Shaftesbury’s Sustainable Retrofit at 22 Ganton Street

Situation

Shaftesbury is a property investment company, which focuses exclusively on the West End of London. 22 Ganton Street is six-storey building, just off London’s iconic Carnaby Street. Originally built in around 1920, it has been owned by Shaftesbury since the mid-1990s and was previously refurbished in 1999. It is a multi-occupied building, which now includes Shaftesbury’s new London Head Office.

The project team comprised architect MR Partnership, project management firm Single Point Project Management, main contractor Blenheim House Construction, and mechanical and electrical consultants Watkins Payne Partnership. Together, they transformed the existing building, remodelling the reception area, refurbishing lobbies, stairs and toilets throughout, upgrading windows and cladding, creating a duplex office space on the two top floors and introducing new terraces, including a green roof, green wall, seating and decked areas.

Actions

Energy

• Mechanical ventilation heat recovery, requiring around 50% less energy than heating outside air
• Low energy lighting including LED lamp sources, 50% more efficient than required by Building Regulations
• Lighting control system with automatic daylight dimming and occupancy detection (motion sensors), 25% more efficient than previous manual switching
• A+ rated insulation materials cutting heat loss, including green roof, cavity insulation, plasterboard, duct wrap and pipe lagging
• Energy sub-metering for lighting, small power, lifts, fresh air units, air conditioning units and all occupied areas.

Water

• Water saving fittings, including low flow taps at 5 litres per minute and dual flush toilets at 6 / 4 litres
• Valves linked to motion sensors in toilet entry areas, shutting off the water supply when areas are unoccupied
• Water sub-metering with pulsed output installed where the water demand exceeds 10% of total consumption.

Materials

• 99% of the existing building structure and 80% of the façade retained
• 99% of new insulation certified responsibly sourced
• Most existing timber retained, including all the roof structure, 95% of bannisters and 90% of skirting boards
• 86% of new timber purchased from certified sustainable sources
• Recycled aluminium and steel specified as part of the design.

Ecology

• Extensive green roof, comprising a vegetation blanket featuring sedums selected to flourish in the UK climate
• Green wall with bird boxes, bird feeders and a range of plant species, such as Catlin's Giant, winner of the Royal Horticultural Society's Award of Garden Merit, the lesser periwinkle and great wood-rush
• Wildflower areas on the green roof, increasing floral species and providing foraging resource for widespread invertebrate and bird species
• Patches of bare ground and stone on the green roof, benefiting species such as butterflies, bees and wasps
• Insect hotels, benefiting ladybirds and other bugs.

Health and wellbeing

• All workstations within seven metres of a window with a view out
• All office lighting carefully zoned, so workers can control light levels for zones of up to four workplaces, and workstations next to windows separately zoned and controlled
• Heating and cooling system allowing occupiers to control zoned areas in all occupied spaces
• Lighting levels in line with the CIBSE Code for Lighting, with consideration for areas where computer screens are regularly used, e.g. avoiding screen reflections
• Thermal comfort levels in line with CIBSE Guide A – Environmental Design recommendations
• All fluorescent lamps fitted with high frequency ballasts to reduce the risk of issues related to flickering lights.

Management

• All mechanical and electrical commissioning in line with good practice guidelines, including BSRIA and CIBSE
• Considerate Constructors Scheme score of 35/50, ahead of the 32/50 target, with all areas rated Very Good, covering care about appearance, community, environment, safety and workforce
• Building User Guide for areas including environmental strategy, energy, water, transport, materials, waste and refits.

Financials

• £4 million total project cost
• 8% return on total investment
• Enhanced rental income, with space leased quickly at good market rents
• Energy cost savings for occupiers.

Shaftesbury did not specifically analyse project expenditure in terms of potential additional costs for efficiency measures. These are part of business as usual for the firm on refurbishments, with new technologies and products delivering efficiency improvements, and Shaftesbury aware that the occupiers it wants to attract expect modern office space to be both comfortable and efficient.

Benefits

Enhanced occupier appeal, increasing rental value and lettability, as well as attracting Shaftesbury to relocate to the building:

• Healthier, more contemporary indoor environment for workers, with new lighting system that is both attractive and efficient
• Outdoor terraces with seating, planting, green wall and views across London, as well as ecological value
• Exposed services enhanced lettability by giving a sought-after look, whilst also reducing materials use.

Supporting occupiers’ sustainability goals, including Shaftesbury:

• Enhanced ecological value, with the creation of 140 sq ft of species diverse green space, described in the BREEAM report as a ‘new, locally-relevant, ecologically valuable habitat’
• Improved operational energy efficiency, cutting CO₂ emissions
• 8% less water consumption per person than the BREEAM requirement, at 5 m³ per person per year
• Stronger sustainability credentials, achieving BREEAM Very Good and an EPC B rating, previously unrated.

Additional benefits for Shaftesbury:

• Reduced construction costs and environmental impacts, through the retention of 99% of the building’s structure and 80% of its façade, as well as the re-use of a significant proportion of timber in the building
• Reduced exposure to the Government’s Minimum Energy Efficiency Standards, which come into force in 2018.

Find out more

Rob Kirk

Portfolio Executive

Shaftesbury

 

www.shaftesbury.co.uk