Sustainability Draft Supplementary Planning Document

Technical Guidance

Insulation

Listed Building Consent is not normally required unless original building elements would require temporary removal.

Insulating suspended timber floors from below is usually preferable except where there is a historically significant surface to a ceiling below. Installation from above should only be considered where it is not possible to insulate from below.

If installation from above is required, a professional will be required to avoid damaging historic building elements (e.g. floorboards, skirting boards, door architraves).

Quilt or rigid board insulation is preferable – sprayed foams will not usually be acceptable as they are not easily reversible should future repairs be required.

Breathable materials should be used to maintain the passage of air and moisture.

If lifting floorboards reveals 'deafening' material, this should be left in place, as it can be an efficient fire retardant.

Airtightness

Listed Building Consent is not normally required, unless the appearance of the room would be significantly affected.

Draughtproofing Skirting Boards, Ceilings and Flues

Any mastic-type draught proofing should be as discreet as possible in colour (i.e. clear, or matching the surrounding colour as closely as possible)

Skirting boards: Care should be taken if temporary removal of skirting boards is required.

Flues: temporarily sealing of unused flues is also a simple process that does not require consent – chimney balloons are simple to fit and are removable. Typically, they also permit some air flow through being ill-fitting, which is important for ventilation. Total sealing of flues is not recommended.

Draughtproofing Floors and Doors

Floors: Sealing the gaps between floorboards, traditionally referred to as caulking, is the most likely of these measures to affect appearance and can make them harder to lift in the future. If you are planning any associated works that may require lifting of floorboards these should be done before sealing these gaps. Proprietary flexible caulking strip is an inexpensive and simple measure for draught proofing the gaps between timber floorboards. It should be noted that comprehensive eradication of natural ventilation beneath timber floors can lead to damp and decay.

Unobtrusive products should always be used and loss of historic fabric avoided.

Non-permanent solutions should be favoured where possible (e.g. laying a rug or another breathable membrane on the floor).

Professional installation will be needed for products such as rebated edge seals

Care should be taken to ensure the strength of the frame is not compromised. This is particularly the case with slender late 18th century sash windows where the timber sections are often very narrow.

Secondary Glazing

Listed Building Consent is not normally required for secondary glazing.

Ensure that the design is as discreet as possible and does not obscure distinctive architectural detailing, including careful alignment of any glazing bars and use of slim frames of appropriate colour. With terraced dwellings, the design should retain a sense of unity with surrounding properties.

Ensure that they will not compromise the use of existing shutters

Minimise the impact of permanent fixings required to secure the new frame

Consider fitting secondary glazing within an easily removable frame that does not require a separate subframe and will allow the use of the existing windows and, where they exist, shutters.

The secondary glazing units can be colour-finished to match the existing interior decorative scheme.

In many circumstances magnetic strip secondary glazing is likely to be consented.

Further Guidance

• Historic England (HE) Advice Note 16 : Listed building consent
• HE: Advice Note 14 - Energy Efficiency and Traditional Homes
• HE: Energy Efficiency and Historic Buildings: How to Improve Energy Efficiency
• The Sustainable Traditional Buildings Alliance (STBA) Responsible Retrofit Guidance Wheel
• HE: Energy Efficiency and Historic Buildings Secondary Glazing for Windows
• HE Traditional Windows - Their Care, Repair and Upgrading
• HE I Want to Alter My Windows
• HE Modifying Historic Windows as Part of Retrofitting Energy-Saving Measures

On-site Low Carbon and Renewable Energy

Standards

Technical Guidance

Solar Photovoltaic and Solar Thermal

Listed Building Consent is required for PV roof slates and solar panels on listed buildings and any buildings within their curtilage (built before 1948).

Guidelines for Heritage Assets:

• Panels should be located so that they are not overtly visible in short and medium distance views and in longer distance views blend, through product type into the roofscape. This can be achieved by:
• Avoiding prominent and highly visible roof slopes of primary elevations
• Considering roof slope of rear, secondary elevations
• Considering inner roof slope of double pitched, M style roof
• Avoiding reflective materials and match the colour of the existing roof covering
• Where ground mounting can be accommodated consider the setting of heritage assets, character and appearance of the conservation area and potential of below ground archaeology
• Considering that evacuated tube solar thermal systems are more visible than flat-plate panels. (However, they require less space, and can be well suited to flat roofs)

Panels located on listed buildings should:

• Avoid harm to historic fabric
• Consider the implications of the additional loading (consult a structural engineer)
• Avoid significant alteration to a roof structure
• Carefully consider the location and the impact of associated infrastructure on historic fabric and internal appearance

Further Guidance:

• HE: Energy Efficiency and Historic Buildings: Solar Electric (Photovoltaics)
• Energy Saving Trust: A comprehensive guide to solar panels

Heat Pumps

Listed Building Consent is required where it involves alterations to the listed building.

