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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)