Agenda item

Report of the Planning & Development Director.

The Sub-Committee considered a report of the Planning and Development Director concerning repairs and minor alterations to the existing windows and window framing at first, second and third floor levels of Crescent House, including: stripping, repairing and redecorating existing window frames; replacement of existing single-glazing with vacuum glazing panels; insulation works to the main concrete vaulted roof and first floor concrete soffit; and associated works.

 

The Town Clerk referred to those papers set out within the main agenda pack as well as the Officer presentation slides and an addendum that had been separately circulated and published. She stated that Item 4 – Full Application for Crescent House, Golden Lane Estate, London, EC1Y 0SL and Item 5 – Application for Associated Listed Building Consent would be considered together.

 

Officers presented the application, highlighting that the application site was on the edge of the Golden Lane Estate. The buildings of the estate were Grade II listed and Crecent House was Grade II* listed.  It was both part of the Barbican and Golden Lane Conservation Area and was itself a registered park and garden.

 

Members were shown the principal west elevation of the building up and down Goswell Road and were informed that it was regarded as a seminal work of architecture by Chamberlin, Powell and Bon with the significance of the buildings assessed at full in Paragraphs 70 to 82 of the report.

 

Members were shown an image of the east elevation facing into the Golden Lane Estate, a general arrangement plan showing Members how the flats were arranged around a central corridor running through the building and west, east, north and south elevations of the building.

 

Members were shown a photograph of the window arrangement, taken after installation in 1962 and a photograph of the condition of the window today showing the minimal amount of change apart from ad hoc works. The condition of the windows today had prompted this application and the pilot project that preceded it.

 

The Officer informed Members that the proposals had four main elements: - 1) the repair of the window frames; 2) the replacement of the glass with vacuum insulated glass; 3) the installation of insulation; and 4) additional ventilation. The Officer stated that last year, consent was granted for a pilot project at 347 Crescent House.

 

Members were shown photographs taken before and after the works. Members were informed that the pilot project had indicated that there would be around a 50% reduction in both in energy demand and in external noise transmission. The window frames would be stripped and assessed and then repaired to varying degrees, depending on the extent of defects.

 

Members were shown images of the new module of vacuum insulated glass. The Officer stated that this was a sensitive addition that would look largely similar to the existing single glazing.

 

Members were shown images of the existing condition and proposed condition of the main timber windows, vertical pivot windows and jalousie windows. The Officer stated that slightly more work was proposed to the jalousie windows, replacing the existing windows with a new panel of glazing that would be fixed in position to prevent excessive air and heat leakage.

 

In relation to insulation, Members were shown images of how the existing inbuilt bookshelf would be lined with aerogel insulation and insulation would be applied to the main barrel-vaulted roof, the kitchen windows and to the ground floor soffit of the arcade. This would alter the profile of the kitchen windows and the appearance of the soffit of the arcade.

 

Members were informed that ventilation was proposed to be amended with a demand-controlled ventilation system relying mainly on a new fan in the bathroom and a new trickle vent discreetly located in the window frame. Members were shown images of these proposals.

 

The Officer stated that the proposal amounted to quite minor work to the listed building, albeit across the extent of the building to all flats. Members were shown the comparatively minimal external appearance of the flats within the pilot project. The Officer stated that the proposed work would also deliver substantive, thermal and environmental benefits, and was therefore recommended for approval.

 

The Chairman explained that there were two registered objectors to address the meeting and he invited the objectors to speak. In addition, Deputy King would address the meeting in support of the objectors.

 

Mr Philippe Rogueda, stated that he was a resident and leaseholder in Crescent House. He stated that other residents of Crescent House were also in attendance. Mr Rogueda thanked Officers for a second opportunity to work together to find the best solutions regarding Crescent House. He stated that he supported the work to date on the windows and stated that the work was first proposed 22 years ago. He stated the residents’ request in 2022 to repair and not replace the windows was supported and instead, vacuum glazing had been incorporated into the proposal. He informed Members that the residents were attending in the same spirit of co-operation. He raised concerns that the current application was for substantial work which would lead to major disruptions to residents lives, with residents having to leave their properties and remove their belongings for a minimum of three months, with some residents becoming homeless. He stated that the works would be costly to the leaseholders in excess of £100,000 per flat which was about 25% of the current market value of the flats.

