Heritage and sustainability issues in conservation areas

This note does not apply to listed buildings.

Policy CP15 in City Plan Part 1 states that: “Where proposals are promoted for their contribution to mitigating climate change, the public benefit of this will be weighed against any harm which may be caused to the significance of the heritage asset or its setting”.

The supporting text goes on to say that: “Where proposals that are promoted for their contribution to climate change objectives have a potentially negative effect on a heritage asset, the council will wherever possible help the applicant to identify feasible solutions that deliver similar climate change objectives but with less or no harm to the heritage asset and its setting”.

You can find policy guidance in Supplementary Planning Document SPD09 ‘Architectural Features’ (pp 28 to 34).

For houses in conservation areas, you can find practical guidance and more information on energy efficiency in Planning Advice Note PAN 09 ‘Householder guidance on energy efficiency for historic houses in Conservation Areas’ (pp 10 to 13).

Energy efficiency in repaired, replaced and new windows will be encouraged. Existing historic windows contain embodied energy and unless beyond economic repair it is more sustainable overall to retain and upgrade them.

Draught-proofing and secondary glazing offer ways of reducing heat loss without involving high costs or needing planning permission.

Another option is to install low-emission (Low-E glass) into existing sashes or casements.

In many cases sound historic windows can also accommodate slimline double-glazing fitted into the existing sashes or casements and again this would not require permission. 

Double glazed windows will generally be permitted, but on elevations that face onto a street or public open space the original windows’ material, style, pattern and joinery sections must be matched.

This may often mean using slimline double glazing (12 to 14mm). Double glazing will not normally be appropriate to replace original multi-paned sash windows that have fine joinery.

On rear elevations UPVC windows can be supported provided they:

• retain the original sash arrangement
• respect the uniformity of the elevation’s fenestration
• are not clearly visible from a street or public open space

It should be noted that the framing material, whether UPVC or timber, makes little difference to the U-value (rate of heat loss) of a window as the heat is mainly lost through the glass.

Inspectors in appeal decisions have consistently supported the council’s policy approach on replacement windows.

Find guidance on the requirements for planning permission.

Policy guidance can be found in SPD09 ‘Architectural Features’ with regard to external walls and materials and details, such as render, mouldings, brickwork and flintwork and so on.

Specific practical guidance and further information can be found in Planning Advice Note PAN08 ‘External Wall Insulation’.

In conservation areas, planning permission is required for external wall insulation and the following heritage considerations will apply:

• on front walls in conservation areas EWI is unlikely to be acceptable because of the impact on the façade and streetscape
• EWI may be acceptable on side and rear walls of properties in conservation areas not visible from the highway or public open space, depending on the design and material of the building and subject to detailing - in this case a hybrid wall insulation system can be considered - for example, a combination of internal and external wall insulation
• EWI is unlikely to be acceptable even on rear elevations where there is architectural detailing such as corbels under eaves and windows, or other decorative mouldings or architectural detailing - the covering over of stone or good quality original fair-faced brickwork, flintwork and mathematical tiling is also unlikely to be acceptable

You can find practical guidance and further information on solar technologies in PAN 09 ‘Householder guidance on energy efficiency for historic houses in Conservation Areas’ (pp 25 to 26).

In most cases on unlisted buildings in conservation areas, roof-mounted solar panels are permitted development (PD) under either Part 14 Class A or Class J of the General Permitted Development Order (GPDO) 2015 (as amended), subject to certain criteria and conditions.

However, in the following conservation areas permission will always be required for solar panels on dwelling houses under the terms of an Article 4 Direction:

• Ovingdean
• Patcham
• Portslade Old Village
• Rottingdean

In these areas roofs are particularly important to the character and appearance of the area and may be viewed from higher ground or surrounding downland as well as from streets and open spaces.

Siting of panels will therefore need to be carefully considered where proposed.

Where permitted development rights apply, one of the conditions is that solar PV or solar thermal equipment must, so far as practicable, be sited so as to minimise its effect on the external appearance of the building and the amenity of the area.

In considering this we will take into account the:

• public visibility of the roof slope/area – could the panels be sited on a hidden or less prominent part of the roof and still be functional, taking into account orientation?
• position and shape of the PV array – a neat rectangle of panels set centrally in a roof slope will be less intrusive than an irregular-shaped or jagged-edged array or an array that appears sited haphazardly

Solar panels should be avoided on front gable roofs wherever possible as these would have a more noticeable impact on the street scene.

