Developing the UCL Ear Institute roof garden

A team in the UCL Ear Institute were highly commended in last year’s UCL Sustainability Awards for their sustainable roof top garden. Graham Nevill, who co-led the initiative, reflects on the creation of the garden as a place for relaxation and recreation.

The Ear Institute was created in 2004 using part of the site of the now closed Royal National Throat Nose and Ear hospital on Gray’s Inn Road.

On the third floor is an open roof terrace which after the purchase of tables and chairs is often used by staff for lunch breaks and occasional work-related gatherings. It is an open area of concrete tiling that presents a hard uninviting aspect especially as the area, although surrounded by a low perimeter wall, is often exposed to full sun and can be quite windy at times.

The department is making moves to address sustainability by various initiatives but what we felt was needed was a definite greening of the roof space, not only to give staff a more welcoming area but to encourage, albeit in a small way, an increase in insect biodiversity by creation of a roof garden designed to encourage local fauna.

It was not considered in keeping with sustainable principles if we just went ahead and bought from a supplier all the necessary timber which would also be quite expensive. We designed a garden consisting of five, one metre square raised bed planters made from discarded wood pallets which were found within easy walking distance from the Ear Institute.

Four pallets would be used for each bed by standing them on end and securing the resulting square by drilling together with batons. These were then painted in a weather resistant wood paint and the inner surface wrapped with black weed proof membrane and inside was placed a durable, thousand litre builder’s hippo bag.

It was a bit of a struggle to find a supplier for bagged soil who would deliver to the area as many would bulk deliver, but only onto the pavement. Eventually soil was sourced that proved to be excellent, a heavy mixture of rotted manure and compost that would hold moisture far better than normal garden compost. We thought it would be excessive both in weight and cost to fill each hippo bag fully and so, since most plants will only need the top third of the bag to root, we decided to fill the bottom two thirds with inert material followed by rotting wood to facilitate slow nutrient release, then topped with a square of turf to stop the soil falling through.

We created a planting scheme that used plants able to resist the drying conditions, examples were either bought from Camden garden centre of from donations from staff members gardens. When plants had been added to the beds, a layer of wood chip was added to mulch the surface to reduce water loss.

We always recognised that watering would be an issue as there is no tap on the roof, the only source being the lab below and a number of trips up and down stairs to do the watering. To provide an immediate source we constructed a rain water collection point consisting of a large flat collection surface running via some discarded guttering into a normal black plastic covered dustbin. The water does tend to be used up quite quickly in hot weather so we are still having to occasionally bring water up from downstairs.

While the roof has now been made a more pleasant place for relaxing there was still the problem of a lack of shade in the heat of the day. Creating a large amount of shade was never going to be possible mainly due to the windy nature of the roof damaging any structure and parasols were considered unsuitable as they could blow off the roof.

A limited solution was the creation of a shaded corner using the height of bamboo plants planted into a similar arrangement as the main beds. A central focus was a small solar powered water fountain set into pallets around which was placed pallet seating with a carpet covering and cushions fashioned out of foam packaging. We felt this would fit into the college aspiration of creating a relaxing wellness space for people to gather around. So far the work has been well received and a spacious but sterile area transformed into a welcoming and relaxing space that hopefully, does at least a little to encourage wildlife into the local area.

Wild Bloomsbury

UCL is working in partnership to create a ‘Wild Bloomsbury’: improving biodiversity, supporting wellbeing, building climate resilience and reducing air pollution for our local community. With our goal of creating 10,000m2 of extra biodiverse space by 2024, we have the opportunity to demonstrate the benefits of nature based solutions, while forming strong community partnerships and making a better Bloomsbury for everyone. Find out how you can get involved