 

Mr Rogueda stated that the duration of the project was planned to be in excess of six years. He informed the Sub-Committee that he was objecting to the planning application not because he did not want the repairs and new glazing to proceed, but because he was requesting conditions be added.

 

Mr Rogueda stated that no decision should be taken before the pilot project was completed. He informed Members that the planned repairs to the oriel windows had not been completed and testing of the ventilation had not been carried out. He added that the original internal beading of windows had been destroyed and replaced and the kitchen roof had not been repaired. Also, a series of tests critical to inform the current application and specifically requested by Mr Edwards would only be taking place in the following week. He stated that this project was not finished and the current application should therefore not proceed.

 

In relation to the frames and frame elements, Mr Rogueda stated that these must be retained as much as possible. He stated that there were deviations from that commitment on the windows of Flat 347 and that he had observed that the beading of the kitchen windows had been removed and the jalousie windows had been destroyed. He stated that in relation to the aluminium windows, there was no need to treat them or replace them.

 

Mr Graham Kern, resident of Crescent House and secure tenant stated that there had been a requirement for FINEO vacuum glazing to be tested on the pilot flat before glazing was chosen. He stated that Officers had advised that this could not be fitted in the round windows of the flats on the third floor. He also stated that the first and second floor windows did not have round windows nor toughened glass and therefore FINEO could be used. He stated that the third-floor flats could have a mix of FINEO and LandVac.

 

Mr Kern stated that all of the third-floor residents with jalousie windows in their bathrooms opposed to having them removed as proposed as this would make the flats more damp and also hotter in the summer. He stated that this would lead to legal infringement when the windows were removed, as this would be a breach of the grant of the lease of the leaseholders. Mr Kern stated that although the proposal claimed that the fenestration and subdivision and operation of fenestration would not change, it was proposed to remove the jalousie windows. He added that there was also a heritage issue with the windows an essential part of the design of the flats on the third floor, and they were integral to the grade two star listing, which must be respected. He stated that it was claimed that these windows were responsible for 18% of the heat losses from each flat but this was unproven.

 

Mr Kern stated that the current ventilation proposal was best removed at this stage or otherwise should be much better explained and tested before implementation. Also, as the ventilation would require drilling holes in concrete which would be highly disruptive, it should be optional in leasehold flats.

 

In relation to insulation, Mr Kern stated that aerogel and Rockwool were proposed for the soffit insulation. He stated that Rockwool was much thicker than aerogel and would lead to significant changes to the appearance and aesthetic of the building. He added that aerogel was proposed for the parade of shops to protect the heritage and requested that aerogel be used for the whole soffit as proposed by the conservation area consultee.

 

Mr Kern stated that although it was proposed to replace the roof insulation, there was no evidence that the roof insulation was faulty. He added that insulation over the kitchen flat roofs was required and that this work was meant to be carried out during the pilot project but had not yet been started.

 

Mr Kern stated that no repairs were proposed to the oriel windows to avoid water dripping onto the façade, eroding the facade and future water damage. He requested that a design proposal be included to protect the oriel windows and stated that work was also meant to take place during the pilot project but had not been done.

 

Deputy King informed the Sub-Committee that after general discussions with residents, she considered there were technical issues that could possibly be addressed via conditions. She thanked the applicants for all their hard work on this important project on a Grade II* listed building that welcomed many visitors to the City of London. She also thanked them for engaging with and listening to the residents who not only had intimate knowledge of how the building performed, but had also brought their time, money and professional expertise to this project. She stated that the only reason vacuum glazing was now the accepted approach was as a result of the research undertaken by the residents.

 

Deputy King raised residents’ concerns about the refurbished aluminium frame and stated that the finish was not good and detracted from the overall success, the window had no thermal break and would be a condensation source and need wiping down not to damage the timber surround. It had not yet been thermally tested. She advised that research on a window with a thermal break had been undertaken and asked that the installation and additional testing during the rest of the winter months be included as part of the conditions. She also raised concerns that the metal frame would transmit sound and acoustics should be considered. Deputy King suggested that the remaining pilot period should be used install a replacement window with a thermal break and improved acoustic performance if acceptable to residents and heritage organisations and achievable at a reasonable cost, and the results should then be compared.

