This is the first in a series of articles that look into the battle over daylight currently raging in London. Daylight is the source of all life on earth. It is fundamental to our quality of life. How we plan our buildings to ensure access to good levels of daylight is an extremely important but often overlooked part of planning.
The impact of poor quality daylight on health has been known about for hundreds of years. It is a cause of disease such as rickets, which used to be common in London and many other urban centres. Because of this, legislation from the early 20th century progressively sought to improve the access to light and air by laying down rules for maximum heights of buildings, and the minimum distance they must be set apart.
But today, much of that has gone out of the window. London is seeing a wall of skyscrapers about to hit it, with 436 tall buildings in the planning pipeline. Some will be just meters apart from each other, putting parts of London into permanent shadow. These buildings will have a severe and permanent impact on the level of daylight received by tens of thousands of homes, condemning the residents of those homes to be poorer in both health and wealth.
To understand the seriousness of the change, first let’s consider how we measure the impact new buildings have on daylight. At times this may seem overly technical, but stick with me, it is important.
Under the modern planning system, instead of having rules which mandate the hight and form of buildings there are policies which mandate the protection of residential amenity, and that includes access to daylight and sunlight. It is a more outcomes based approach. It means that councils, when making a decision on a planning application, should take into account the damage on daylight and seek to protect the daylight of existing residents – but how do we know what damage a building will cause?
For larger schemes, developers are compelled to produce an environmental impact assessment. This sets out what the impact of a development will be on (you got it) the environment. This includes assessments on wind, daylight, biodiversity, views – anything that affects the environment.
The decision maker is then supposed to make their own mind up about whether any impact is acceptable or not.
But there is a problem. Environmental impact assessments, which go into technical details on every aspect of environmental impact, are huge. I would be shocked if any councillor making any planning decision has ever read an entire copy.
This is a particular issue when measuring daylight. Experts measure the amount of light hitting each individual window using a computer model. On their own, the figures from these models are difficult for the layperson to understand. They can tell you the quantity of light lost to an individual window, but how is a part-time decision maker (a local councillor) supposed to come to a view about whether that loss is significant, perceptible or acceptable? To illustrate the problem let me ask you this. How do you think you would feel if your windows dropped from a vertical sky component value of 29% to 27%?
Clearly, these figures need some interpretation if they are going to be meaningful.
The Building Research Establishment used to be a government agency dedicated to researching (you got it) buildings. It is now a private company in a similar line of business. They produce a guide to assessing daylight for planning purposes. That guide has been adopted by most local authorities as the way in which the daylight impact of new buildings should be measured.
That guide includes a set of criteria which if broken mean that there will be a perceptible loss of daylight to the inhabitants of a room, below the level at which that room is considered to be well lit.
So if the BRE criteria are met, there will be either no perceptible loss of daylight or the condition after the loss will still result in a well lit room.
If they are not met, if the BRE criteria are broken, then the inhabitants of the room will notice the loss of daylight caused by the new building and the loss will cause a relatively poorly lit room. There are two tests in the BRE guidance which measure slightly different things. One test VSC, looks at the amount of light entering a window, the other NSL looks at the distribution of light around a room. If either test is broken that is considered a breach of the BRE guidance.
These criteria make determining the impact of planning applications much easier. If a large number of windows are in breach of guidance a large number of people will experience real harm to their quality of life as a result of a new building going up. It is then up to the planners to decide whether that loss is acceptable, but a significant loss of daylight should be a particularly important factor weighing against the grant of planning permission.
A second set of criteria are produced by the British Standard. The British Standard is a body which produces standards for all sorts of things. The daylight standard uses a metric called ADF or Average Daylight Factor. These are not appropriate for determining the impact of new buildings on existing buildings as they take in a whole range of variables. Many of these don’t have anything to do with a new building appearing in front of your window.
However, ADF standards are used for the new buildings themselves, to look at the amount of daylight that should be available for future inhabitants of the new building if that building is to be considered up to standard. They are therefore expressed differently, as a bare minimum level that should be met.
The impact of Skyscrapers in London
So how much do all of these skyscrapers damage daylight conditions in London? The answer is a lot.
Wood Wharf is a new development on the Isle of Dogs. It is a major new residential development being taken forward by Canary Wharf Group. As part of the planning application the developer assessed the impact of the development on 2153 surrounding windows. Of them 785 failed the first BRE criteria, 208 rooms failed the second.
The developer also measured how the new skyscrapers would impact surrounding residents against the British Standard. In other words, they looked at whether the loss of daylight caused by the new development would cause existing buildings to fall below the amount of daylight that should be available in new buildings. At Wood Wharf, the loss of daylight would cause 47% of the homes surrounding the development to fall below the ADF standards required for new buildings. In other words, the development causes large numbers of homes around it to become sub-standard.
Other new developments on the Isle of Dogs have similarly devastating impacts. Heron Quay West causes 730 individual breaches of the BRE tests. The proposed Colombus tower causes 60% of surrounding homes to fall below the ADF minimum for new buildings.
And it isn’t just the Isle of Dogs that is being cast into darkness. This is happening all across the capital.
In Southwark a new development proposed for Blackfriars has a particularly nasty impact. The set of tall buildings being built by Barratt’s is surrounded by social housing, most of which will be plunged into darkness by a new development of luxury homes called Blackfriars Circus.
On the other side of Blackfriars Road from the new development is the Blackfriars Estate. Built in 1871 it was one of the first Peabody housing estates. As a result of the new buildings some blocks of the estate will see 80% of the homes fail the guidance, with large numbers seeing their daylight being reduced by more than 40%.
Behind Blackfriars Circus are a group of relatively new buildings that were built to house people being moved from the Heygate Estate. Some of these homes will see their daylight reduced by 90%. What will be particularly galling for these people is that the Heygate was relatively well designed in terms of daylight and sunlight with the large residential blocks being well spaced. The people in these sites, called the Elephant and Castle Early Housing were in come cases compelled to move from their homes, and now will face years living next to a building site, watching vast walls being constructed in front of their windows.
A dark new world
The problem is not limited to the impact on existing residents. Sometimes new buildings are planned so close together that the daylight in the new buildings is wildly below standards. The Shell Centre development, on the South Bank, another Canary Wharf Group development, will see some tall buildings just 8m apart from each other. The result is that 25% of the new homes being built will fail the minimum daylight levels recommended under the British Standard.
The poor daylighting matters little to the developer, as the worst impact is in the affordable housing that the developer is building on the lower floors of the Shell development. To the delight of Lambeth Council, who spent hundreds of thousands of pounds of public money promoting the scheme, this affordable housing is being reserved for the elderly, people who arguably need access to daylight most.
The battle for light
All of these examples were granted planning permission. For whatever reason planning authorities deemed the damage to daylight for existing residents, and the poor quality amenities for future, poorer residents in affordable housing, to be acceptable.
Of course, although people living around skyscrapers will see their homes become darker, more expensive to heat and gloomy, those living on the high cost upper floors of the new buildings will no doubt have great access to daylight. In real terms these planning permissions transfer health and wealth from the existing residents surrounding a building to the wealthy residents of new luxury homes.
The battle over daylight is not simply about making homes ‘nice’. It is a conflict over an important natural resource.
Why local authorities continue to grant planning permissions that so obviously act against the interests of their voters is the subject of my next article.