Discover how Karl Harrison transformed a sloping London playground into a multi-use school decking amphitheatre with Millboard and Thermo-pine.
Some playgrounds need more than a lick of paint and a few painted lines. This junior school in London wanted a proper stage for imagination. HMY Architects designed a five-zone decking scheme and asked me to design the structure to Eurocode 5 (EC5) and bring it to life during the short summer break.
The result is a compact outdoor world: an amphitheatre, a performance stage, hiding spaces, quiet corners and viewing platforms. All squeezed into a sloping tarmac playground that previously offered very little more than somewhere to queue.
Five zones, one simple idea: play more
The scheme uses five distinct decking areas that flow into each other.
Children can climb onto the curved stage and run their own X-Factor auditions. They can duck into the enclosed hideaway to whisper secrets or plan the next game of hide and seek. Teachers gain a simple outdoor classroom: the stepped amphitheatre lets a whole class sit, listen and take part in group work.
Another zone creates a higher decked platform that evens out the fall in the playground. It feels like a balcony and works brilliantly for small groups or reading time. Everything links back to the central stage, so supervision stays easy, and sightlines remain clear.
Millboard and Thermo-pine: robust materials for school life
HMY specified two key materials:
- Millboard Enhanced Grain in Limed Oak for the main walking and seating surfaces.
- Thermo-pine from Brooks for the vertical cladding and curved forms.
Millboard works very hard in a school environment. The boards look like timber, yet they resist rot, splintering and most staining. The surface offers excellent slip resistance, even when wet, which matters when children charge out of class in the rain. Because Millboard never needs oiling or staining, caretakers avoid a long list of maintenance jobs.
Thermo-pine brings the warmth of real wood without the instability of standard softwood. The thermal modification changes the cellular structure of the pine, which means less movement, improved durability and fewer visible defects. It also offers a more sustainable alternative to many tropical hardwoods, which fits well with the school’s environmental values.
Structurally sound, but still playful
Under the skin, the project needed to perform like any other engineered structure. I designed the subframe to EC5, taking account of the curved geometry, changes in level and the live loads that a busy playground creates. Every connection, joist and support spreads the load safely into the existing hard surface.
From the children’s point of view, they simply see smooth curves, strong balustrades and clean detailing. From the school’s perspective, they gain a robust structure that stands up to daily use with minimal ongoing cost.
Built in the summer break
The entire project had to fit within the tight window of the summer holidays. We prefabricated as much as possible, then installed quickly once the playground was clear. When pupils returned in September, the new decked world greeted them on day one.
Teachers now use the space for storytelling, group work and outdoor assemblies. At break times, the children turn it into anything they like: a ship, a theatre, a castle or simply a place to sit with friends. The decked surfaces, steps and screens create subtle boundaries without feeling restrictive.
Does your school need a space like this?
If you look out at a tired, sloping playground and see wasted potential, this project shows what is possible. With the right mix of Millboard, Thermo-pine and careful structural design, a dead corner can become a multi-use stage for learning and play.
To explore ideas for your own school decking amphitheatre in London or beyond, get in touch with Decking by Karl. Let’s turn plain tarmac into a safe, low-maintenance space where children can perform, learn and imagine every day.