 

Deputy King raised concern that the current ventilation proposal had not been tested in actual living conditions i.e. with curtains and with bathing and cooking taking place and this testing should be undertaken. Condition 14 referred to 12 months of tracking the performances of the flats, but any problems would have to be addressed retrospectively, at which point at least half the residents would have gone through the upheaval of decanting. She requested that this be de-risked as much as possible before the work started with tests carried out over the next few months with the flat occupied to verify the system.

 

Deputy King stated that some leaseholders wanted to keep their jalousie/louvre windows which was an issue only for the top floor. She understood this could negate the ventilation system as proposed and asked if there were any options for a window that opened in the bathrooms or the retention of the original windows.

Further concerns were raised about the roof and soffit of the oriel window not having insulation which was a floor 1 and top floor issue. Deputy King stated that the shedding of water was a current problem that did not seem to have been addressed and asked if it was possible to review the design of the roof and soffit to have a more holistic approach to prevent the damage recurring.

 

She requested that Members also on Community and Children’s Services Committee and the Finance Committee push for as generous a payment system as possible to assist residents with the bills arising from this innovative and important project by the City of London Corporation.

The Chairman asked if Members of the Sub-Committee had any questions of the objectors.

 

A Member asked if the extra conditions or comments made by Deputy King would be taken into account. Deputy King stated she hoped the issues raised would be addressed.

 

The Chairman invited the supporters of the scheme and the applicant, to speak.

Ms Gaby Robertshaw stated that she had lived in Crescent House since last year, and that Crescent House, along with the whole of the Golden Lane Estate, had a creative community.

 

Ms Robertshaw stated that the proposal would see the leaseholders asked for life changing sums of money. She informed Members that over 50% of all residents taking part in the consultation questionnaire and over half of the residents, tenants and leaseholders had lived there for over 10 years. This project had brought neighbours together, residents had pooled their talents and meetings were arranged. The 60th anniversary had been marked with open house tours inside and out. Residents’ points had been taken into account in relation to the pilot flat application. Ms Robertshaw stated that the proposed project would be the largest residential restoration project in Europe to use vacuum double glazing.

 

Ms Robertshaw stated that almost five years ago, the Corporation had undertaken concrete repairs to Crescent House. She commented that the report stated that the Corporation intended to carry out investigations into specialist cleaning for the façade. She stated that stripes on the concrete meant it was essential not to delay the cleaning and requested that concrete cleaning be conditioned. She stated it had been 20 years since any major maintenance took place and residents had waited more than 10 years for the windows project to come to fruition. Ms Robertshaw stated that Crescent House was in the heart of the culture mile and was a gateway building into the City of London, as such the project required a linked approach. She added that the application resolved many of the problems.

 

Mr Jason Hayes, Senior Surveyor, Community and Children’s Services Department, on behalf of the applicant, stated that the proposals in the application aimed to achieve a balance between following the listed building management guidelines to retain and respect the historic fabric of the building and make sensitive performance upgrades to the windows.

 

Mr Hayes informed Members that this project started first and foremost as a windows project and some of the changes had been the result of resident engagement. Listening to ideas and suggestions from residents of part of regular resident group meetings and positive engagement events over time, the project scope was expanded to include other works to improve the fabric of the building to help move towards a low carbon future and provide affordable social housing for Crescent House.

 

Members were informed that the pilot project in Flat 347 had given all stakeholders a valuable opportunity to assess the works proposed to the windows and this had been beneficial to the consideration of the application. It had enabled the support of Historic England and 20th Century Society to be secured. It had been demonstrated through testing and calculation that the proposals had significant impact on reducing heat loss and heating demand, improving air tightness and reducing the intrusion of the external noise. It had also allowed the continuation of the engagement with residents on the proposals.

