It was when I began finding empty beer bottles inside half-built cupboards that I first suspected Ziggy’s heart was not in the job. My suspicions were confirmed when I came home another time to find him sitting on an upturned bucket amid the rubble in what has since become the master bedroom, serenading the au pair with my guitar.

Having a live-in Polish builder to renovate my house around us seemed a clever – if unorthodox – solution to a perennial problem. After years of neglect, the large three-storey house we had just bought in south London needed complete renovation, but our experiences of British builders were painful – the local lads meant to start the job demanded £1,000 in cash “to buy materials” and disappeared without trace.

The great Polish influx was just beginning – and Ziggy, a genial chap with a ready smile, was like a breath of fresh air. While British builders would suck their teeth at every setback, his response was always a cheery “no problem”.

And so he worked his way through the house, plastering, repainting, rewiring and plumbing as he went. We paid him much less than a conventional contractor, but he got a place to stay – or rather camped in a room not yet done up, moving on when it was finished.

The results seemed good, even if not as cheap as expected – though still a lot less than a conventional builder – and Ziggy became part of the family.

Before he left, the roof began to leak. “No problem,” said Ziggy, who proceeded to spend what seemed like weeks up there. Maybe his mind was on the au pair – or on his wife back in Poland. Or just on the beer.

Then gradually we began to understand the full horrors of what he had done. His response to the damp creeping up the walls was to cover it with plasterboard; cracks appeared in the walls where he had opened up the attic to create a loft-like space. A structural engineer who visited found he had removed so many ties the roof was in danger of pushing out the walls.

Our electrics are also alarmingly idiosyncratic. Flip the fuse marked “dishwasher” and the light in the top bedroom goes off; touch the metal light-switch covers and you feel a slight tingling. It could have been worse: a friend of mine for whom he did some work found a bare wire under a rug.

Several years on, the house is still standing. But bit by bit we have found ourselves redoing most of Ziggy’s work. Next up is a shower high in the house that has begun leaking so badly anyone standing on the landing below can wash at the same time.

Next time I do anything on this scale, I will put the job out to tender in the usual way. With building, as with so much else in life, you get what you pay for.

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