14
BCD SPECIAL REPORT ON
HERITAGE RETROFIT
FIRST ANNUAL EDITION
SUSTAINABILITY STANDARDS
& REGULATIONS
JOHN EDWARDS
T
HE MENTION of the energy
efficiency of buildings almost
always brings up U-values, energy
performance certificates, standard
assessment procedures (SAP and RdSAP)
and building regulations. Those who are
a little more informed may also refer
to terms like BREEAM, Passivhaus,
BREDEM and possibly even EnerPhit.
These are all to do with prescribed ways of
dealing with energy efficiency of buildings
and sometimes their wider sustainability.
All have their place but will not
necessarily be appropriate and reliable,
particularly where historic or traditionally
constructed buildings are concerned.
However, they are often the means by
which we have to assess such issues.
Many of the acronyms stand for things
we don’t necessarily have to adopt, but we
do have to be mindful of them because
of the potential benefits as well as the
potential risks in adopting such schemes
and processes.
One regulatory framework that
applies to almost all development is
the Building Regulations, and the part
concerning the conservation of fuel
and power is particularly important.
Although there is some variation between
those adopted by each of the UK home
nations, all versions require what we call
‘consequential improvements’ when works
to the thermal envelope are undertaken.
THE BUILDING REGULATIONS
In England and Wales, the Building
Regulations are worded more emphatically
than in Scotland and Northern Ireland.
While there is an expectation that
reasonable efforts will be made to improve
energy efficiency, listed buildings,
scheduled monuments and buildings in
conservation areas do enjoy some degree
of exemption depending on which UK
home nation they are in. However, over
90 per cent of traditional buildings don’t
come under these categories even though
from a technical perspective, most of
the buildings are just the same as those
which receive statutory protection. In
England and Wales ‘special consideration’
can be given to buildings which have
vapour permeable construction when
the regulations would otherwise require
work which may impede the movement
of moisture. In Northern Ireland and
Scotland it is less emphatic but, as
in England and Wales, work must be
‘technically feasible’ and this is where
the imposition of such works can be
challenged. Here, British Standard 7913
can be used to support the case for not
undertaking works which would adversely
affect the building’s performance.
BS 7913:
2013 Guide to the Conservation of Historic
Buildings
(to give the standard its full
name) emphasises that damp building
fabric could be over a third less thermally
efficient than dry building fabric, thus
highlighting the importance of appropriate
repair and maintenance measures as
described in the document. In this
respect, building maintenance is an energy
conservation measure that should always
come before the ‘improvements’ arising
out of the Building Regulations, RdSAP
and such like..
One very important issue that
BS 7913
raises is the need for proper condition
surveys based on an understanding of the
pathology of historic buildings and the
materials used: this is especially essential
when considering the impact of problems
such as damp. Another important issue
is the need to consider significance
and the undertaking of heritage impact
assessments. All traditional buildings
have some significance and the impact
of measures on that significance always
needs to be understood.
A miner's cottage in David Street, Cwmdare: analysis of the building's pathology as required under BS 7913:
2013 provided information on the effects of damp on the in situ U-value, and demonstrated that the walls were
more thermally efficient than predicted. (Photos: John Edwards)