High ambition – The Beacon, Hemel Hempstead

The Beacon, shortly to begin construction in Hemel Hempstead, is set to be the world’s most sustainable residential tower. James Parker spoke to the project’s architect to hear about this proposed model of luxury eco-living.

The Beacon is an ambitious sustainability project in the UK residential sector in its own right. The 17-storey tower by developer Lumiere Developments is also a statement by a firm looking to make its mark and, as the name suggests, create a model for others to follow.

Lumiere’s mission is to “promote large-scale uptake of renewable energy,” and this pioneering zero carbon scheme, which is about to start construction on a site near the A41 in Hemel Hempstead, brings a number of technologies together towards meeting this goal.

The scheme comes with a host of big claims – the firm says the Beacon will be the “world’s most sustainable residential tower” thanks to a highly-insulated concrete construction – hoped to deliver 40 per cent energy savings – and a range of other measures. Lumiere is also promising “free energy for life,” and the first electric car and bike share scheme of its kind. And at less than half an acre, the site’s small footprint is helping support the project’s claim to have the highest density ‘solar farm’ yet seen – the building will be covered in PV panels.

While all this might sound a bit too good to be true, Lumiere’s project architect Nik Vyas is deadly serious about delivering on the project’s aims. And with the building having received detailed planning permission and over 40 per cent of the flats reserved, the proof will soon be visible.

He says the development is unprecedented in the UK, however:

“We are trying to create a shift in the industry. I have never worked on a building with such high sustainability credentials, and to be frank that’s because there aren’t many.” He adds, however that there have been doubters: “Naysayers are saying you can’t build a zero carbon building of this type on this site at an affordable cost. People say it’s going to cost you a fortune, but according to what we have done so far it’s not; it can be built for the same price as social housing.”

The developer is looking to tap into strong consumer interest in sustainable living, but also to attract a wide range of demographics including those seeking luxury. The 272 apartments range from £217,950 for a one-bed up to £524,000 for a three-bed and penthouses at around the £1m mark, and will be high-spec throughout.

One of the most innovative aspects of the building is the ‘cooperative’ lifestyle concept that Lumiere has formulated, which residents need to buy into in order to get the full financial benefit, such as renting their cars from the developer and using facilities within the building such as the gym and cinema.

One of the project’s key selling points – that of being able to save residents £11,000 a year on bills – is predicated on using all of the available services. It is even hoped they will be able to reduce management fees they pay in so doing, as a result of the profits being returned back to the building.

Vyas believes this is another rare aspect of the scheme:

“The big idea is trying to create a social equilibrium between all residents – I’ve never come across that before.”

He reveals some passionate views about the potential of sustainable buildings, but also the relative lack of such buildings of this scope in the UK residential sector, views which have helped provide impetus for pushing the envelope on the Beacon. “The solutions to end energy poverty are there, but no-one’s ever really tried to answer the questions on such a grand scale.”

Vyas adds:

“It’s our job to show the industry that it can be done, and to raise the question of why aren’t people doing it.”

He quotes WHO statistics which show seven million people die from air pollution each year and says that such figures, in the context of the fact that buildings account for 40 per cent of harmful emissions, are key drivers for Lumiere, not simply maximising profit margins.

Brownfield regeneration

The former brewery site a mile south west of the centre of this London commuter belt town was acquired by Lumiere in 2012 and currently holds an empty four-storey office building.

Hemel Hempstead was named ‘the UK’s ugliest town’ the year after the site was acquired for development. However, the Beacon sits at the centre of the Hemel Evolution regeneration programme, and is adjacent to 400 acres of protected Boxmoor Trust green belt land.

This helps explain why there has been a large amount of interest among buyers, in addition to the combination of sustainability and luxury living, and the fact that the town is 24 minutes from Euston station.

The use of a brownfield site bolsters the project’s sustainability credentials further, as does its comprehensive recycling strategy. The soft strip and soft demolition of the office building on the site has already been undertaken and materials will be, where possible, recycled in other buildings, including the new tower.

Materials that have been reused elsewhere include cedar cladding, and Lumiere has reused fittings such as air con and VRV units, doors and frames, locks, ceiling and carpet tiles, cables, furniture and decking in its own office. Once the hard demolition is complete, the superstructure will be reused as aggregate for tower construction plus access roads.

Building form

The tower has been designed to not only offer a high degree of air-tightness and a lightweight construction but also with a focus on aesthetics, says its architect. According to Vyas, beauty has not always been linked to sustainable design:

“There are sustainable developments which don’t look that great or exciting – I think this will be a stunning building from far away, and up close.”

Following extensive research into how to create a lightweight in situ concrete tower block using fewer materials, the design team rejected an original scheme with the traditional in situ concrete columns and slabs, and opted for an innovative, largely column-free design with substantial 145 mm walls instead. Vyas explains: “After some serious interrogation of the figures from the structural engineers, we produced a design where all of the partitions within apartments are structural – that creates an incredibly rigid building.”

He adds:

“Having so many intermediate levels of support also means all of your slabs can be a lot thinner than on a conventional multi-storey building.” As a result the only columns are a handful on the ground floor, and slabs are only 175 mm, meaning a reduced use of concrete overall.