 

The Sub-Committee were informed that the residents, tenants and leaseholders, both residents and non-residents of Crescent House had all been invited to view the completed project and the views were wide ranging, diverse and very welcome. Overall, there was general support for the works, but there was concern from a number of residents over some of the detail and there were differences in views of what the balance point between conservation and performance improvements should be.

 

The objectors had questioned the choice of manufacturing vacuum insulated glass. While this was not strictly part of the application, the team’s preference of LandVac had been based on the following key points: 1) It could be manufactured to all of the sizes required to the existing window frames whereas the other options could not;, 2) it had better thermal performance than the other options; 3) every sheet of the LandVac was fabricated from toughened glass and this was an important factor in reducing likelihood of breakage; 4) the supply of LandVac glass proved quicker and 5) it had fewer micro spaces.

 

Mr Hayes advised that the proposal sought to retain as much historic fabric as possible whilst improving performance. In the pilot project, the aluminium frame was removed, dismantled, cleaned, and re-anodised to protect the metal from further decay. As the metal was pock-marked, tarnished and weathered, the anodised finish would vary in appearance. The frame was reassembled with the vacuum glass incorporated along with the new rubber gasket. The new glass would improve the overall thermal performance of the window and would help to manage some of the condensation risk. However, it was not thermally broken. He added that the only way to achieve a full thermal break would be to install a new window frame. BRE testing had demonstrated that only 5% of the air leakage from the home was through this frame. As part of the pilot project works the team would continue to investigate new thermally broken aluminium frames, so the heritage impacts and performance improvements to this alternative approach could be assessed.

 

Mr Hayes stated that the louvre window had been removed in the pilot project and the main application proposal. The BRE testing had demonstrated up to 20% of all the air leakage from the home was through this window when it was closed. The format of the window made it almost impossible to improve the airtightness or the overall thermal performance of the window. The team acknowledged that removing the louvre window would impact on the listed fabric, but to retain it would undermine the positive impacts and performance of the ventilation solution being applied. A ventilation solution was applied to manage humidity within the properties because condensation, damp and mould were major issues within the block and these required managing. 

 

Members were informed that once completed, there would be ongoing cyclical maintenance inspection of the refurbished windows. Working with the specialists and contractors, the team would develop a maintenance plan and schedule. It would cover, in detail, when inspections and subsequent actions would be required to maintain the windows, including the finish and also components such as ironmongery and seals. Inspections work would be proactive and identify further repairs and would also include planning for access to the facade.

 

The Chairman asked Members if they had any questions of the supporter and applicant.

 

A Member asked if the suggestions made by Deputy King could be incorporated into conditions. The applicant stated that the team would look to complete investigations into the aluminium window. In addition, the water deflection of the oriel roof would be included within the main application. Although it had not yet been done within the pilot project, this would help deflect the water away from the main post in the bay window.

 

The Chairman asked for clarification as to whether all the conditions and variations raised by the objectors had been considered by the applicant in their evaluation before putting forward the application. The applicant stated that he understood the majority of the issues had been addressed in the report.

 

The applicant was asked if more could be learnt by monitoring the effectiveness of the project for longer. The applicant stated that monitoring the project and the performance of the improvements e.g., heat loss and noise transmission was required by condition for the 12 months from completion of the project. Environmental sensors could be used to sense humidity and temperature and prove that the improvements were working. The pilot project gave a unique learning experience and allowed performance to be tested and monitored. If it was possible, someone would live in the property for the next few months, which would be the coldest time of the year to show the results on heat retention and ventilation.

 

A Member asked, if as an objector had stated, the programme would take 6 years and whether any delay to the programme would lead to significant deterioration in the frames, particularly the ones to be treated at the end of the programme. The applicant stated that the programme was still to be formalised with the contractor once the works had been tendered. Having contractors on site with the necessary skills would mean if any ad hoc repairs were required to the existing façade, these could be undertaken. It was likely that the windows in the worst condition would be repaired first. The maintenance regime would start once the works to the first flat had been completed. It was important to have the right competencies and skills in place for work to such a significant heritage building.

