Newly renovated Cambridge Church blessed with warmth from Selectaglaze secondary glazing

  • 5 Oct 2021

Downing Place United Reformed Church is located in Cambridge. It was formed in June 2018 following the coming together of Emmanuel and St Columba’s United Reformed Churches, which were previously situated in different locations. Selectaglaze secondary glazing now features there…

Downing Place United Reformed Church occupies the former St Columba’s building in Downing Place, constructed in 1891 in the Early English style and stands within the Historic Core Conservation Area. The restored St Columba’s site has been significantly renovated as part of a £3.3 million project led by Archangel Architects into a stunning church and community centre. 

The Church was formerly made up of three overlapping rectangles; the church and two halls in the form of a zigzag, which made the uses of space challenging to define. Although sitting prominently on a street corner, prior to the renovation access into the building was restricted.

The central hall has now been converted into a beautiful double-height community hub, along with meeting rooms on two levels. Wherever feasible, measures have been taken to make the Church more energy efficient, including the insulation of the historic fabric, photovoltaic panels, and the inclusion of secondary glazing. 

Thermal retention

The main contractor Coulson Building Group discussed secondary glazing solutions for the purpose of thermal retention with Selectaglaze. Becoming thermally efficient and wasting less energy was of paramount importance to the Church, not only on an environmental level, but also economically. Secondary glazing considerably improves insulation within existing buildings.

Selectaglaze has a number of tested products that can decrease the U-value of a window to around 1.8 when glazed with low emissivity glass. Furthermore, secondary glazing is fully accepted by Conservation Officers because it is a reversible adaptation i.e. it can be removed at a later date with almost no effect on the original fabric of the building.


Various options were evaluated during the design process. In the end, it was agreed side hung casements were to be installed in the Chapel where the primary windows were rectangular with a very gentle curve at the top.

Fixed light secondary glazing was specified for the much larger windows in the Nave, with slim framing sections and interlocks. It was unnecessary for the secondary glazing to open as natural ventilation would be acquired through the opening of newly installed roof lights. Additionally, the Church would only clean these units occasionally.  

56 units were installed; comprising of four Series 45 side hung casements in the Chapel and 52 Series 46 slimline fixed lights installed in the Nave. The slimline Series 45 hinged casement system is appropriate for treating many types of window and standard sized doors. Neat flush hinges and slim handles or flush locks provide clean internal lines.

Series 46 slimline fixed light

The Series 46 slimline fixed light can be shaped or curved to a full circle – perfect for church windows that do not need to be opened often. Little maintenance is normally required to well designed and constructed stained glass. Both the Series 45 and 46 secondary glazed units will reduce heat loss by up to 50%. High performance compression seals will practically eliminate drafts and ensure much greater comfort near the window. 

Full scaffolding was needed for the installation of the high-level units and for the survey too. To prevent an extended period of restricted access for other works, Selectaglaze worked with the contractors Coulson to devise a method of survey which could be achieved without the scaffold saving money and programme time. 

A very complex treatment involved a large circular primary window in the Nave due to its shape and elevated position. A proven method of fixing was used for this secondary glazing treatment.  Having previously worked on a similarly large circular window, a timber mullioned cartwheel frame was crafted to securely hold the secondary glazing.

The timber subframes were built in segments with each mullion split to be screwed simultaneously within the window opening during installation, forming the cartwheel frame. Seven bespoke Series 46 fixed light segments were made for it and glazed with 6mm toughened glass to give additional firmness and structural strength.  

The Church is delighted with the installation, particularly with how well the secondary units blend in seamlessly with the stone surrounds. The church has now been made more thermally efficient with the inclusion of secondary glazing and it should begin to see a reduction in heating costs, with less heat escaping and uncomfortable draughts practically eliminated. The church has become a warmer and more comfortable space.

To read about Selectaglaze installing 47 secondary glazing units to a number of large gothic arched stained-glass windows in St Philip’s Church, Wolverhampton, click here.


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