Representative of the changes currently taking place on the Sandyford Industrial Estate is a planning application for the redevelopment of a site now occupied by Carrolls. The building there at present is very typical of the older offices constructed in the area, a modest and decidedly uninspired two storey redbrick block.

Should permission be granted, this will be replaced by two structures, one rising to four storeys with a penthouse on top, the other to six storeys with an eight-storey tower and underground car-parking.

Given that so many other old buildings on the industrial estate have been, or are in the process of being replaced by larger and taller office developments, it seems highly likely that this site's character will change as outlined in the planning application.

But the fate of the Carrolls block demonstrates the primary drawback to what is taking place in Sandyford: the entirely ad hoc nature of the estate's redevelopment and the apparent lack of any overall plan.

Obviously, since the original buildings were of little or no aesthetic value, their demolition was never going to be mourned.

However, the clearance of sites offered an opportunity for the entire area to be given a consistent - and better - character. Here was a chance for the entire Sandyford area to benefit from a coherent strategy, as is expected to be the norm elsewhere. The outcome would have been a showcase industrial estate.

In Sandyford, for example, despite the growing number of people who work in the area, there are almost no public facilities such as restaurants or newsagents. Every unit is self-contained and the broad roads between them are almost devoid of pedestrians; despite its manageable size, this is an environment in which cars predominate.

Unfortunately, the opportunity for a fundamental re-evaluation of Sandyford's character and appearance has not been taken. As a result, the faults inherent in its original design remain. Some of the newer developments might be highly regarded in any setting; others should never have been permitted.

The architectural practice which has made the greatest impact in Sandyford is Horan Keogan Ryan, responsible for a large body of work there over the past decade. The earliest example of HKR's design is the Sandyford Business Centre off Burton Hall Road, built at the start of the 1990s - and very similar to developments of that time in England.

The redbrick units are two-storey with pedimented fronts, their uniformity relieved by differently-coloured aluminium-frame windows. While no doubt once considered smart, the cosy attempt to create a village atmosphere in the business centre now looks terribly dated and the entire complex seems out of place in an increasingly high-rise environment.

HKR was also responsible for the AIB Financing & Leasing premises nearby on Blackthorn Road. Its design is very similar to that of the business centre, but with the scale greatly enlarged. Similar work by the practice can be found on Arena Road, where an attempt has been made to disguise the solid and none-too-inspiring mass of a redbrick block with corrugated metal roof - currently occupied by Canon - through the addition of a forest-green aluminium-frame canopy and a central clock tower.

At the end of this road, HKR produced a pair of four-storey office buildings sharing the same basic design - yellow brick, aqua blue aluminium-framed windows, recessed top floor - with certain details differentiating one from the other; a third instance of the same work can be found on the junction of Blackthorn and Bracken Road, a property now occupied by Eircell.

HKR's latest Sandyford work is a remarkably sophisticated advance on its earlier blocks in the same area. Now nearing completion is a pair of very substantial buildings for Green Property called the Atrium Office Development on the junction of Blackthorn and Carmanhall Roads.

While in keeping with current trends, the scale of these blocks is much bigger than many of their predecessors designed by the same practice - rising to six storeys and with each site accommodating 177,000 sq ft. Instead of the customary corrugated metal and brick, the offices are fronted in plate glass and off-white concrete panels and, as their name implies, the main feature of both is a central atrium with glazed roof.

The Atrium Office Development certainly suggests a new consciousness of the possibilities of raising design standards for the work environment, and another couple of HKR buildings underway at the moment on Corrig Road look set to continue this momentum. Another recent redevelopment, Ballymoss House on Carmanhall Road, designed by Duffy Mitchell Architects, also deserves notice, although the handsome exterior looks gloomy due to the grey shades in which it has been rendered.

AT the moment it is still too early to tell what will be the finished character of Beacon Court, a particularly substantial redevelopment taking place between Blackthorn Drive and Bracken Road, with frontage also on Blackthorn Road. However, the omens are certainly optimistic for this campus-style series of five blocks built around a central pavilion.

Beacon Court has been designed by Traynor O'Toole Partnership with John Rocha as design consultant. The promise is that all the blocks, varying in height between four and six storeys, will incorporate glass-roofed atriums, make generous use of natural materials such as stone and timber, and include landscaping.

Unlike other office developments in the Sandyford Industrial Estate, Beacon Court is expected to include a number of amenities such as a restaurant, florist, newsagent and banking facilities. Even in its present incomplete state, Beacon Court offers other developments in the area a template for the future.