THERE is nothing surprising about getting on a bus to go to the theatre, jetpacks still not having become standard utilitarian transport. But with Grid Iron Theatre Company, boarding the coach is often the first step after you've had your ticket checked. The company, which is celebrating its 21st birthday this year, discovered the space that became the Underbelly Fringe venue for an early adventure and has since made theatrical experiences in a Norwegian fjord, a cancer hospital in Jordan, the city morgue in Cork, Debenhams on Princes Street, air-side at Edinburgh Airport, the climbing arena at Ratho, and in many children's swing parks. Until a week tomorrow they are installed in Shed 36 at the Port of Dundee, a vast hangar on the way to Broughty Ferry overlooked by oil rigs berthed for maintenance on the Tay. Becky Minto's industrial set echoes those structures for writer and director Ben Harrison's history of the human race's relationship with the black stuff, and how it continues to shape relationships in Scotland as the North Sea boom slows to a trickle. By odd coincidence, Crude, a show long in gestation, at come to production at the same time as a new play, Oil, has debuted at the Almeida in London – written by Ella Hickson and directed by Carrie Cracknell, both of whom have worked in Scotland, and starring Scots Anne-Marie Duff and Brian Ferguson. The unique selling point of the Grid Iron show is that it is not in a theatre and seeing it involves becoming part of a community of strangers visiting an unfamiliar and apposite location.

There is no denying the power of that simple strategy, although the production difficulties introduced are immense. Grid Iron's collaboration with the National Theatre of Scotland on Roam at Edinburgh Airport (bus from the Traverse) remains one of the classiest examples of such work I've seen, while Cora Bissett's multi-award-winning Roadkill, about sex trafficking derived a deal of its power from taking the audience (by bus from the Traverse) to a cramped seedy city flat. It could hardly be further from the aesthetic of Scottish Opera's revival of The Marriage of Figaro, which also opened this week, and yet that company's music director Stuart Stratford has regularly expressed a wish to take opera out of the usual venues, and not just on the model of the current small scale touring version of Donizetti's The Elixir of Love. He has in mind the vast community-cast productions Graham Vick has created with the Birmingham Opera Company in post-industrial spaces. That company's website says: "We don't have an opera house and we don't work in conventional theatres. We conjure our theatres out of spaces used for other purposes or maybe just abandoned. A brief period of illumination and then we move on - not tied to bricks and mortar…" Remind you of anyone closer at hand?

Scotland's "theatre without walls", the National Theatre of Scotland will of course move soon into its new home in Glasgow, as Phil Miller wrote in this section last Saturday. Since then, the NTS has been remembering its first production, Home, which was ten site-specific shows staged all over Scotland. But a decade on, the anniversary event Home Away, although involving international input, has been confined to Glasgow's Tramway. For all the riches of the programme, that seems a little disappointing. It might be pricey and difficult, but taking the show out of theatres is well worth the investment.