Heritage Retrofit

BCD SPECIAL REPORT ON

HERITAGE RETROFIT

FIRST ANNUAL EDITION

has run a local energy-efficiency advice

service in the Bristol and Somerset area for

more than 20 years, including home visits

for complex cases. It is regularly called

upon to advise householders in traditional

homes on how to improve efficiency

(mainly by reducing heat loss). Three

things are becoming increasingly clear to

CSE advisers as they deliver these services:

• Residents of traditional homes

often have little knowledge of the

construction techniques used in

them, or the way in which moisture

moves through the building. This is

compounded by a tendency to believe

(perhaps because of the marketing

techniques of modern housebuilders)

that moisture movement in or through

walls should be resisted at all costs,

and that it is a sign of an underlying

problem with the house.

• Very few people understand the

meaning of the term ‘significance’

when applied to historic properties.

Householders typically fail to

distinguish between impacts on

historic significance and impacts on

the physical fabric of the building

when proposing change. They are

not the same; one can be present

without the other – for example poorly

fitted insulation which increases

condensation could lead to physical

damage in the first instance by creating

a build-up of damp between a stone

wall and internal wood panelling. If

the wood panelling then has to be

removed as a result, then not only is

there physical damage but ultimately

loss of historic significance as well.

However, it is also possible to damage

only the historic significance of a

building, for example by obscuring

decorative brickwork with external

wall insulation where this measure has

no detrimental effect on the physical

fabric of the building. Conservation

officers may well object to proposed

retrofit simply because it will damage

historic significance, a concept that

the householder often finds vague and

elusive, without causing actual physical

harm to the building.

• It is very common for householders

to want to make changes based on

a desire for a particular product or

measure (such as double glazing),

rather than a desire to see a particular

outcome (such as reducing draughts),

often because they have received some

sort of marketing literature about the

product in question.

Particularly where buildings are listed

or in a conservation area, these three

factors are the source of a great deal of

conflict with local authority conservation

and planning teams who expect greater

justification for the installation of

potentially damaging measures than

many householders are prepared to give.

More guidance is also becoming available

to support local authorities in framing

their decisions. The forthcoming Historic

England conservation research report The

Sustainable Use of Energy in Traditional

Dwellings (authored by CSE, expected

Spring 2017) is targeted at local authority

planning and conservation officers and

explores how to use legislation and policy

to guide decision-making.

Where the building is neither listed

nor in a conservation area, there is no

such oversight from local authority

experts, and these three factors (alone

or in combination) mean that many

householders are making changes to their

properties that can be hugely damaging to

their value, both from a heritage point of

view and also in physical terms.

To try to cut through some of this

potential for conflict, the Centre for

Sustainable Energy produced a booklet

titled

Love Your Old Home

in 2014. The

booklet guides homeowners through a

four-step process to evaluate what makes

their home historically significant, and

what that means for the types of energy

efficiency improvements they could make.

CSE is also working with the National

Trust on guidance for applying for and

securing consent for traditional home

retrofit, which is primarily aimed at

helping residents in protected buildings to

understand how to apply for consent for

appropriate measures, but will also be a

useful resource for local authority officers.

An accompanying online resource is also

being developed to provide technical

advice on a range of retrofit measures

THE ENERGY HIERARCHY

The energy hierarchy is an excellent

framework for thinking through the range

of possible changes:

• first reduce energy demand (for example

by changing behaviour in the home)

• then ensure energy is used as

efficiently as possible

The Centre for Sustainable Energy’s

Love Your Old

Home

booklet (2014)

Damp and mould caused by poor external wall

insulation (Photo: Centre for Sustainable Energy)

LEAST INVASIVE

INVASIVE

MOST INVASIVE

WALLS

Gap filling

Internal solid wall

insulation

External solid wall

insulation

Insulating within depth of

timber frame

ROOFS

Loft hatch insulation

Rafter insulation

(heated loft)

Loft insulation

(unheated loft)

Flat roof insulation

FLOORS

Gap filling and floor

coverings

Under-floor insulation

(suspended floor)

Under-floor insulation

(solid floor)

Under-floor heating

Over-floor insulation

WINDOWS

Thermal curtains and blinds

Refurbishing or reinstating

shutters

Refurbishing and

draught-proofing

original windows

Replacing non-original or

badly damaged original

windows with timber

double glazing or slim-line

timber double glazing

Film secondary glazing

Framed secondary glazing

DOORS

Door draught-proofing

New high-performance

thermal doors

Door refurbishment

Creating a draught lobby

CHIMNEYS

Chimney blocking