Can I Put Rooflights in my Listed Building?
- Ailsa Bailey
- 1 day ago
- 6 min read
Our team at Blue Willow Heritage can provide expert advice regarding constraints and opportunities for altering your listed building. With the rise of loft conversions, ventilation standards, demands for adequate provisions of light, and escape windows in homes of the present day, rooflights are becoming increasingly commonplace within listed buildings. But how easy is it to get Listed Building Consent for these units when the proposed development site is a nationally designated historic building?
Listed Building Consent for Rooflights
Householders will need to apply for Listed Building Consent to insert rooflights into their homes if they live in a listed building. This application is required to be accompanied by a Heritage Statement, or Heritage Impact Assessment (HIA). Such statements are also often required if you live in a conservation area, even if your building is not subject to listed building protection. This is because the area in which your home is situated is still designated, instead of the physical structure itself.
Paragraph 200 of the National Planning Policy Framework (NPPF 2023) requires that applicants provide a statement of heritage significance for the building, in addition to any designated heritage assets in the vicinity likely to be affected by a development proposal. This includes nearby listed buildings and conservation areas which will have direct views of the proposed rooflights. The level of detail in this statement is only required to be proportionate to the significance of the building, in addition to the scope of the proposed changes. For example, a proposal limited to the insertion of rooflights alone would not necessarily require a detailed discussion of the significance of the planform of the structure, or an extensive description of the contribution made by individual historic architectural details present internally. In this case, descriptions of the structure's significance would primarily be concerned with an assessment of any historic fabric present within the roof structure, in addition to its external architectural form, and wider setting.
What is the Current Guidance on Rooflights?
Historic England, in their guidance on Making Changes to Heritage Assets, acknowledge that rooflights have the potential to impact upon a building's significance. However, this harm may be avoided if they are situated on less prominent roof slopes, including those on the rear elevation. Harm may also be avoided if they are placed in areas which will not impact upon any historic fabric, such as within modern roof structures where the historic building has been reroofed. Rooflights are also generally preferred to dormers in utilitarian buildings. The relevant sections of this guidance has been reproduced below:
The insertion of new elements such as doors and windows, (including dormers and roof lights to bring roof spaces into more intensive use) is quite likely to adversely affect the building’s significance. Harm might be avoided if roof lights are located on less prominent roof slopes. New elements may be more acceptable if account is taken of the character of the building, the roofline and significant fabric. Roof lights may be more appropriate in agricultural and industrial buildings than dormers. In some circumstances the unbroken line of a roof may be an important contributor to its significance.
Historic England 2016
Where rooflights are to be added it is often better to locate them on the least prominent roof-slope when viewed from a public vantage point. It is always preferable to use the flush ‘conservation type’ roof lights as these have less impact on the roof surface, particularly if non-reflective glass is used.
Historic England on the Adaptive Reuse of Agricultural Buildings, 2017
Specific guidance has also been provided by the Society for the Protection of Ancient Buildings (SPAB) who are a Statutory Consultee on Listed Building Consent applications:
The addition of new dormers and rooflights to an historic roof must be approached carefully. The existing historic roof structure should not be damaged in order to facilitate a either option and is likely to only be acceptable where they are least visible and do not compromise the special interest of the building. It is important to consider the impact of new dormers and rooflights on historic terraces: should proposals for either disrupt the symmetry design, it is likely they would harm the special architectural interest of the group.
SPAB 2024
Do I Need to Comply with the Building Regulations?
Existing residential dwellings are not automatically required to be brought up to current standards outlined within the Building Regulations. However, existing structures are expected to comply with these requirements in specific circumstances, including when they are subject to a change of use, an extension, upon the installation of controlled fittings, and the renovation or replacement of thermal elements. Listed buildings are not included in the list of structures exempt from complying with the Building Regulations under Regulation 9. However, the 'special needs' of historic buildings are recognised within some of the approved documents, which have been outlined in guidance by Historic England. It can generally be summarised that, where major safety concerns are not at stake, certain regulations can adopt a degree of flexibility for listed buildings. Those sections most relevant to rooflights have been outlined below, although it is worth noting that these regulations do not specifically outline any requirements for adequate provisions of natural light.
Rooflights as a Fire Escape: Document B
'...Particularly buildings of special architectural or historic interest for which the guidance in this document might prove too restrictive, some variation of the provisions in this document may be appropriate. In such cases, it is appropriate to assess the hazard and risk in the particular case and consider a range of fire safety features in that context.'
(Volume 1, page 3 paragraph 0.10 and Volume 2, page 4 paragraph 0.17)
Thermal Performance: Document L
‘If it is not reasonable to meet the target U-values in Table C1, considering technical risk and practicality of the work in relation to the dwelling and impacts on adjoining buildings, then the U-value should be as close to the target value as practically possible.’
(Appendix C paragraph C2)
Ventilation: Document F
'Work to a building in paragraph 0.5 should comply with the ventilation standards in this approved document where reasonably practicable. The work should not result in either of the following outcomes: a. Unacceptably affect the significance of the listed building, conservation area or scheduled monument. b. Increase the risk of long-term deterioration of the building fabric or fittings. New extensions to historic and traditional dwellings should comply with all ventilation standards in this approved document unless there is a need to match the external appearance or character of the extension to that of the host building.'
(Volume 1, page 2, and Volume 2, page 2)
What Style of Rooflights are Acceptable?
Listed Buildings require what is commonly referred to as 'conservation rooflights'. This term refers to units which do not project beyond the existing roof plane, and often make use of non-reflective glass. It is worth noting that just because a supplier advertises their product as 'conservation style' does not necessarily imply that they meet the requirements of true conservation rooflights. Many units advertised as such actually project beyond the existing roofline and therefore are, in many cases, not compliant with the expectations of local councils. Officers at your local council may request that you remove unsympathetic rooflights and replace them with more appropriate alternatives. This includes circumstances in which the necessary consents have not been obtained, or where the units installed do not correspond to the approved plans or conditions associated with the application. Any rooflights which have been inserted without permission will require a Retrospective Listed Building Consent application.
Some councils advise that, when it comes to domestic dwellings, the positioning of rooflights should respect and relate to the existing windows below. However, for agricultural buildings, there is often a preference for the existing fenestrations to be more irregularly spaced. Glazed pantiles also provide a suitable alternative for provisions of light into agricultural buildings which respect the typical character of historic utilitarian roofscapes. The number of proposed rooflights should also be limited and only installed where necessary. Again, they should be predominantly limited to the rear elevations or less-prominent facades. The specifications for acceptable rooflights may vary from region to region, and it is therefore important that you consult the published guidance by your local council. For example, general design principles for rooflights have been outlined in the Residential Design Guide produced by North Yorkshire Council.
Need some advice on whether it is appropriate to insert rooflights into your Listed Building? Blue Willow Heritage are able to provide expert advice to suit your needs, ranging from design consultations to formalised Heritage Scoping Assessments to assess the viability of your proposed development from a heritage perspective. Our team can also prepare a Heritage Impact Assessment to accompany your Listed Building Consent application. Contact us below for some no obligation advice to get your project underway!
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