St James's Hospital has a remarkable new mortuary building that brilliantly juggles the practical and the spiritual. Emma Cullinan reports.

While clients may chose their architects carefully they can't always be absolutely sure of the type of design they will get (and some probably don't really care).

St James's Hospital has a remarkable new mortuary building as the result of appointing an architect who really cared about the project.

The architectural firm of Henry J Lyons and Partners was commissioned to replace all of the St James's buildings that had to be demolished to make way for a Luas line through the hospital grounds. The new tram just adds to the feeling of chaos on this extensive, low-rise, city site, which rush-hour traffic uses as a rat run. Yet at the entrance is the serene, dignified new postmortem suite and mortuary chapels.

In commissioning Henry J Lyons, the clients acquired a team, headed by director Derek Byrne, who has always wanted to design a chapel and took a great interest in balancing the functional medical needs with the spiritual aspect that this building entailed.

He cites Erik Gunnar Asplund's Woodland Crematorium in Sweden as an inspiration, but there are shades of Carlo Scarpa's Brion Cemetery in Treviso, Italy, here and the natural light streaming down through a slit on the chapel is reminiscent of Le Corbusier's Notre-Dame Chapel in Ronchamp, France, with which it also shares stuccoed walls.

Many architects have since used bands of natural light successfully in chapels, such as Jorn Utzon's Lutheran church near Copenhagen, and in Scarpa's cemetery "the slots of sky glimpsed through fractured openings hinted at infinity", according to William Curtis in his book Modern Architecture Since 1900 (Phaidon).

While the quality of design may not be a major conscious concern to the bereaved, if such buildings are impersonal and don't function well they can add to stress. Ironically, the architect Asplund was one of the first to be cremated in his Woodland Crematorium. The scheme marked the beginning and end of his career - he won the cemetery project in a competition in 1915 and he then added the chapel in 1940 near the end of his life.

The St James's building is not only a postmortem suite but also functions, in a great many cases, as a funeral home as well, where families and friends come to view the bodies of their loved ones. The fact that such a building houses the dead and bereaved, plus staff, requires a juggling act between the practical and spiritual. In this building great care has gone into accommodating various needs, through both circulation routes and choice of materials.

The pre-cast concrete building is enclosed by a white polished concrete wall which surrounds the car-park and terrace to the northside and becomes part of the building itself to the south.

This allows for a sense of privacy and enables the building, which sits right at the hospital entrance, to step back from view slightly. This discretion is enhanced by the fact that the building is accessed through a landscaped area (not yet complete), and sits, on the southside, on short columns as if it's floating away from its hectic surroundings (a feeling that is enhanced by strip lighting that runs at the base of the exterior wall).

A lot of thought has gone into just how the living and the dead are accommodated and where they come together. Hearses and ambulances drive in through a quiet street to the north of the building, rather than down the main street in full view.

The deceased are taken into an area beneath the building from where they are taken up a lift and through special corridors into the chapels or postmortem suites. The public come in through separate entrances: students have access to a viewing corridor above the postmortem rooms and the bereaved enter a waiting area beside three small viewing rooms, or chapels, and one larger one. The building and interior rooms are small but this does give the place a human scale.

Medical facilities tend to be plant heavy, in this case there are services beneath the ground (which had to be cleared from beneath the Luas tracks) and in the top part of the building to the east. This gobbled up chunks of the limited budget.

Aesthetically, it's easy to see where the rest of the money's been spent. The staff quarters are plain and functional and could be in any hospital building anywhere, but the public parts are beautiful: serene and pleasing without being gloomy.

The chapel area is entered through a huge glass door into a seating space that carries the concrete through from the exterior: on the walls and floors that are interspersed with funereal black granite. The doors into the large and small chapels are made from walnut with surface-fixed electronic signs. These give the name of the person within and are more dignified than the standard pieces of paper that used to be tacked onto the doors, says the architect. A large walnut bench, upholstered in leather, lines the north wall which is punctuated by a huge glass window.

Such natural light was a consideration in all of the chapels which run down the centre of the building. The chapels are often used in the afternoons, something the architects took into account in the installation of high windows to the south, which sit beneath the overhanging upper part of the building. Like the short columns beneath the south wall, this also gives the building an ethereal quality.

In a western corner of the main chapel is a large floor-level window looking out onto a gravelled courtyard landscaped by Desmond FitzGerald: a quiet, bright contemplation space. Concealed lighting behind panels and beneath benches adds to the sense of serenity: when people gather at times like these there can be so much emotion but a lot is unexpressed, and similarly in the building, all of the services are present but the design has kept them subdued and hidden.

The exterior actually expresses what happens within the building. The top floor, clad in copper-green aluminium, houses the postmortem rooms; the polished concrete layer below encloses the waiting area and chapels, and the level below ground is for cars and storage.

Derek Byrne was keen to have a flush facade to achieve a dignified simplicity. It takes bravery to avoid overhangs or sloping roofs in our rain-swept land but he feels happy that the aluminium will fight off some of the weather and hopes that maintenance will keep the facade clean. Flush facades risk being boring but this one has clever punctuation in the form of a gap between the green aluminium and polished concrete below, akin to the notches in Frank Lloyd Wright's Guggenheim Museum.

Slits in the green wall are both functional (louvred to protect from southern sun and to let staff see out without the public seeing in) and beautiful. This balancing act has been carried through to the composition: the green metal, and white and grey concrete work well together; the columns that separate the two parts of the elevation have a slenderness and rhythm; and the various external elements join successfully, sometimes crossing over, or seeming to plunge into each other.

"I really wanted to get the chapel and the public area right and give it dignity," says Derek Byrne.

"These buildings are often designed to technical medical requirements but here I wanted to address the building holistically to take account of spirituality and the mind, which often get ignored."

The architects have created a building that exudes calm in a sea of activity. The clients found someone who cared and credit should go to them for enabling this building to happen. But such gems shouldn't appear by chance - all of our hospital buildings should be as good as this.