lewis-deck, a lightweight screeded profiled-metal-deck floor system with vibration isolation, gives exceptional noise reduction with a thin build-up. Lewis-deck was also used as a working platform before screeding, speeding construction and allowing for an uncluttered, scaffolding-free work site. The deck was formed on a free-spanning Posi-joist floor. A great deal of timber was saved by the open-web design of the joists, and the project team enjoyed the easy fitting of the complex building services.
Durisol Insulated Concrete Formwork
Lewis Deck Profile Metal Decking
Solitex Plus Breathable Membrane
Many options for the construction of the building envelope were considered - prefabricated SIP panels, prefabricated timber frame, on-site timber, and various formworks were all dismissed for reasons of cost, performance, etc. Durisol insulated concrete formwork is an Austrian product with a manufacturing plant in Wales, and was chosen for the project for its ease of construction, breathability, thermal mass, fire performance, largely natural origin, local supply, and local technical support. This formwork block system is made of open-textured recycled wood strands cemented with lime. The hollow blocks are partially filled with PIR insulation. A space in each block creates a matrix of voids that are filled from above with fibre-reinforced concrete slurry. The resulting wall is vapour-open. The external walls were built of Durisol by carpenters and general hands. Additional reinforcement was designed by Mark and Project Engineer, Howard Austin, based on the monoliths of Stonehenge; the front elevation is structurally independent of the neighbouring houses, which simplified the build and eliminated thermal bridges that would have been created by traditional lintels. Durisol was found to be excellent, and is now a first choice for every new project the team undertakes. The roofs and roof insulation are built using an i-beam and woodfibre system provided by Steico. The jazzy-coloured exterior finish of the buildings is Ty Mawr Glaster lime render made in Wales. As with Durisol, local technical support for the innovative new product was a real bonus. Glaster lime render contains crushed waste glass as an aggregate. This saves using primary sand for the render and gives a use for waste glass, for which there is very little demand in the UK. The walls also have a sparkling sheen as if they were glittered! It is proving very durable.
Ground Floor Interior
Review The building has been assessed in a peer reviewed post-occupancy study by Oxford Brookes University. Using Atamate to manage the complete suite of building services, in a building designed around them, total annual energy demand has been recorded as 12kwh/m² - better than the Passivhaus Standard of 15kwh/m². Our strategy could perhaps be coined ‘Activhaus’, or ‘Fabric Last’, as solar gains and fabric performance are not the story here at all. Having said that, although the ultimate insulation potential of the building fabric is constrained by a small footprint, and the decision for vapour-open construction, the fabric is very well insulated, and in Cardiff's moderate maritime conditions, fabric losses are extremely low. Space heating demand (as little as 300w per room @ ΔT 23°) can be provided by simple small electric panel heaters. As domestic hot water is heated by the Ecocent extract-air heat pumps, a gas connection, with its attendant fees and inspections, has been avoided. The breathable building fabric does effectively reduce humidity build-up, which is an important factor in Cardiff’s seaside climate.
As an innovative low energy building, 14-16 Cogan Terrace is exemplary. As a project, it is an outstanding demonstration of a collaborative client/technologist relationship. That relationship is testament to the value of trust in emerging new talent shown by a client, and also to the power of dedication to excellence shown by a developing technologist. Joe and Mark enjoy an ongoing and fruitful working relationship; two self-made professionals operating at the edge of innovation in building technology.
Mark Christopher Wright BSc MCIAT
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