The Crescent House Pilot Project is currently under way in Flat 347 Crescent House. The aim of the project is to explore, review and refine proposals for works in residents’ homes and demonstrate to all those involved and potentially impacted by the works the extents, quality and effectiveness of what is planned.

The specific aims of the Pilot Project are to:

Establish a detailed understanding of the condition of the original timber window frames.

Define a method for assessing the extents of timber repair and replacement.

Trial the installation of different vacuum glazing systems.

Conclude a design to effectively mechanically ventilate the home.

Understand any possible impacts on the gas central heating system.

Inform the construction and logistics plan for the overall works.

Measure the performance improvement delivered by the work (thermal, acoustic, air tightness, weather tightness).

Establish a benchmark for the expected quality of works.


Preliminary work

Following the erection of the external scaffold, a detailed survey was completed and extensive testing was undertaken on the existing windows. The survey had to be undertaken to identify the presence of any asbestos or lead paint and the asbestos found had to be removed from site before any work could be started.

Then a number of Planning Conditions had to be discharged prior to any work starting on the window refurbishment which included a full photographic survey of the existing windows followed by a detailed architectural survey, both of which had to be submitted to the Planners for approval. A detailed method statement for the works also had to be submitted for approval by the Planners along with a scheme of protective works.

Following the submittal of the surveys, a series of tests were undertaken on the existing windows, these included acoustic, air tightness, thermographic and water tightness testing. These were to provide a base line case to compare the performance of the newly installed windows against.

Removal of existing glass

The first work that was undertaken was to remove the existing glass to measure and template it to be able to order new vacuum glazing. We hope to trial two types of vacuum glazing and assess their relative benefits in terms of cost, performance, availability, lead-in times etc. The next stage of work was to remove the existing beads from the timber frames to enable the glass to be removed to be measured and templated to provide the glass sizes to place the order for the new vacuum glazing panels. There are two suppliers of vacuum glazing one is based in China, Landvac and the other in Belgium, Fineo.

The aim is to trial the two types of vacuum glazing and assess their relative benefits in terms of cost, performance, availability, lead-in times etc. While Landvac are able to manufacture the required sizes of glazing, Fineo are unable to manufacture the larger panes and there will be a need to make minor alterations to the frames and beads to accommodate their glazing. The two products have minor variations with the Landvac having a small circular port in the bottom corner of the pane to remove the air in manufacture and both types having different configurations of small dots within the panes to keep the two pieces of glass separated. There are samples of both types of glass in Flat 347.


Assessment of the condition of the window frames

Once the beads and glass had been removed from the frames the paint was removed from the timberwork and it was rubbed down at which point a detailed assessment of the condition of the timber could be undertaken. Establishing the condition of the timber enabled the team to determine a method for repairing the frames, repairing smaller areas with resin filler and repairing larger areas by cutting in new timber sections or replacing sections of timber where necessary.

There is one window in Flat 347 that is a side hung aluminium window. This was removed and sent away to a factory in West Sussex to be dismantled and refurbished. When the vacuum glazing is delivered to site the glass for this window will be sent down to Sussex to be installed within the refurbished frame in the factory. Once installed the window will be returned to site and fitted in to the timber window framework.

With the paint removed and timber rubbed down in Flat 347 it became clear that there was a considerable amount of rotten timber that previously had not been apparent on the opening pivot window in the bay area. These areas were cut out and repaired with resin and by cutting in new sections of timber.

In Flat 347 the original window handles have been lost and work is progressing to use an original one as a template to produce further handles.


 Repair work is progressing to all the frames.

There have been a number of meetings on site to agree the specification of the opaque glass to be installed in the bay window area and to agree the details of the insulation to be installed at the back of the bookshelf.

There has also been a considerable amount of time spent reviewing the size of beads to hold the glazing once installed.

Repair work

With the glass on order, further repair work was undertaken and the design details reviewed with regard to the bookshelf insulation and the composite panel details to be installed under the windows in the bay areas. To maximise the available area of bookshelf a thin insulated blanket (spacetherm) has been specified and this will also be used in the composite panel in the bay.

Arrival of the glass

The Landvac glass recently arrived at Felixstowe and once through customs is due to be delivered to site week commencing 14th August. It is then anticipated that the glass installation, composite panels and bookshelf work will be completed Mid -September. After this work has been completed a further period of testing on the windows will be undertaken. This will again include acoustic, air tightness, water tightness and thermographic testing to enable a comparison to be made to the original window installation.

It is anticipated that the Fineo glazing will be delivered week commencing 4th September. On site there are samples of both the Fineo and Landvac glass along with the glass for the opaque composite panel and spacetherm insulation. There is also a question about the finish to be applied to the timber with different clear finishes to be applied as samples for review. Once the window work has been completed further testing will be undertaken and the test results will be compared to the results from the original window installation.


Along with establishing a benchmark for the expected quality of the window refurbishment work, the Pilot Project aims to provide a design to effectively mechanically ventilate the flats and to determine any possible impacts the installation may have on the gas central heating system.

The ventilation system design has been established which includes new fans and a trickle vent to be installed on an external window. On visual review of this vent it was thought that it would be better to box it in and a design for this has been progressed and this will be installed as part of the window installation.

With regard to an alternative heating system, work is progressing on a design for a fully electrical system with assistance from Dimplex to find an effective, economical system to install and run. A Sample of this system will be installed in the Pilot Project.

Temporary decanting of residents

There has been a lot of discussion about the logistics of undertaking the work in individual flats and there will be a need to relocate residents to temporary accommodation while the work in their flats is being carried out. It is anticipated that three flats will be renovated at a time and as a result three vacant flats will need to be provided to residents as temporary accommodation. Repair work will be undertaken to Flat 347 which will involve the installation of an accessible bathroom, a new kitchen and decoration of the flat. New furniture will also be installed to be able to re-assure residents of the quality of the temporary accommodation they will be provided with. A design and specification are due to be issued shortly and it is anticipated that this work will be part of the completed Pilot Project.

Future timetable

The Programme for completion of the Pilot Project is 16th October following which inspections will be undertaken by Historic England, 20th Century Society, Planners, Members, Residents etc. Following completion of the Project, final updated information will be issued to the Planners and there will be a further three-week Consultation Period prior to the issue of the Planning Officer Report. This report will be then issued to the Planning Committee and it is anticipated the Application will be heard at the Committee Meeting on 12th December.

You can follow the Pilot Project journey here:

September 2023 Pilot Project Update