 

In response to questions about the length of the programme and how long residents would be out of their flats, the applicant stated that the time residents would be out of their flats would be dependent on the condition of the windows and the amount of work that was required. A more recent condition survey completed by a Royal Institute of Chartered Surveyors (RICs) surveyor, had provided an indication of the works required, however once the works began, more work could be found. It was important to communicate with residents throughout the work. Currently it was expected most residents would need to decant from their property for 4-5 weeks. The programme length would depend on the amount of skilled labour available for a heritage project such as this and also properties available within the community to use for decanting residents. Although it was intended to keep residents on the estate, void properties were not common.

 

In response to a question about the cost to each leaseholder, the Chairman stated that cost was not a material planning consideration.

 

In response to a Member’s question about the oriel window and whether louvre windows could be optional, the applicant stated that investigation was taking place into the oriel windows. Regarding the louvre windows, the ventilation had to work with an airtight window but consideration would be given to whether an openable window could be installed. Air tightness would not be achieved with a louvre window as even when closed there was 20% air leakage from the home.

 

In response to a question about whether the system had been tested with a fan in another area, in order to save the louvres which were an integral part of the architecture, the applicant stated that the point that air was extracted varied from flat to flat and was largely determined by where the existing ducts that ran through Crescent House were located. In some homes it was pulling air from the bathroom, in others it was pulling air from the kitchen and in other homes, it was pulling air from both the kitchen and the bathroom. Wherever air was being pulled from, the louvre windows created a short circuit in the system as it was the easiest location for the intake of air.  There was a concern that if the louvre was situated at the back of the property, that the ventilation system, even if it was pulling air from the kitchen, would not be pulling air efficiently from the living and bedroom spaces and the air circulation would short circuit around the back of the flat. It was only by maintaining a relatively continuous air tightness in the kitchen and the bathroom that the system would be pulling air from the front facade of the building.

 

The Chairman suggested that the Sub-Committee now move to any questions that they might have of Officers at this stage.

 

A Member raised concern about the use of the word ‘opaque’ in Condition 4 in relation to the glazing under the bookcase, and asked if it could also state that it should be glazed to match the existing glass in terms of performance.  An Officer confirmed that the wording could be changed from ‘opaque’ to ‘translucent’.

 

A Member welcomed the review of street lighting. She stated that street lights which were an integral parts of the façade did not work currently and some residents did not want them on as they were outside their windows. She requested that if renovated, and repaired so they could work, they were not switched on. An Officer stated that this would be covered as part of the lighting strategy required by this condition. It would be dealt with if and when that condition came forward.

In relation to the aluminium window and oriel window, a Member asked if these could be included under Condition 7 or Condition 8 as issues to be considered under relevant details. An Officer stated that these proposed amendments could not be made as this would be a material change to the scheme that was not part of the existing scheme and this would therefore require a consultation.

 

A Member requested that Condition 14 be amended to require that test results of the ventilation system during the occupation of the pilot project flat be received before ventilation works commenced. The Officer stated that this was embedded in Condition 14.

 

A Member referred to conditions suggested by Deputy King in an email and asked Officers if they had seen and considered these. An Officer stated that he had seen the email and informed Members of his response to the points raised. He stated that the aluminium pivot window was an original existing window and Officers considered that its retention and refurbishment was a conservation optimal outcome and that there might be variation in the finish of the said window but that was typical of these kinds of schemes and that full replacement of it for the listed building would not be as beneficial. The Officer stated that in terms of the thermal break or the thermal performance of the window, it could not be conditioned that the window be replaced as this was not part of the scheme. This would require a re-consultation as it would be a material change to the proposals.

 

In relation to acoustic performance, the Officer stated that the initial test that had been undertaken as part of the pilot project had indicated around a 50% reduction in noise transmission. In terms of using the remaining pilot period to install a replacement window, the Officer stated that the physical works of the pilot had been completed. As outlined, it was not possible to condition and require the replacement of the aluminium window.  The Officer stated that Condition 5 as amended in the addendum however, would allow for the replacement of the aluminium windows with details to be submitted if the windows are unable to be repaired.

