A glass and aluminium extension in Dublin provides a dazzling contrast to the comfy house that it's attached to, writes Emma Cullinan.

THIS extension is on the rear of a classic Edwardian house with its pretty façade that represents the peaceful, idyllic pre-first World War mood. There's the stained glass window over the door and the sloping tiled roof at first floor level; part of the Edwardian penchant for adorning facades with added flourishes.

There are tinges of the Arts and Craft movement here, espoused by William Morris and his ilk, as well as the English country style of Edwin Lutyens, that were all popular when this house was built.

After the war Modernism and the International style took hold and the adornments to houses that grew from the Victorian era onwards were swiped, leaving the essential form of a house, often in white, whose internal spaces flowed in open plans, without the restrictions of blockwork walls as the main supports.

This house, near the centre of Dublin, offers a glimpse of both worlds. You enter in the Edwardian era and emerge into a rear extension that speaks of Modernism. The experience is of moving from a cosy nest-like space to a brilliantly bright room. Humans thrive on a choice of both.

The link between the two is handled well with a few timber steps descending from the old, wooden floored hallway, landing onto the white limestone terrazzo floor that is a main material in the extension.

You are given a foretaste of what's to come without stepping immediately into the dazzling white space, sparkling with nuggets of shiny limestone, which covers the floor, the kitchen kickplate, worktop and back splash and which extends along the wall beyond the kitchen and into the garden. Here the wall becomes a screen that provides a link between the interior and exterior and offers privacy from the house next door. Seclusion from neighbouring windows is also provided by sandblasted glass on the side of the extension.

The hall leading from the old part of the house into the new is lined with flush white cupboards taking the eye along an interrupted line into the extension.

Amanda Bone, of Bone O'Donnell Architects, is keen on flush detailing: for example, the new extension steps down internally, demarcating different areas (from kitchen and dining, to living space). This enables the extension to remain flush with the sloping garden. The kitchen cupboards have been set into a thick wall above the worktop, providing another uninterrupted line.

Having left UCD in 1996 and working in New York and Paris for a couple of years, Bone then worked with Esmonde O'Briain when he set up in practice after leaving DTA (Derek Tynan Architects). After five years Amanda established her own practise and now runs it with O'Briain's sister in law.

It seems brave to set up in practice relatively early while many architects hang on, working in larger companies wondering when the right time will come to go it alone.

The problem can be taking the leap from running large jobs in big firms to going back to small extensions.

But domestic projects are what Amanda is happy with - and she took the initial plunge with two such jobs. Now she is in a position to choose clients and limits herself to three or four jobs a year.

She admits to ascending a steep learning curve when setting up alone and was told it would take five years to feel established: which turned out to be accurate. She now makes sure that she has a couple of projects at design stage and a couple on site at the same time to keep finances and creative juices flowing.

The clients for this extension had seen Bone O'Donnell's previous work in a magazine so both parties knew what to expect. Although the initial brief was to design a kitchen in the existing return, the project expanded.

While many period homes are perfectly lovely places in which to live, the domestic staff often got a raw deal in the poky rooms at the back of houses, and it was these grim spaces which Amanda has dramatically reconfigured. Part of the existing return was kept but the maid's room on the first floor was restructered in order to create a double-height light well in the extension.

The new extension protrudes by one metre from the side of the existing return and a thin glass wall has been put into the projection so that those in the kitchen can look back into the new playroom in the rear of the Edwardian part of the house.

The area to the side of the garden now has three doors opening onto it, instead of the previous one, and dining tables and chairs often spill out into this former dead space.

The garden, which used to be difficult to access, has become so much a part of the new living area that the two are colluding to provide a Mediterranean existence in deepest Dublin. Amanda always insists on designing gardens as well, so that they work with the new parts of the house. Here she simplified the garden which now has a lawn and gravel path plus a white wall at its rear (hiding a shed) to 'book end' the whole composition. The owners have taken this palette and created a border filled with leggy rosemary, punctuated with olive trees and grape vines.

While Bone O'Donnell has a pared style each job is designed to suit the client and the environment. Often the clean backdrop is given a colourful expressive element: in a previous project in Monkstown they designed a house with sloped copper roofs and in this house the drama comes from the aluminium curtain walling in red oxide.

The colour adds delight as well as an industrial flavour due to its regular outing as a coating for brawny girders. In this extension the uprights are more slender with the two supporting steel columns in the living area maintaining a slender profile. The red was chosen to complement the redbrick at the front of the house but as well as linking it to the past in this way it also gives it its own identity.

The fact that not everyone could live in such a streamlined space is reinforced by this house's neighbours. Since this extension was built a Victorian-style timber conservatory has been attached to the house next door and on the other side an addition is being built from copious quantities of blockwork.

The beauty of the Bone O'Donnell extension is that it is attached to a cosier property to retreat into but the main feeling, when walking from the dark into the light, is one of immense calm.