The architect said assembling the furniture requires no instruction other than "two minutes of common sense".
Each piece is constructed from five components, all of which can be cut from a single sheet of birch plywood. According to Stummel, this was the minimum number of pieces that the architect needed to get complete stability for the frame.
"It takes so long to have anything made in England. These 2D cutouts were an epiphany: you can send off a design and get it back the next day," he said.
With just one piece of plywood per item and the upholstery for each set of cushions created from just one leather hide, each piece can be created with almost no waste.
This aligns with Stummel's architectural approach, which favours things that last a long time and reflect how they are made.
The architect came up with the idea for the sofa while he and his wife were looking for furniture for their Shepherd's Bush home, Tin House. The property, which was shortlisted for the RIBA's House of the Year award in 2016, comprises a cluster of red metal-clad pyramid-shaped rooms arranged around a courtyard.
"In part it was that my wife wanted a sofa. But in part it was also that the first Brexit fear was going through the market and there wasn't really much to do," Stummel told Dezeen.
The sofa frame is designed to be resilient and have exactly the right angles for comfort. The cleverness of the simple frame is then paired with leather cushions to offer a more luxurious experience.
"The frame is just a useful vehicle. The surface is what makes the experience of the sofa; the leather transcends time. That's where the focus is, where you sit, watch TV and fall asleep," said Stummel.
The leather cushions were crafted by father-and-son design team Phil and Sam Timings from Uptec, a furnishing company based in the Cotswolds. The designers use high-quality aniline cow hide for the collection, treated with a blend of oil and wax.
The result is a natural-looking wash with a distressed finish that celebrates the imperfections in the leather instead of masking them.
Stummel thinks the furniture will appeal to young people in London who can't afford to buy property, meaning they might move many times before settling into a more permanent home. He suggests they will want to buy furniture that can move with them.
"That's why flat-pack is so great. Ikea flat-pack has all these funny little pieces that you need to build it, so you construct it and never take it down," he explained. "With Nomad you don't even need a tool. No glue, no nails; you just slot the pieces together. It's so easy."
Nomad will be on show throughout London Design Festival at Tin House, 2 Smugglers Yard, Devonport Road, W12 8HU.