Why theatre is at home with the domestic

Artists' Open Houses has done it for the visual arts. Amateur pop-up restaurants have done it for fine dining. And bands such as the Libertines and schemes such as Unlit have done it for live music. Now theatre, too, is moving into ordinary people's homes, making a literal reality of kitchen-sink and drawing-room drama. In fact I've spent so much of this year's Brighton fringe being marched round residential backstreets to watch pieces staged in people's sitting rooms, kitchens, bathrooms and backyards that I'm beginning to feel like I'm flat-hunting.

The leader of the pack is Wonderbar Productions, whose Small Space is a play about domestic intimacy designed to be staged in people's kitchens. Written and devised by real husband and wife Jane Nash and Dan Milne, and featuring a married couple also called Jane and Dan, it turns the host's home into a living set. Ceiling fixtures and lamps stand in for a lighting rig. Plates and mugs, hob and toaster are used as we watch Jane and Dan make late-night snacks and morning tea. The manner of staging fits beautifully with the script, which explores the way we collaborate and contradict each other when constructing relationship narratives.

Small Space panders to the nosy parker in us all, while bringing what happens in the play closer to our own lives. It combines the cosy intimacy of a real home with the common dinner-party unease of being in a couple's house while they're having an argument. And it reminds us that – at dusk and with the curtains still to be drawn – every home presents the passerby with a possible stage set.

For the theatergoer, drama in domestic space is a different experience again when the venue is the performer's own home. Billy Budd, which I've discussed elsewhere on this blog in relation to nudity in theatre, is currently being staged in the actor's Brighton house – his bath, to be precise. You sit next to a shower cubicle full of his family's toiletries, or perhaps on his toilet. The frisson of voyeurism is heightened, as theatre goes where webcams dare to tread.

The use of real homes presents the sound designer with a whole new palette, too. I loved hearing the bath running down the hallway before Billy Budd, and Dan's voice calling from upstairs in Small Space. In another Brighton fringe event, A Live Trail, I sat blindfolded in a sitting room for a wordless vocal piece by Brighton's Grrr, their growls and grunts echoing down the narrow hallway before creeping across the carpeted room. As the familiar household acoustics augmented the outlandishness of the noises, I thought of Steven Moffat's recent observation that Doctor Who is scary because it is rooted in the domestic – the monsters under our beds.

The theatre behind A Live Trail, the Nightingale, has just renamed all its spaces to reflect the building's former function as a hotel. Until 29 May, Entre Les Mots will be baking for and performing Picture a Spoonful of Silence in what was once the dressing room and has now reverted to "the kitchen". Meanwhile, original domestic fittings are furnishing a rich artists-in-residence scheme: performance artist Wendy Houston moved into the Nightingale for a month in 2010, filling it with her belongings and putting on informal performances to which the audience was able, like friends on a casual visit, simply to drop in.

Where so much site-specific work tries to sensationalise theatre-going, the primary intention here seems to be to normalise it. But as I ring the latest doorbell and step over yet another threshold, I start to wonder what this is doing for the concept of theatre as shared space, mutually owned by both audiences and cast. One thing is for certain about our homes: they're never neutral ground.