Issue 42 summer 24 web - Flipbook - Page 108
Shedding Light on
Conservation Rooflights
Paul Trace from Stella Rooflight offers advice on navigating UK Building Regulations and
Planning Laws
In his address to the House of Lords in 1943, Sir Winston
Churchill emphasised the profound influence that the
built environment has on our lives, advocating for the
faithful restoration of the House of Commons following
its wartime destruction. “We shape our buildings; thereafter they shape us,” he said. His sentiment underscoring
the significance of preserving the character and identity
of historic buildings, which form an integral part of our
national heritage, evoking a sense of pride and identity
among many Brits.
Unfortunately, contemporary construction practices often
undermine this heritage by utilising inappropriate materials. The market for rooflights, in particular, frequently
showcases substandard, mass-produced, often imported
products masquerading as 'conservation' solutions. Despite their allure in terms of cost and claims of performance, these offerings do little to uphold our architectural
legacy.
Conservation Rooflights and Building Regulations
In the UK, Building Regulations mandate adherence to
specific performance and quality standards for all new
constructions, renovations, extensions and conversions.
Pertaining to the installation of rooflights these regulations
are outlined in Part L (Conservation of Fuel and Power)
of the UK Building Regulations Approved Document.
Part L requires that rooflights meet certain thermal
performance standards. This means that they must be
designed to prevent heat loss and to reduce the need for
artificial lighting during the day. For rooflights, the
relevant consideration is the thermal transmittance,
which is measured as a U-value in units of W/m²K
(Watts/meter square Kelvin). The lower the U-value the
more efficient the construction is at keeping heat flow
through the structure to a minimum. The latest regulations deem the minimum acceptable U-values to be 1.6
W(m2K).
While there may be a temptation to opt for modern
products to achieve optimal U-values, there are traditional conservation rooflight designs that comfortably
meet these standards while preserving the Victorian
aesthetic.
There is also a rather large caveat in respect of thermal
performance for conservation properties, with certain
exemptions for historic and traditional dwellings. The
Approved Document states that the energy efficiency of
historic and traditional dwellings should be improved only
if doing so will not cause long-term deterioration of the
building’s fabric or fittings.
Conservation Rooflights and Planning Permission
Before you need to worry about whether your choice of
conservation rooflight meets UK Building Regulations, it
is first important to navigate UK Planning Laws, which
safeguard a building's character and the architectural
integrity of its surroundings.
Generally, installing a rooflight falls under permitted
development, obviating the need for planning permission
if specific criteria are met. However, further considerations
arise when installing conservation rooflights in Listed
