My new writing shed is nearly finished. The door isn’t on yet but it arrived earlier in the week, bringing with it the promise of closing and locking from the inside, of quiet time to write or at least think about writing. It’s a stable door made from oak so I can open the top half and my Girls – Blithe, Blanche and Dolly, the bantams – can do their funny little flappy hop-ups and perch there clucking at me. They love watching me peck away at my keyboard.

The top half of the door has four panes of glass, which means it’s mostly window. I considered another door with a single small pane but it made me think of prison or mental hospital where a key-jangling warder’s face suddenly looms filling the whole frame. Which made me think of the things I might do to end up in such a place.

We recently moved from a small flat with a big garden and a 15ft x 12ft shed at the far end to a terraced house with a cosy garden and a sagging potting shed. There’s plenty of room for me to write in the house – a whole room if I want it. But I can’t. I mean, I can, obviously. But I can’t. Aside from the fact that we’re still stripping the syphilitic woodchip and the floors have yet to be sanded and my books are all in boxes, it’s where I live.

When I was writing Maggie & Me, the memoir published last year, I would stumble down the garden every morning before I was really awake, let my Girls out, then sit down in my shed. There I would write myself back to 1983. I imagined it taking off like Dorothy’s house in the twister and crash-landing in my past, ideally on top of the last man to hit me and get away with it. When I was done for the day, or night, I would leave my shed, leave my past, and walk back up the garden into my present.

That memoir contained things and my shed contained the process of getting them all down. To go there, or anywhere else, again, I need a safe space. I justify the expense by pointing to Roald Dahl, Virginia Woolf and Dylan Thomas.

So, my new shed is being built by a soothing carpenter called Guy who looks lovingly at plywood, seeing only potential. I’ve given him terrifyingly specific instructions: I mustn’t be able to touch the roof from the inside, for example. I am 6ft 3½in – the half is very important.

So Guy got his measuring tape out and I put my hands above my head and did the little jump I do if frustrated or excited. Guy marked an inch above that point. The roof is cedar shingle, which has the added benefit of keeping moths away – I have lots of writing cardigans so this is actually an exciting unforeseen benefit.

I hate noise when I’m trying to work, to the extent that I’ve complained to myself about my own heartbeat. At our old place the neighbours had a trampoline that their children never seemed to grow out of. I considered buying them an X-Box. I got on first-name terms with the noise pollution lady at the council who helped me turn the volume down on a delusionary “singing” teacher and a karaoke-prone pub.

Our new neighbourhood is more peaceful but Guy is leaving no sound to chance. He has sealed every joint with some weird expanding foam. Thick woolly stuff fills the cavities, which will soon be lined with tongue and groove. The desk-height windows are double-glazed. Step in and the air is still, pleasantly dead. Even without a door. Soon it’ll be on and I’ll close it behind me and sit down. And then?