If the panels are to be sited on a prominent roof slope, consider whether they are matt or glossy. A matt appearance will be less intrusive. Solar slates can be a more sympathetic option.

Find more guidance on whether you need planning permission for solar panels.

You can find practical guidance and more information on air source heat pumps in PAN 09 ‘Householder guidance on energy efficiency for historic houses in Conservation Areas’ (p 28).

On unlisted domestic buildings in conservation areas the installation of an air source heat pump within the curtilage is permitted development under Part 14 Class G of the GPDO, subject to certain criteria, but is not permitted development if it would be installed:

• on a wall or a roof which fronts a highway or
• so that it is nearer to any highway which bounds the curtilage than the part of the dwelling-house or block of flats which is nearest to that highway

In all cases the equipment must, so far as practicable, be sited so as to minimise its effect on the external appearance of the building and on the amenity of the area.

There are no permitted development rights for air source heat pumps on nondomestic properties. SPD09 ‘Architectural Features’ (p 48) discourages additions such as meter boxes on visible street elevations and ASHPs are much larger, so the same principle would apply, but any harm would need to be balanced against the sustainability benefits as per Policy CP15 of City Plan Part One.

Where permission is required, an ASHP would be acceptable in heritage terms where the property has a large front garden and/or the equipment would not be visually intrusive when seen from the public realm.

Where visible it may be necessary for it to be suitably screened (for example, with planting).

An ASHP is unlikely to be acceptable in the case of terraced properties with small front gardens where the equipment would be prominent from the public highway, but there may be potential to site one in a basement lightwell, for example.

On unlisted buildings in conservation areas, the installation of a ground source heat pump within the property’s curtilage is permitted development under either Part 14 Class C or Class L of the GPDO.

The installation of an electrical outlet for recharging electric vehicles is permitted development under either Part 2 Class D (wall mounted) or Class E (on an upstand), subject to certain criteria, which include that it must not be installed within 2 metres of the highway and if on a wall must not face the highway (see Class D and Class E for full wording on restrictions).

However, such an installation may be dependent on the demolition or part-demolition of a front boundary wall or railing to enable access or parking.

In such cases the policy guidance on front boundaries set out in SPD09 ‘Architectural Features’ (pp 42 to 45) will apply, which does not permit the loss of front boundaries to enable car parking.

While the installation of an electric charging point provides a sustainability benefit, planning appeal decisions have found that this in itself would not be enough to outweigh the great weight afforded to the conservation of heritage assets (See BH2019/02236, 56 Surrenden Road; BH2020/02754 1 Pembroke Crescent; and BH2021/00916 20 Bavant Road).

The council has a programme of installing on-street electric vehicle charging points, which includes provision for residents to request one near where they live.

Find out more about electric vehicles and charging. 

Cycle storage structures in front gardens will always require permission.

Supplementary Planning Document SPD12 ‘Design Guide for Extensions and Alterations’ notes that “the front elevation and other parts of the property visible from the street are normally more sensitive to change than other parts of the property that are not visible”.

SPD09 ‘Architectural Features’ notes that “alterations are frequently proposed to historic buildings in order to adapt them for modern living requirements, to improve access or in the interests of energy efficiency.

These may appear minor in nature but can, if undertaken without care, harm the appearance of the building and its significance. The cumulative effect of such minor alterations can be particularly damaging.

Wherever possible such alterations should be confined to concealed elevations and sited and fixed in such a way that causes the minimum possible impact upon the building.

Standard solutions are not always appropriate to historic buildings and it may be necessary to investigate alternative approaches or products in order to minimise any impact”.

Cycle storage structures in front gardens should therefore be carefully sited so as to minimise their visual impact from the street and to ensure no harmful impact on neighbours’ amenity.

The scale of the cycle store should be shown to be the minimum necessary to achieve its function and should not be out of scale with the house or garden.

A cycle store should not be set in front of a bay window and should not obscure any important architectural features of the house or terrace.

