Sketch of Calton Square proposals

Calton Square

Proposals are being put forward by Ardstone Capital to refurbish and upgrade the current Calton Square office building, located at the top of Leith Walk.

Fronting onto Leith Street, Greenside Row (the pedestrian street along the Omni frontage) and Greenside Place, the intent is to create a best-in-class office building. Comparable to the best in Europe, with the lowest possible carbon footprint, this upgraded building will bring significant benefits to the immediate locality. Whilst not formally classed as a major development, and therefore not requiring statutory consultation prior to the submission of a planning application, we consider that proper engagement with the public and other key groups is important especially given the building’s prominent location in the city centre.


The current occupier of Calton Square is moving out in April 2025, and the building, which dates from the 1990s, needs updating and no longer meets prime occupier standards and requirements. To refurbish the building will require significant remodelling and intervention. However, as much of the structure will be retained as possible, including the frame, with materials re-used where able. Sustainability and net zero objectives are a key consideration for the building owner, delivering first class energy and environmental performance standards.


If you want to make comments on the proposals you may do so using the feedback form below, by email to or by post to Orbit Communications, 42 Charlotte Square, Edinburgh EH2 4HQ. Please note that comments submitted at this stage are not representations to City of Edinburgh Council. There will be an opportunity to make representations to the Council if a planning application is made. For further information, please contact 0131 202 3259.

Please note that the deadline date for comments is Friday 1st March.


Why change what’s there?

The current office building is now more than 20 years old. It was a good design that reflected modern occupiers requirements in the late 1990s and early 2000s. Much has changed since then and the building is showing signs of its age and it would not meet modern occupier requirements or current building standards. The reception lobby is very small with changes in levels up and down that restrict access for all users.
It no longer meets best in class standards and there is an opportunity to extensively refurbish and upgrade when the current occupier vacates the building next year.

Are you proposing to demolish the existing building?

No. The proposal is to refurbish and upgrade it completely. This will involve carefully stripping the building back to its frame, setting aside stonework and re using it wherever possible in the new building.

Will there still be green roof terraces?

The new design will incorporate more green roof spaces and terraces. This will improve environmental performance, drainage and rainwater collection; in addition to providing more effective points of access to the roof whilst also enhancing views from Calton Hill.

Will the building get bigger?

Yes, slightly, but not significantly. By better utilising the site in plan form, providing better configuration of the floor plates and adding areas at some of the upper terraces it will be possible to create more office floor space. The most significant increase in gross floor space will be the creation of an enclosed atrium in the existing courtyard. The building will be no higher than the existing tallest part of the building (in fact the highest part will sit marginally lower) and will not impact on the city skyline or protected city views due to upper areas being stepped back.

How much parking will be provided?

The existing 30 spaces will reduce to 8 and will include EV charging and accessible parking. Cycle parking will also be significantly enhanced and provided to Council standards including cargo bike stands and the addition of shower and changing facilities.

What is the environmental impact of the proposal?

As part of the design process our aim is to minimise energy demand and improve environmental performance by incorporating into the design better operational environmental performance. The new building will be all -electric.

Currently the glass to solid ratio is around 30%/70%. We propose that this is reversed to more like 60% stone to 40% glazing.

We are actively promoting occupant wellness by providing different amenities and a high quality environment with improved cycle storage and end of journey facilities to encourage active commuting.

We will also reduce embodied carbon by utilising the existing building frame and specifying carefully selected, low carbon materials inside and out.

The new facade will reduce operational energy use through a ‘fabric first’ approach to optimise passive design measures such as air tightness, sunlight for heat, orientation, glazing position and specification, cross-ventilation and passive cooling.

Do we need more office space in the city centre?

This will be possibly the best office building in Edinburgh – which will attract top occupiers. There is demand for top quality super-prime office space that is not provided elsewhere in the city centre at present and there is limited new stock coming to market over the next few years.

In addition, the stock of secondary space and Grade A offices in sub-prime locations have started to be converted to other uses which has also diminished supply.

Edinburgh needs to maintain ‘best in class’ product in core accessible locations – we believe this location is ‘super prime’.

Why can’t other uses be included such as housing?

The building cannot be readily adapted to residential use. Also, it would be prohibitively expensive and would mean that any housing product would be at a very high cost. There is demand for employment / office use in the city centre with the location extremely accessible by foot, rail, tram and bus and the mix of surrounding uses is complementary. It also provides a good balance with other core office locations at Haymarket and is entirely appropriate for a key city centre site.

How long will the construction last?

Probably around 24 months from start to finish including fit out. This will be very carefully co-ordinated as a city centre site and would include a full Construction Management Plan in the usual manner. Construction, subject to planning etc, could start in the second half of 2025.

Where can the building be seen from?

Largely from local streets around the site – for example the views from Princes Street down Leith Street and up and across from Picardy Place are both very important. There are fewer, glimpsed, views from elsewhere or the building appears a small object in a much wider cityscape or panorama, for example from the Castle Ramparts.

Another key elevated viewpoint is from Calton Hill. There will be a myriad of different individual viewpoints from there but the overall massing and height will not break the backcloth of the St James Quarter or obscure any views to it or the city skyline/roofscape.

The important viewpoints are assessed in detail by a Townscape Impact Assessment and Heritage Assessment as part of the design process.

Will there be another consultation event?

We do not plan to have another public event because the proposal is not classed as a ’major’ application and does not involve complete demolition and redevelopment or any change of use. In fact there is no statutory obligation to have any sort of public consultation event in this instance but we believe it is the right thing to do given the prominence of the site and the interest it might generate so we have also engaged with a number of local bodies and interested groups.