Charlotte Mendelson: Inside the novelist's ideal home

Charlotte Mendelson thought that houses in the London enclave where she set her novel were all out of reach. Then she found the perfect doer-upper...

We've just moved to a house that's eight minutes' walk from Hampstead Heath, in Dartmouth Park. We moved from a three-bedroom maisonette opposite it – which was lovely, but it was bulging at the seams.

We'd made offers on various houses in Tufnell Park, which is nearby, but our hearts hadn't really been in them. They were mostly compromises, or they were horribly overdeveloped – lots of downlighters and strategically placed tiny shower-rooms. Meanwhile, our neighbour kept saying, "I don't want you to move", and we'd say: "But we can't afford a house in Dartmouth Park!" Then late one night she knocked on our door and said: "Do you know the people opposite are about to put their house on the market?" We spent most of the night desperately trying to get hold of them – they weren't living there – and then, at last, we succeeded.

When we saw the floor-plans, our hearts sank, because the garden looked tiny. Then we had a look around, and just fell for it. This all happened last summer. We know we bought at the worst time, when the prices were at their highest, but we sold at the best time and got a good price for our flat over the road. I don't think prices are going to plummet here.

The surveyor said the house was 1900 but various people think it's more like 1880s. It feels almost Georgian, because it's flat-fronted and has big, wobbly, rippled panes of glass and very deep skirting boards. I like to think it's really 1700 and nobody noticed it before then. The reasons we love it – wonky stairs, creaky floorboards – are all reasons that anyone sensible would buy somewhere else. But every single person who's been in and looked around has said that the house has a really good feeling, and although I'm not remotely soppy about that sort of thing, I think they're right. It's a familyish, characterful house, and that's exactly what we were hoping for.

Ours is quite a noisy road, but it doesn't bother us; there are lots of intriguing neighbours to speculate about. This part of London is fantastic: lots of interesting people. When I was writing When We Were Bad, my third novel, it was always going to be set around here, because it's so odd and interesting. It reminds me of Oxford, where I grew up, but less exhaustingly brainy – an ideal setting for the story of a perfect family falling apart. And so it reflects my love of the area – lots of scenes on the windy Heath. I think detail like that adds to fiction, because it shows you what the texture of the characters' lives is like.

The move was just as exhausting as any other. It's amazing how many people say, "Oh, didn't they just carry stuff over the road?" But what with the traffic, and all our books, how could we do that?

On the ground floor there is a room at the front that is officially a bedroom, where at the moment I write. Next to that is the kitchen, which has grey and blue units – very Eighties, and all about to fall down, but it faces south-east, so the most enormous quantity of light pours in all the time. There's also a long hall, a tiny loo and a dismal shower room – and, most exciting of all, an under-stairs cupboard; I've always wanted one of those.

We're going to knock through the wall between the kitchen and the bedroom. Some people have enormous kitchen extensions with lots of glass, but we don't want that because we love our garden and I've been bitten by the vegetable-growing bug, so I need the flower beds for kale. It's an old brick courtyard with a fascinating view of neighbouring houses. The other day my daughter said: "I can see a naked man." It's a real Alfred Hitchcock Rear Window house.

There is the most beautiful, elegant, curling banister going upstairs to the first floor, where there's a door to a roof terrace, and a big sitting room with a fireplace. Parliament doors divide the sitting room from a lovely study. One of the reasons we moved was so that Joanna and I could each have a study.

The second floor has three small bedrooms, a bathroom and the best thing in the entire house – a deep, old built-in cupboard covered with hundreds of years of gloss paint, which we are using as a games cupboard. It would be fantastic if we could extend up into the loft, because the bedrooms are tiny, but I don't think we would be allowed because this is a conservation area.

We paid £800,000 and moved in December. The previous owners moved in almost in the year of my birth and then didn't do much to the house, so it needs all sorts sorting out. The bay window at the front is basically falling off, other windows are rotten, and there are lots of different sorts of damp. The idea of having builders in fills me with dread, but I couldn't live in a house that someone else had dolled up. I'd rather we lived through the work, miserable as that will be, but still keep the feeling of the property. What I love about this house is that it's old and creaky and delicious, and the work we do won't make it a glass and steel avant-garde style house; it will just make it sound.

To buy 'When We Were Bad' for £7.99, with free p&p, call Independent Books Direct on 0870 079 8897

Charlotte Mendelson's second novel, Daughters of Jerusalem, won the Somerset Maugham and John Llewellyn Rhys prizes; this week her third, When We Were Bad, was longlisted for the Orange Prize. She has a son, eight, and daughter, five, and lives in north London with the novelist Joanna Briscoe.