Where properties have larger front gardens, they are better able to accommodate cycle stories without impacting on the street scene. In terraced streets with smaller gardens it may be possible to partially screen a cycle store behind a front boundary wall/railings or to set it against a side boundary wall to minimise its visibility.

Where small front gardens are raised above street level a cycle store can be visually intrusive and unless it can be sufficiently screened it will be unlikely to be acceptable in these cases.

In all cases the cycle store should be designed attractively in appropriate and durable materials and wherever possible should be screened by landscape planting.

Communal cycle storage

The council is rolling out a programme of installing on-road cycle hangars for residents to park their bikes securely near their homes where they don’t currently have space.

The cycle hangars are the size of approximately one parking space and can store 6 standard sized bicycles.

Find out more about cycle hangars.

Where on-road cycle hangars are available nearby this may be a material consideration in determining an application for an individual domestic store, particularly where harmful impact has been identified.

Historic buildings and energy efficiency

Retaining historic buildings in use is inherently sustainable as it avoids the consumption of building materials and energy and the generation of waste from the construction of replacement buildings. It is however acknowledged that historic buildings may be less energy efficient than new buildings.

Where energy efficiency proposals would have a potentially harmful impact on an historic building the council will wherever possible help the owner or occupier to identify feasible solutions that deliver greater energy efficiency but with less or no harm to the historic building or its setting. Such improvements should avoid the loss of historic fabric and features and should be reversible.

In considering improvements for energy conservation it is important to remember that buildings of traditional construction perform very differently to modern buildings. The fabric of a traditional building needs to ‘breathe’, so that moisture within walls etc. (from rising damp, driving rain or condensation for example) can be released through evaporation. Modern impermeable building products can obstruct this process and lead to moisture being trapped inside, causing damage to the building. This can be worsened where ventilation has been reduced.

The council has produced planning guidance on retrofitting issues for houses in conservation areas as well as separate technical guidance specifically on external wall insulation. Please see PAN09 for Householder guidance on energy efficiency and PAN08 on External wall insulation.

Planning permission may be required for energy efficiency improvements and you should always check with the Planning service. If your property is a listed building then Listed Building Consent will be required for most energy efficiency works, including internal works such as internal wall insulation.

Find more guidance on how we apply policy on heritage and sustainability issues.

Saving energy

Historic England (formerly English Heritage) provides useful advice and publications on a range of energy efficiency measures.

Energy Saving Measures will likely affect the fabric of historic buildings.  The council’s policy on works that affect historic fabric, such as replacement windows, can be found in SPD09 Architectural Features.  Historic England also provide advice on works to windows in historic buildings.

Energy Performance Certificates (EPCs)

An Energy Performance Certificate (EPC) is not required in respect of listed buildings or historic buildings in designated conservation areas where “compliance with minimum energy performance requirements would unacceptably alter their character or appearance”. Government guidance on this can be found in respect of dwellings here https://www.gov.uk/government/publications/energy-performance-certificates-for-the-construction-sale-and-let-of-dwellings and in respect of non-dwellings can be found here https://www.gov.uk/government/publications/energy-performance-certificates-for-the-construction-sale-and-let-of-non-dwellings--2 The guidance provides examples of the types of works that are likely to be considered unacceptable.

Whist this guidance states that an EPC is not required if it would result in unacceptable alterations, it may be the case that it is necessary to get an EPC in order to find out whether ‘unacceptable’ works are in fact required. The guidance provides typical examples of likely unacceptable works but we would be happy to advise on the likely acceptability of any specific works that an EPC may require to a particular property. Please note that if a historic building is not listed but is within a conservation area internal alterations to improve energy efficiency can be carried out without the need for any planning approval.

Other sources of guidance and information

There are a number of other sources of information and guidance on energy conservation in historic buildings available on the internet:

The council’s General Housing Team provides information on a number of energy saving measures, sources of information and funding avenues.

The Sustainable Traditional Buildings Alliance provides guidance on retrofit measures relating to walls, roofs, floors, windows, doors and chimneys.  Their interactive guidance wheel allows the user to customise the context and select thermal upgrading measures.  This then shows various issues and possible risks to consider before installing such measures.

Other useful sources of information from other parts of the country are Warmer Bath [1.7mb] by the Bath Preservation Trust and the Centre for Sustainable Energy and guidance documents from the City of Westminster.