Walls between apartments include two layers of plasterboard plus Rockwool insulation, the result being, says Vyas, much better acoustics than social housing and student accommodation projects he has visited, where “you can hear people two apartments down.”

From the first floor up, there are continuous ‘solar’ balustrades with PV panels angled at 38 degrees to optimise their exposure to sun year-round. This will present a somewhat unusual facade of skirt-like ribs of sloping PV balustrades with generous punched windows between, but which will not affect residents and, says Vyas, presented no issue for the planning department. In addition, the PVs will all be maintained externally, and that very few panels will need to be replaced over the tower’s lifetime, according to the architect.

The building steps back slightly above floor 13 with penthouses clad using quadruple-glazed curtain walling glazing panels. Storeys below will all have triple-glazed windows, assisting in the building’s overall U-value of 0.1 W/m2K achieved through a significant volume of Rockwool insulation. While the building will be designed to be highly air-tight, the windows will be top-hung and openable. This means the building’s high level of thermal performance can’t quite reach the heights of Passivhaus. However it’s expected that residents will see a reduction in heating costs of 70-80 per cent.

Vyas explains the reasoning:

“People do like control – if it’s a hot day, they may want some air. People still have to be comfortable in their home and some like fresh air and some don’t – it’s not up to me or the developer to take that away from anyone.”

Construction will be scheduled in a highly efficient way – all concrete will be formed at the same time, including upstands and partitions – once the third storey is underway the first fix will be able to commence on the two levels below.

This means “very concise sequencing as building progresses,” says Vyas, adding “you don’t have to wait for the whole building to be cast in order to put glazing panels in; it dramatically reduces construction time.”

He says that the design team “sees all of our subcontractors as partners – an integral part of the team.  They can use our offices in Rickmansmorth whenever they want to.”

He adds that the developer’s strong CSR policy is shared with subcontractors to get them to buy into the values, such as on recycling of materials.

Atrium & interiors

A central atrium containing an arboretum will enable access to apartments via glass lifts. The atrium’s key design intent is “an attempt to provide quality of air within the space,” says Vyas. The design team is currently working out whether it can be topped with an ETFE roof,  but he says this is a favoured option “because it has better sustainability credentials than glass and is maintenance-free.”

The ground floor is where the main amenities for residents are located, from the internal arboretum to the cafe and bar area, water features, club lounge and cinema room as well as external patio space. In addition, on the first floor will be a 2,120 ft² gymnasium, and a communal roof garden will also provide an outdoor residents decked ‘library’ area and an ‘observatory.’

With the aspiration being to attract high-end customers as well as those seeking affordable options, interiors will be high spec with wood-floored hallways and open-plan living areas featuring ceramic tiled floors and walls. Living spaces (floor to ceiling 2.7 metres, and in penthouses 3.1 metres) open on to private balconies through full height patio doors and windows.

Fully fitted kitchens will feature energy efficient A+++ rated appliances, and other energy efficiency features will include smart-controlled thermostats, comfort cooling systems and automated blinds. Penthouse apartments will have substantial terraces including winter gardens, hot tubs and electric privacy glass.

The developer is actively trying to encourage residents to discard their cars with its what’s claimed to be a pioneering rental scheme. However there are 319 car parking spaces packed into a tight basement area, thanks to an APS robotic system which stacks cars efficiently, enabling high density parking.

Renewables

In addition to the solar PVs producing a large chunk of the building’s electricity, ground source and air source heat pumps will provide heat for water, and the building’s ceilings will be cooled using a recycled greywater system. In fact all water used in the building will be either rain or greywater harvested; no water will come through the mains, which is projected to save around five million litres per year.

“There are five huge tanks in the basement” says Vyas, adding that all of the appliances “have been carefully considered on water and energy use,” and from toilet fittings to kitchen units they generally range from A+ to A+++.

In addition to the MVHR system sucking up extra solar gain in the building, heat will also be recovered to warm harvested water: “The more heat we get into space the more energy we produce,” says Vyas. He says this would obviate normal concerns with heat gain from an ETFE roof, adding – “people normally put a fridge on the roof. However with our system the more heat we get, the more heat can be recovered and used.”

Measurement

The building is one of the first in the UK to be assessed under the BRE’s new, comprehensive five-star ratings system for housing, the Home Quality Mark. It is no surprise that the architects are hoping to come out with a five-star rating, covering criteria such as comparative running costs, environmental footprint, amenities and wellness. Given that the building is relatively close by the BRE in Watford, it’s likely its academics will take a close interest in the results, to see if turns out to be the exemplar it promises to be.

Whether or not it is eventually confirmed as the world’s most sustainable apartment block, residents will be receiving copious amounts of information on how their investment is performing, This data, ranging from wind pressure to heat gain, and gathered from sensors placed during construction, will also give the developers crucial knowledge on what is working and what could be further improved on.

Although detail packages remain to be ironed out in the design, this potential game-changer of a project has already provided the blueprint for Lumiere for its pipeline of future residential schemes, including in Hemel Hempstead.