Church of St. John the Baptist, Corby Replacement Roof Covering to South Aisle Heritage Impact Assessment
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CHURCH OF ST. JOHN THE BAPTIST, CORBY REPLACEMENT ROOF COVERING TO SOUTH AISLE HERITAGE IMPACT ASSESSMENT Heritage Impact Assessment 1.0 INTRODUCTION St. John the Baptist Church has suffered water ingress through its roof for a number of years but this has worsened recently and a lasting solution to solve this problem needs to be found so that the fabric and contents of the building can be preserved into the future for the enjoyment of many generations to come. This document has been prepared to support the proposal that the lead sheet covering to the south aisle be replaced by terne coated stainless steel with batten rolls. 2.0 SITE PARTICULARS Corby was a small rural town north of Kettering which was hugely expanded as a new town in the 1960s, providing housing for the steelworks, creating a new town which now surrounds the old town. The church is located not far from the new shopping centre (1960s) surrounded by residential properties, with a roundabout at its south east corner pretty much onto the highway, with a waist high wall separating the high wall from the churchyard, which has a number of trees partially screening the church from the road. To the north are lime trees and the church hall and a grassed area public space. The building is Grade II* Listed and it is in the Corby Village Conservation Area. The church itself dates back to the twelfth century but most of the fabric is thirteenth and fourteenth century and it comprises a nave, north and south aisles, a west tower and spire and south porch with a north vestry. The nave, chancel and south aisle are lead covered, the other parts of the building having various roof coverings, including terne coated stainless steel to the north aisle, re-covered (following theft) in 2017. The roof leaks are predominantly to the lead nave and south aisle roofs. 3.0 NEED FOR REPLACEMENT There have been leaks for some years but these have worsened recently and it has become apparent that lead repairs are needed on a regular basis and that, consequently, the south aisle roof in particular has reached the end of its effective life and needs to be replaced. Not repairing the roof would have negative consequences which would include: - Damage to the significance of the building. - Damage to the significance of the contents of the building. - Making the building unusable. - Loss of an important cultural asset for the community. - Loss of an important community facility in this part of Corby. The lead sheets have worn over time and have become thinner and the lead batten rolls split and the lead fails at other locations where it has been bent tightly into sharp angles. 4.0 SIGNIFICANCE OF BUILDING AND ITS ROOF COVERING St. John's Church as a whole is of Exceptional Significance, being one of only 21,768 Grade II* Listed buildings in England and one of 368 in Northamptonshire, a county renowned for its 'squires and spires'. The building as a whole achieves this Listing and in many ways it is the ensemble of the building's fabric and its site and setting which combine to deserve this grading at the heart of the community, whose once rural setting has been encroached upon by the new town and its roads close to the churchyard. Replacement Roof Covering to South Aisle 1 Church of St. John the Baptist, Corby Heritage Impact Assessment The significance in terms of Architectural, Aesthetic and Artistic values is Exceptional, as is its Archaeological and Evidential significance. Its Historic and Communal significance is probably of Some significance, being locally important and, likewise, its Setting and Landscape significance is only of Some local significance. The entire building is Listed, albeit some constituent parts may have less significance than others. Arguably the most significant parts of the building are its masonry carving/stonework, its stained glass, its monuments, headstone and tombs, its fixtures and fittings and other contents, and these constituent parts are all highly valued, these values being categorized differently as Evidential, Historical, Aesthetic, Communal, Architectural and Cultural. The key issue is how detrimental and harmful the proposed intervention and change will be to the significance and values of these features. We acknowledge the significance of the lead sheet roof material and its removal should not be carried out lightly. If the proposal were to dramatically change the visual appearance of the roof covering and if it were more obviously on view we agree the case for its replacement with something new would be less easy to justify. Any harm caused by the proposed change in the roofing material will be very minimal. 