Supporter's Column: Cindy Walters

A reflection about how the funding stream, Salix Finance, might benefit public sector projects.

Salix Finance: what is it and how might it benefit public sector projects?

 

By Cindy Walters (Walters and Cohen Architects)  

 

It is becoming increasingly clear to architectural practitioners that our cash-strapped public sector clients will struggle to make their aged, gas-guzzling estates and buildings more energy efficient. There are, however, various funding streams throughout the UK and across the public sector whose aim is to increase awareness about the importance of energy efficiency and decarbonisation.

One of these funding streams, Salix Finance, is the delivery body for the government’s Public Sector Decarbonisation Scheme. More than £409 million is being awarded to local authorities to better insulate and retrofit hospitals, schools, museums, universities and other public sector buildings across England in line with the government’s commitment to becoming net zero by 2050.

Two of our projects demonstrate how Salix Finance can benefit public sector projects:

St Olave’s Grammar School

The school in Orpington, Kent, was designed by Robert Matthew, Johnson-Marshall & Partners (RMJM) and constructed in 1966-1967. Classrooms wrap around quadrangles and the estate includes two houses for the headteacher and caretaker; the former is now used as an administration space. The original school building was one of a new tranche of post-war schools to be awarded Grade II listing by Historic England in 2017 as a ‘creative and ambitious example of progressive post-war secondary school design’.

Working with Max Fordham we have undertaken the first stage of applying for Salix Finance to support a site-wide decarbonisation, aiming to reduce energy requirements and replace use of fossil fuels with electricity. Heating is the main source of carbon emissions for most buildings, so meter readings and heat loss calculations have been used to analyse the impact of fabric and glazing improvements. Air source heat pumps and PVs are also proposed. Any interventions are likely to require planning consent and listed building consent, so have also been considered from a heritage and planning perspective.

Pembroke College, Oxford

Founded in 1624 by King James I, Pembroke College is about to celebrate its 400-year anniversary and invited Walters & Cohen to undertake a strategic view with the aim to make Pembroke the best College in which to study, work and live in Oxford. Guidance from the Master was that no stone should go unturned in looking at how to make improvements, underpinned by all aspects of sustainability on the basis that mitigating the scale of climate change and biodiversity loss is one of, if not the most pressing challenge of this decade. Max Fordham prepared a strategy to address these concerns, and our masterplan report proposes actions that Pembroke College should take to:

 

1. Understand their major environmental impacts in detail

2. Mitigate and communicate their actions in relation to those impacts

3. Further develop and optimise their strategy

 

One of the most innovative elements of our strategy is secondary glazing for a stained-glass window in the dining hall. We explored options to develop a suitable window system using different combinations of glazing types, framing materials and fixings to find the right solution.

Research took us down several dead ends: materials were rejected for not being supportive enough of this large expanse – 4m high by 2.5m wide – until a combination of timber and steel was selected for the frame. Modelling identified how the frame could be located within the chamfered stone to mirror the geometry of the lines. This proved challenging; while vacuum glazing seemed viable, it could not be cut to the required shape and tolerances for the bespoke curved elements.

To overcome this, we considered vacuum glazing for the rectangular panels and a standard secondary glazing solution for the upper curved panels. Adopting a ‘hybrid’ solution would require both glazing types to be consistent in depth (8mm) so the frame can support them. It was also important to consider airflow to minimise condensation and the ability to remove glazing for occasional cleaning of the stained-glass panels.

3D surveys revealed that each window has different volumes and heights, introducing greater complexity. To solve this, timber is used to frame the reveals, designed to hold the steel frame and be more accurately shaped to the existing windows. The preferred design is being constructed as a prototype to demonstrate the visual performance and impact, and we’re excited to see the outcome.

 

This article was written by Cindy Walters, of Walters & Cohen.