William Ellis Secondary School

Over a three year programme, SWA worked simultaneously with adjacent secondary schools, William Ellis and Parliament Hill, to implement a phased, creative renewal programme to revitalise and modernise established teaching spaces.

The brief for William Ellis School was developed from specific issues that the school identified and focused on the health & wellbeing of users, with an ambition to improve the environmental performance of the school and provide opportunities for outdoor learning, whilst also updating classrooms to better suit modern teaching methods and larger class sizes.

William Ellis School is located on the edge of Hampstead Heath in the Dartmouth Park Conservation Area and we worked closely with the local planning authority to ensure that the sustainability requirements of the project were met in tandem with the conservation requirements set out by Camden. Working around the school timetable, logistical constraints and a tight budget, SWA delivered a cohesive retrofit which satisfies both the councils needs and also the schools.

Client: LB Camden / William Ellis School
Completion: 2020
Cost: £1.5 million 
Location: Highgate, London


I have not only found SWA to be consistently diligent and timely with their work but enjoyed the energy and fresh thinking they have always brought. I have never found them to be difficult or aloof, but always keen to discuss the intricacies of any project detail, and very thorough in their consultations with stakeholders. As is often the case with education projects, I have worked with SWA under very tight restrictions, both in terms of time and budgets. They have never let me down when I needed a swift response or an innovative and cost-effective solution to a problem. I can honestly say their performance has been first class throughout.”

Tim Rushforth, Project Manager, on behalf of LB Camden

Plan diagram highlighting the extent of SWA’s work at neighbouring William Ellis School and Parliament Hill School
Simplify & Unify

Originally built in the 1930’s, the school has been added to and altered ad-hoc over the last 80 years. An over-arching design ethos was to simplify the existing ‘patchwork’ school building, both aesthetically and spatially. Areas for refurbishment and reconfiguration were carefully selected to maximise and diversify spaces for learning. The works undertaken by SWA were split over multiple phases and construction contracts, often overlapping on site.

Various ‘before’ photos of the issued identified by the school

The scope included the following interventions:

1. Replacement windows and doors throughout to improve thermal comfort/control and ventilation, simplify maintenance and unify the school’s appearance

2. Upgrading external walkways

3. Classroom re-organisation and renewal where existing classrooms were no longer fit for use and in disrepair. Three scales of teaching space are provided: flexible, multi-use hub for specific departments, large classrooms for increased class sizes and smaller breakout spaces for different teaching and learning styles.

4. Demolition of a poor-quality infill building to reinstate an an original internal courtyard with new ramped access, providing accessible, external breakout space, increased natural light into classrooms and provided aspect/views from internal-facing rooms. Additional access points have been introduced, all of which are ramped, making this an accessible space for all to enjoy.

Ground Floor Plan: diagram highlighting the extent of SWA’s work at ground floor level at William Ellis School
First Floor Plan: diagram highlighting the extent of SWA’s work at first floor level at William Ellis School
Thermal Comfort & Environmental Design

A 1930’s description of the existing school building when it was completed highlights the school as being innovative and forward thinking in terms of well-being and design, with a focus on light and ventilation. In line with these early ambitions for the school, the focus of this retrofit was natural ventilation, good day lighting, improved thermal comfort/control and increased connection to nature promote healthy indoor conditions for the occupants and provide low maintenance solutions, with a focus on longevity.

Historic photo of original school frontage, including original windows
Photo of the school frontage following the refurbishment works, highlighting the new windows

We worked closely with OR Consulting to gauge the current overheating model in several classrooms and the school hall, ensuring that the window openings were designed specifically for optimum ventilation rates and reduced overheating. Opening windows are now top hung and low level, creating more accessible opening mechanisms for the school users.

The degraded single glazed frames in a timber surround were replaced with a single aluminum unit with a U-Value of just under 1.4 W/m²K, compared to the previous U-Value of around 5 W/m²K, and g-values were carefully considered to avoid overheating. The new ventilated canopy design to an external walkway that runs alongside the hall means that the opening of high-level windows are no longer blocked and are instead enhanced by drawing in cool air from the external walkway and extracting it at high level above the canopy.

Before (left): uPVC conservatory structure to walkway, blocking window openings and causing overheating. After (right): new, external aluminium canopy, designed closely with the existing window geometry as part of natural ventilation strategy

A leaking first floor extension was stripped back to the primary timber structure (which could be saved and retained) and re-constructed with improved thermal performance, including a new continuous, insulated dormer to replace a series of multiple uninsulated dormers which were performing badly.

The windows on the heath-facing, north elevation have been increased in size to allow more natural light into previously very dark classrooms, improve ventilation and provide enhanced views of the Heath beyond. Full height, glazed panels have been positioned opposite the south facing windows next to each internal door, further enhancing natural light in classroom spaces, without causing overheating.

Early conversations and design development with the London Borough of Camden planning department were critical in developing proposals which balanced improved performance with heritage constraints.

For example, to balance the desired thermal improvement of the windows with the important heritage value of the existing, the simplified window design is inspired by the geometry and colours of the original critical and timber frames. The key feature of the historic crittall and timber windows was the use of the two colours, notably a dark green, and this is something that was retained and celebrated within our proposal.

Studies of the window design, developed with LB Camden. Existing (left) to final proposal (right).
Robust and Long-lasting Solutions

Longevity was critical for this project, creating simulating learning environments with health & wellbeing at the heart, whist ensuring specification is robust and long-lasting to reduce cost on client and planet. The specification was developed closely with the school to ensure that an efficient maintenance strategy was in place that could reduce running costs. A balance was struck between choosing longer lasting, natural products and aligning the new proposal with the school’s existing specifications.

Replacing what was previously a combination of timber and steel frame, each aluminium window unit is an integrated system, therefore, the fitting of it is much quicker and more cost effective and there is less room for error. This meant that the installation was more efficient and less disruptive to the school and local area. In addition, the maintenance requirements and associated costs for the aluminium windows and doors are significantly reduced compared to the previous crittall/timber windows. The metal/timber nature of the original windows meant that they could be recycled and the new aluminium windows can also be recycled should the building ever be demolished.

Photographs by Beccy Lane