IT was a dreich day to visit a derelict warehouse on the banks of a canal on the north side of Glasgow city centre, but there was no doubting the excitement in the air.

The artistic director of the National Theatre of Scotland, Laurie Sansom, had unveiled plans for the conversion of the damp, guano-decorated, asbestos-contaminated building, somewhat larger than a football pitch in footprint (as estimated by a posse of ill-equipped arts-hacks), into a new "Centre for creativity, production and talent development" for the NTS in the Spiers Wharf regeneration area at a cost of just less than £6m.

That seems quite inexpensive when you learn that only the bare bones of what is currently referred to as The Blue Shed are being retained by Gareth Hoskins Architects. The Glasgow and Berlin-based practice, which has long experience of cultural facility design and build, is taking away everything that makes the structure blue and sheddy. The walls, and the roof, are going so that an environmentally-friendly complex of rehearsal rooms, technical and wardrobe facilities and administrative offices can be created on the skeleton of the building.

The proposal will result in "a cost-effective, efficient and sustainable operational hub, from which to build the Company's artistic ambitions, productivity and reach, whilst ultimately remaining true to the National Theatre of Scotland's vision as a 'theatre without walls'," as the company's statement put it.

What we must never say is that the NTS is looking to raise £2.5m towards creating "a home". It might seem to some a little like the old medieval theological argument about angels dancing on the head of a pin, but there is a principle at stake here about which the company is understandably very sensitive. The "unique model" of Scotland's national theatre company is that it makes work in theatres - and other "found" spaces - across Scotland as well as, increasingly, overseas. It does not have a monolithic South Bank multiplex to call its own and expressly does not desire one. It was an important statement of intent that the NTS would not suck resources from other theatres in Scotland, but rather help sustain them (although it is also very sensitive about seeming to be another source of funding.) When it came into being nearly a decade ago, the first NTS "show" was ten simultaneous production staged across the country, all entitled "Home" but each a very different interpretation of that theme by teams of artists under different directors.

The difficulty is that no matter how careful the company is in referring to its "creativity factory", the enthusiasm for not having to lease rehearsal facilities wherever they can be found, and being able to see a day beyond makeshift office and workshop space bubbles over into expressing the same justifications that might be applied for a national company having its own building. With walls.

Reasons like it being a nice place to visit. Scottish Canals is very keen on emphasising the tourism potential of this "cultural quarter", and it is easy to see that the new facility will have a winning position on the North Bank of the canal. Reasons like non-professionals who are involved in the company's extensive outreach and education programme finding it exciting to be making work alongside star names.

So the NTS does need to be careful how it regards its Spiers Wharf base. If I am still in this chair when it is complete, I will be unsurprised to be asked to attend some sort of performance there, even if that is currently something that will definitely never happen.