a.aa MMC M11 52pp Web

External Building Envelope
THE FUTURE
OF URBAN
DEVELOPMENT
IS LOOKING UP
Estimates vary on how many homes could be created in UK cities by extending buildings vertically. Recent studies
suggest that there may be space for as many as 20,000 to 40,000 new rooftop dwellings in the centre of London alone.
Furthermore, The National Planning Policy
Framework (NPPF), as of July 2018,
includes specific reference to in support of
upward living. The document states that planning
decisions should support the use of the ‘airspace’
above buildings especially if “the development
would be consistent with the prevailing height
and form of neighbouring properties and the
overall street scene”.
The availability of land, particularly in cities, is a
significant challenge to meeting the current
demand for housing. Roof Top Developments
(RTD) negate this issue by utilising the existing
building with no need to find new land and enable
the creation of additional storeys without
increasing the overall footprint of the building. The
added value of this approach is that, unlike the
majority of greenfield developments, it allows
much needed housing to be created in the areas
of cities where land is most scarce. Furthermore,
the planning permission process is often much
simpler as the transport infrastructure and
amenities are already in place.
One of the most effective ways of achieving
upward extensions to buildings is through the use
of modular and panelised building solutions.
These RTD systems consist of a lightweight,
robust steel frame construction, which can be
built into panels off-site, craned into position and
assembled. The external cladding, insulation and
finish can then be applied, and the new flats
connected to the building’s services. The
properties can then be fitted out in the same way
as a traditional build.
This innovative approach by Langley enables the
building to benefit from any number of additional
storeys providing planning permission can be
secured, the existing building has enough
structural capacity and the layout allows sufficient
access for residents. In some cases, a structural
frame can be used to support the additional
storey. This is added to the outside of the building
and concealed with cladding to maintain the
aesthetic of the building.
In addition to utilising the existing roof space,
vertical development using modern methods of
construction also has a number of specific
benefits over building on green- or brownfield
sites. As there are no costs for the ground works
that would be required for a new or in-fill
development, homes can be created at a much
lower cost per unit. This cost effectiveness is
particularly valuable for social housing providers
and local authorities where making best use of
often limited capital is vital.
Additionally, panelised RTDs provide an increase
speed within the construction process, reducing
time on site. The work can often be carried out
while the building is still occupied, further
minimising the disruption for current residents.
Despite the benefits of extending upwards, one of
the barriers to widespread adoption is acceptance
by building owners and leaseholders. Here there
is scope for local authorities, housing associations
and the build to rent sector to lead the way in
normalising the approach. These organisations
can, and in some cases, are already, engaging
with their tenants to explain the intended work
and formulate a plan that will deliver tangible
benefits to existing residents. Adding a further
storey delivers best value when planned as part
of a wider regeneration of the property. Once a
template for development has been created the
process can be replicated across a number of
buildings to maximise the use of land in an area.
Roof Top Developments offer a quick, simple and
cost-effective way of creating additional dwellings,
supporting existing communities in towns and
cities. While small scale vertical extension of
private homes is not a new concept, the largescale
developments that will help address the
issues with housing demand in cities has not yet
achieved widespread adoption. Despite this,
recent changes in government policy and
forward-thinking organisations embracing the
concept have helped begin this process and give
developers confidence in the model.
www.langleystructures.co.uk
38 Feb 2019 M11