5.0 ROOF COVERING OPTIONS The current roofing materials under consideration for the leaking roofs to the nave and both aisles are: 1 Replace lead sheet with new lead sheet: Concern regarding vulnerability to theft, which is proven by the theft of the north aisle roof covering in 2016. A roof alarm was installed in 2018 to try to mitigate the possibility of further theft. 2 Terne coated stainless steel (TCSS) with batten roll joints similar to traditional lead: Requires Planning Permission/agreement from Local Authority and hence this application. Is more noisy that lead during rainfall. 3 Copper: Standing seams are inappropriate in this historical setting and it is a more obvious visual change than TCSS, being a different colour. 4 Zinc: Standing seams are inappropriate in this historical setting and it is a more obvious visual change than TCSS, being a different colour. 5 Slate: Roof pitches are too shallow. 6 Plain tile: Pitches are too shallow. 7 Single ply membrane: Inappropriate vapour impermeable solution can cause sweating of roof timber and consequent decay. Replacement Roof Covering to South Aisle 2 Church of St. John the Baptist, Corby Heritage Impact Assessment 8 Concrete tile: Too heavy for the current roof structure, which would need to be strengthened, and would impact negatively on the significance, and in any case would be too shallow for the current roof pitch. 6.0 POLICY AND PLANNING AUTHORITY 6.1 We have been advised by Corby Borough Council that a Non Material Amendment Planning Application is required. The view of the Local Planning Authority’s Case Officer was expressed in their Brian Hawkins’ e-mail of 5th August 2020: “With regards to your enquiry regarding the replacement of the lead covered roof to the church, I fully understand the need to expedite the situation to avoid internal damage to the historic fabric of the Grade II* building, however I think it is necessary to submit a formal application, which following discussions with the senior planning officer could be within a Non Material Amendment application, which could result in a much speedier and simpler application, in terms of detailing and timescales. I am sure you understand and appreciate the importance of not only the internal fabric of the building itself, but also of the due process of the planning system and protection of our listed and ecclesiastical buildings.” As a practising place of worship the church is exempt from Listed Building Consent. Historic England are also being consulted simultaneously and their response will be copied to CBC on receipt. The south aisle roof covering cannot be seen from anywhere at ground level - either in the churchyard or further afield. We argue that, consequently, any change to the roof covering in an appropriate material would be 'de minimis' and that therefore Planning Permission, in whatever form it takes, should not reasonably be withheld by CBC. 6.2 The National Planning Policy Framework 2019 clause 189 states: In determining applications, local planning authorities should require an applicant to describe the significance of any heritage assets affected, including any contribution made by their setting. The level of detail should be proportionate to the assets’ importance and no more than is sufficient to understand the potential impact of the proposal on their significance. As a minimum the relevant historic environment record should have been consulted and the heritage assets assessed using appropriate expertise where necessary. Where a site on which development is proposed includes, or has the potential to include, heritage assets with archaeological interest, local planning authorities should require developers to submit an appropriate desk-based assessment and, where necessary, a field evaluation. 6.3 NPPF Clause 196 requires applicants to demonstrate that where proposed harm will occur to the significance of a heritage asset, the harm is outweighed by the benefit to the community of the proposed works. We argue that the benefit to the community of having a fit-for-purpose communal building with a new watertight roof not being vulnerable to theft outweighs the small degree of harm of which there is very limited visibility of parts of the roof covering from selected viewpoints. Replacement Roof Covering to South Aisle 3 Church of St. John the Baptist, Corby Heritage Impact Assessment 6.4 We have identified the building to be of Exceptional significance, as its Grade II* Listing confirms, and note that less than substantial harm will be done to the heritage by the proposed change of roofing material from lead sheet to TCSS, which will not be visible from ground level. 7.0 JUSTIFICATION FOR TERNE COATED STEEL 7.1 The existing lead sheet roofs are past their economic lifespans and need to be replaced if damage to the historic fabric and its contents is to be avoided. The defects can be summarized as follows: - Lead sheets have eroded and have become very thin and are hence susceptible to thermal movement causing splitting, evidenced by many lead burn repairs.