Do Daylight and Sunlight Rules Need Updating – Yes Bluntly

Today in the Sun we find that Javid is keen in the Housing White Paper

Sajid Javid wants a major relaxation of strict practices that stop new homes being built higher than their surrounding buildings…

the Cabinet minister also wants to review rules on light that stop building if neighbouring homes are cast in shadow.

A bit of history – the BRE guidelines from the 1960s were based on two storey dwellings and were widely criticsed as such, especially in London, where it became a battleground at every high density scheme.

Of course there are now laws or regulations in the UK on Daylight and Sunlight, unlike most European countries, it is a convention.

In 2011 under pressure the BRE revised them, a few years earlier I asked a daylighting consultant why the government had never asked for a review – the answer none left at the then DoE had the foggiest idea how to apply the standard.

In 2013 the GLA issued its own review recommending some relaxation in London.

NLP in 2013 wrote

Is the BRE’s daylight, sunlight and overshadowing guidance needlessly inhibiting the delivery of new homes and stifling good urban design in London?

The planning process undoubtedly plays an important role in protecting residential amenity from unacceptable development. For many developers and architects, though, the BRE daylight and sunlight guidance provides an overly restrictive basis for the assessment of natural light within much of London. Predicated on a suburban model of development, the guide sits uncomfortably alongside a wider policy agenda focussed on making optimal use of urban land and maximising housing delivery in the face of London’s acute housing supply crisis. Its guide levels are inconsistent with expectations of natural light in intensively developed urban locations and are frequently incompatible with good urban design for higher density environments.

Is the BRE’s daylight, sunlight and overshadowing guidance needlessly inhibiting the delivery of new homes and stifling good urban design in London?

The BRE guide does highlight the advisory nature of its recommended levels and the need for flexibility and professional judgement in their application. All too often though, planning officers see the guidance as a set of mandatory standards to be rigidly and uniformly enforced. The guide also encourages third party objections to planning applications as neighbours interpret its indicative targets as hard and fast rules. All of this serves to frustrate and delay otherwise acceptable development and inhibit the delivery of new homes and jobs.

It is interesting to speculate how such a mechanistic application of the BRE guide would today inhibit the creation of some of London’s most valued townscape and enduringly popular housing.

Of course postwar planners criticised Victorian layouts for neglecting sunlight and being rookeries, however estates planned rigidly around the primitive daylighting norms of the 50s all looked like they were traced from the daylighting handbooks of the time (look at CLapham Park Estate for example)

English rules were copied in many emerging economies such as Hong Kong and swiftly abandoned.  They reviewed the rules recently and allowed a minimum vertical daylight factor of 8%, however the closely related vertical sky component in the UK is 27%, and the GLA recommend mid teens.  (VDF includes reflected light and can be measured with a handheld instrument and simulated in renderers such as lightscape and radiance, it is much better).

So it is too strict by international standards for high density areas.

What we need from a review is a tiered standard

Towards 20% low to mid rise areas

15% Urban Density Areas

Or as a rule of thumb being able to come off at closer to 45% from back of plot – rather than 25% – as allowed in Japan and Montreal for example, would add much needed flexibility.

Around 10-12% High Density Areas, which would then allow streets and clusters of high rise residential not just stand alone in poor green space.

Such approach would be better than ‘higher than your neighbour rules’ as what if then everyone tried to apply them without limit.

Oh and lets scrap antient lights (yes it is spelt like that) whilst we are at it.

Japans Run and Rise Height Restriction

Japans Run and Rise Height Restriction




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