The original one-off home remains one of architecture’s most potent calling cards - without Frank Gehry’s creatively ramshackle home in Los Angeles in the 1970s, for instance, there could have been no Bilbao Guggenheim in the 1990s. Come to that, without Frank Lloyd Wright’s amazing run of pioneering “prairie houses” in the American Midwest in the early 20th century, there could have been no original New York Guggenheim in 1959. Richard Rogers designed an early house for his mum. That’s not to say that these two are a Gehry or a Wright or a Rogers, but you can say with fair confidence that an architect who designs a good house, can design a good anything. The house is architecture’s base camp. A house is also a miniature city. This is why it is the most restlessly reinvented building type of them all.

This one lurks down at the end of a tatty cul-de sac beside the broad metal skein of railway tracks leading to King’s Cross, a mile or so away. The site used to house a forge that repaired suspension springs for taxis. Which was curiously appropriate, as it turned out, since the house now built there sits on springs to iron out the vibrations from the rumbling trains.

It’s a big patch of land, for London, and was relatively cheap when they bought it, still operating as a forge, back in 1994. Now, the architect couple joke that what they should have done was get all entrepreneurial, design a cute little cluster of homes called something like Old Forge Mews, and made a commercial killing. Oddly, this never previously occurred to them. “Instead, we built a folly,” says Wigglesworth cheerfully. A £500,000 folly - though the office part, with a floor rented out, is a paying commercial proposition. They designed a house based on the principles of their overcluttered, messy, kitchen table. It is an expression of fruitful domestic chaos. Minimalism? No thanks.

The house is effectively three linked buildings. Standing right on the edge of the railway tracks is the two-storey office wing, perched up on spring-loaded concrete stilts buried in gabions - the rubble-filled mesh cages you more usually find holding up motorway embankments or sea defences. The wall on the railway side is clad in stacked sandbags - “Just like the Cabinet War Rooms in Whitehall,” Till observes. Only here the sandbags are to absorb noise, not blast. The rest of this wing, oddly but logically, is wrapped in a quilted grey overcoat - visible waterproof insulation, doing just what a coat should do.