 

In relation to ventilation and louvre windows, Officers considered that Condition 14 as recommended was suitable and allowed for appropriate post occupancy evaluation of the flats with people living in them so that a wider spectrum of information could be obtained to inform the rest of the project. The Officer stated that the retention of those jalousie and louvre windows would undermine the holistic approach to improve the thermal performance of the building envelope and could compromise the ventilation strategy that had been advanced. The demand-controlled hydroscopic ventilation system would pull the damp air through and out of the flat. If the louvre window was retained, it would create a point of weakness. Officers considered that the measures in place were appropriate both in respect of energy efficiency and ventilation performance, but also in respect to the listed building.

 

The Officer stated that in respect to the oriel windows, there were new sills proposed to the windows which were larger and protruded further to shed the water away from the facade. New lead flashing was also proposed to the window heads below the oriel roof to shed water away from the facade.

 

The Officer stated that insulation to the roof had been explored but it was deemed unsuitable for this quite prominent principle location due to the heritage impacts that could occur and the visual impact.

 

A Member had queried the Energy Performance Certificate (EPC) rating with the applicant and had been advised in one case it would go from an E to a D rating following the works and in another case, it would go from a D to a C rating. He requested that Officers follow up with the government as a lot of expensive positive work was taking place and there were concerns about the rating system if all this work only resulted in a D rating.  He considered that this was an excellent opportunity concerning how much work was being done to use this as a case to the government to get the EPC calculation corrected. Officers stated that they were in discussions with the government on the EPC regime and they would raise this issue.

 

A Member referenced the balancing act of the listed building conservation elements of the scheme and ensuring original details were retained against these being homes and it being important they were warm and mould-free. She asked for confirmation that environmental health officers would be monitoring work to ensure that if issues arose, they could be rectified quickly.  An Officer stated that Conditions 13 and 14 set out the required maintenance strategy and also the testing of the three pilot flats over the first year of their occupation would cover the points raised. The monitoring would allow for an understanding of any defects that might be caused by the new works and deal with them appropriately.

 

A Member asked if a proof of concept could be conditioned as if for any reason, the work did not result in improvements, there could be significant costs associated with retrofitting. An Officer raised concern that this would be a pre-commencement condition and would be exceptionally onerous to implement. He added that Officers considered that the testing that had already taken place and the rigorous conditions that were in place were sufficient to understand post completion results. The Officer clarified that Officers were not aware of any of the issues raised e.g. water ingress, being an issue in the pilot.

 

Seeing no further questions, the Chairman asked that Members now move to debate the application.

 

A Member stated that he had asked a number of technical questions of the applicants and had been impressed with their responses. He considered this to be an excellent scheme. He stated that when this was discussed last year, the applicants were requested to address ventilation along with insulation and air tightness and they had done this. He did not agree with a suggestion that ventilation holes be optional as this would create issues with damp and mould. He commended the applicant on the proposal to retain as much of the frames as possible.

 

A Member commented that this was a good scheme, there were numerous constraints with the Grade II * listed building here and he considered anything that caused further delay to be undesirable. He stated that he was in favour of the careful monitoring of the first flats to be converted, so that if any problems arose, these could be addressed and harm to the whole scheme would be limited. He considered this scheme to be the best possible outcome.

 

A Member stated that the material that residents had found in terms of the FINEO window glass had made a real difference to the scheme. Officers had listened to the technical expertise of the residents. The Member expressed disappointment about the aluminium window and the possibility that another application might have to be made. She stated that if this was the case and a sample was made and approved, this should be progressed quickly to avoid any further delays to the work.

 

A Member stated that her initial preference was for the replacement of all the windows and she still had concerns about repairing windows that had been in existence for so long, but she was happy to support this application. She stated that the applicant had taken into account the concerns of residents and this work would transform these homes.

 

A Member thanked the residents for bearing with the project for so long, and Officers for listening to and working with the residents. She stated that this dialogue with residents should be continued, working with residents to resolve any issues quickly.

 

Having fully debated the application, the Committee proceeded to vote on the recommendation before them.

 

Votes were cast as follows: IN FAVOUR – 14 votes

                                            OPPOSED – None

                                            There were no abstentions.

 

The recommendation was therefore carried unanimously.

 

RESOLVED –

That Planning Permission be granted for the above proposal in accordance with the details set out in the schedule attached to the Officer report.