Ground Source Heat Pumps

Boreholes need to have regard to the County of Avon Act (1982) which protects the source of the Bath hot springs (contact the Council for more detailed advice)

Older properties often contain microbore pipework, which may need to be replaced as it is not usually compatible with a heat pump. Care should be taken when planning pipe runs.

When used for space heating, heat pumps work most efficiently with under-floor heating. This is unlikely to be appropriate under undisturbed, historic floor surfaces. However, where this is not the case, such as where there is a poor quality modern, replacement flooring, the installation of under floor heating may be possible. In which case it is recommended that limecrete is used which can be used in conjunction with insulation and under floor heating systems whilst allowing the transfer of moisture.

Care should be taken when drilling boreholes adjacent to any particularly fragile structure to avoid damage.

Further Guidance:

• Energy saving rust: A guide to ground source heat pumps
• Centre for Sustainable Energy (cse.org.uk): Ground source heat pumps
• HE: Installing Heat Pumps in Historic Buildings

Air Source Heat Pumps

Listed Building Consent is required for an air source heat pump.

Buildings of a traditional construction require a level of passive natural ventilation and the design of the heat pump system will need to allow for the lower levels of insulation and higher rate of ventilation.

Care should be taken to locate the external unit of an air source heat pump in a discreet location away from the principal elevation – this could include behind greenery or fencing. You can also find ducted ASHP units which can be located indoors.

If under-floor heating is not possible, radiators may be considered. In some cases, historic radiators may survive and are likely to be considered as significant elements of the interior and therefore their retention is important. Where this is not the case, new radiators should be of a discreet design and sensitively-located.

Older properties often contain microbore pipework, which may need to be carefully replaced as it is not usually compatible with a heat pump.

When used for space heating, heat pumps work most efficiently with under-floor heating. This is unlikely to be appropriate where there are significant historic floor surfaces which could be harmed from being lifted. However, where there is not the case, such as where there is already modern, replacement flooring, under floor heating may be possible. In which case, it is highly recommended that limecrete is used which can be used in conjunction with insulation and under floor heating systems whilst allowing the transfer of moisture

Further Guidance:

• HE: Installing Heat Pumps in Historic Buildings
• Centre for Sustainable Energy: Air source heat pumps

Electric Vehicle Charging Points

Listed building consent is required if the charging point is attached to historic fabric.

Choose a discreet location for any associated equipment

Be mindful of the setting of heritage assets and the requirement to preserve or enhance the character and appearance of the conservation area

Avoid physically altering a heritage asset where possible and, where this is unavoidable, minimise the damage and loss of historic fabric.

Consult the Council's pre-application/planning advice service at the earliest opportunity to seek specialist advice.

Water Efficiency:

Listed buildings or buildings in conservation areas are not exempt from complying with building regulations. However, the special needs of historic buildings are recognised in some of the building regulations' approved documents. Approved Document G addresses sanitation, hot water safety and water efficiency and includes the following pertaining to historic buildings:

'Special considerations may apply if the building on which the work is to be carried out has special historic or architectural value, and compliance with the sanitation or hot water safety requirements would unacceptably alter the character or appearance of the building or part of it.

'When undertaking work on or in connection with buildings with special historic or architectural value, the aim should be to improve sanitation and hot water safety where and to the extent that it is possible provided that the work does not prejudice the character of the host building or increase the risk of long-term deterioration to the building's fabric or fittings.

'In arriving at a balance between historic building conservation and sanitation or hot water safety requirements, it would be appropriate to take into account the advice of the local authority's conservation officer before work begins.'

Rainwater Harvesting

Listed Building Consent is required for rainwater harvesting systems and support will be given to sensitively detailed schemes. The alternative DIY rainwater harvesting option of simply using water butts or buckets to collect and recycle water does not require listed building consent.

Further Guidance:

• UK Rainwater Management Association (ukrma.org)

Greywater systems

Listed building Consent is required for grey water harvesting systems in listed buildings.

Further Guidance:

• Greywater for domestic users: an information guide (sswm.info)

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