A butcher's former cold store in a busy village has been turned into a contemporary office without upsetting the planners or the client. Emma Cullinan reports

"We painted the building black because, as it was north-facing, we wanted to celebrate that fact and embrace the darkness," says Orla O'Callaghan, architect of a small office building at the rear of a butcher's shop in Dalkey, Co Dublin.

Persuading the client took some doing - and pacifying words such as "deep charcoal grey" were used - but, as Orla O'Callaghan says, with a building of this size you can try such things and re-do them if they don't work. Painting the exterior of this office costs €200.

The building is small, it has a sun-lacking aspect and sits in a backland but therein lies the part of its success. Schumacher's oft-quoted comment about the beauty of small things applies here and shows that even a minute construction, costing less than €160,000, might as well be done well.

As the client, Edward Doyle, says: "The architect's attention to detail throughout the construction has given me a building that has far exceeded my original expectations."

The fact that the office was to be built in a backland meant, probably, that the planners weren't as concerned with its appearance as they would have been if it fronted Dalkey's main street. It also meant that the client wasn't as precious about it and so the architects were pretty much left to get on with the job.

The new office, which has taken the place of a former cold store and sits in a courtyard which was previously an abbotoir, was built loosely along modernist lines. As with most architects who care about design, Orla O'Callaghan works out details that don't add to the cost of building but add substantially to the building itself.

When working within a budget (and when don't you?) you need to detail carefully and spend the money on the crucial bits, she says. In this case the big spends went into the steel double-glazed windows and thin, cantilevered concrete stairs.

These were made on-site and look far less clunky than the usual exposed concrete stairs in which the underside runs in a straight, diagonal line with all of the concrete filling in to that line. In this building the underside follows the line of the stairs.

The slender skirting on the walls and stairs is recessed in another example of fine detailing that doesn't add to the cost of building.

To add to the lightness of touch, there are no uprights supporting the stairs or, indeed the first floor. The ground floor is free-flowing and the stairs are suspended in space.

This is achieved by having the first floor held up by the roof, in a steel-frame construction. This maximises the use of the small ground floor plate.

What does sit in the ground floor is a bathroom clad in tongue-and-groove ash.

The idea of the building is a box within a box and creative detailing has left a line around the top and edge of the bathroom, lifting it from the wall and ceiling so that when the light is on inside it, the inner box is visually separated from the outer one.

Slithers of light are used upstairs too where, apart from the huge windows to the north and east, there are slits cut in the steel roof, above the stairs, to haul more natural light into this shadowy site.

"The slender openings light the stairs and wash the white wall for a greater sense of space and stops that corner of the room dying on you," says Orla O'Callaghan, who graduated from DIT in the 1980s and spent a year working in Amsterdam before returning to Ireland.

A tall, thin opening above the front door allows visitors to see right up through the building and, says the current tenant, this lets in streams of sunlight to the top floor during the afternoon.

This isn't ground-breaking architecture, in terms of form, but perhaps that's not what's required in the Dalkey backlands. This is a simple box and can seem austere in places: the concrete ground floor may be covered in rugs by more conventional tenants, but its industrialness and elemental honesty does have appeal.

The architect kept the pallette of materials simple: using steel, concrete, glass and timber.

"Just because you can use a lot of materials, you shouldn't, especially in a small building. It's so tempting to overuse materials but you need restraint," says Orla O'Callaghan, who now teaches at her alma mater and runs her own practice.

The building could have been slightly larger but car-parking spaces to one side were catered for.

In large cities, such as London, there is change afoot. It used to be the case that planning permission would be difficult to get if you didn't have car-parking spaces, yet now there are cases of planners objecting to buildings on the grounds of too much car-parking provision.

In the US there are stories of car-parks being positioned away from buildings to encourage people to at least have some sort of a walk to work, in the fight against growing obesity.

In Dalkey, car-parking requires a sixth sense, as there are lots of places where you can pay and park, but no indication of where to hand over the money. So, for the time being, tenants of this office building get to park outside.

The careful detailing and thought that has gone into this office shows how such consideration throughout a building pulls all of the constituent parts into a pleasing whole. Even the daring black exterior (like the render used to gloomy effect by Daniel Libeskind on his Manchester war museum) works, framing the elements within.

Such celebration of shadows even convinced the client, who has now commissioned more work from the architect on an adjoining site.

"I think the way the architects cut the roof to allow the sunlight into the back of the building is tremendously powerful, as is the external black colour which I am now delighted to have been persuaded to use," says Edward Doyle.