For my sections I chose to section across an undulating path on a roof garden. this stepped down across a balustrade to a terrace below. It was a visually rich area, with lots going on: changes in elevation, two types of paving surfaces, and a proposed AGB blue-green roof system. I wanted to demonstrate the intricacies I had put into my design.

One of the key requirements in the brief was buildability, so I didn’t want to make assumptions. I actually rang up the AGB roof system supplier and Addagrip to double-check how things would be done on-site. Talking to someone on the technical side helped a lot and gave me more confidence that what I was drawing wasn’t just theoretical.

Then came the levels.

I started by referencing the existing roof slab, but when I factored in the additional 250mm for the minimum AGB build-up, things got confusing fast. The path had different gradients, and I had to interpolate proposed levels between spot heights that were in metres, while I prefer to work in millimetres.

This mix of units tripped me up more than once, on a few occasions I accidentally used 25mm instead of 250mm, or even 250 instead of 25m (thankfully, those errors were caught!). It wasn’t until I had the whole section laid out that I could properly see what was going on and begin adjusting levels logically.

Another surprise came when I tweaked some of the hatches after setting the levels, a lineweight setting must have changed without me noticing. It came through far heavier than intended in the final output.

Despite the setbacks, and the fact that it took me twice as long as I planned, I’m actually really pleased with the result. The detail feels realistic, and I learned a huge amount about how systems come together across a multi-level roofscape.