Bradford Civic Society has objected to plans for significant alterations to the facade of a 1960s city landmark with a surprising history.

Arndale House was the only building in the UK to have been designed by the architects’s firm behind Seattle’s Space Needle – John Graham and Partners – and has been highlighted as a positive example of understated design of the era.

Now the 20th Century Society – which campaigns to retain and protect buildings that are good examples of 20th Century architecture – has joined the Civic Society and raised concerns about the proposals for the building.

In response to the new application, the group has written to Bradford Council, saying: “Arndale House is an important Brutalist office building designed by a major, internationally-known American architectural practice.

“It is therefore considered a Non-Designated Heritage Asset of great significance.

“While the Society welcomes the conversion of offices for residential use, we are concerned about the current proposals.

“We believe the proposed removal of the office’s existing windows and their replacement with double-glazed openable UPVC units will cause substantial harm to a valuable NDHA.

“Arndale House is characterised by its regular pattern of single-paned and seemingly frameless windows.

“This appearance would be completely altered if the proposed windows were installed which have grey frames and are split into three panels.

“This proposal would not just harm the building’s aesthetic value but would involve the removal of much architecturally and historically significant primary fabric.

“The Society encourages the applicant to consider secondary glazing which will improve the energy efficiency of the windows without the need to replace original fabric.

“The Society strongly objects to the proposed changes to Arndale House’s windows which will cause substantial harm to an important Non-Designated Heritage Asset.”

Bradford Council’s own Design and Conservation officer, Hannah Meekings, has also voiced concerns.

In her report on the proposals, she said: “I have concerns about the visual impact of the proposed windows. The existing windows are, as far I can tell, original. They comprise of a single pane of glass and have a minimal frame (possibly metal edged) which is deeply recessed into the reveals. In my opinion, UPVC is not an appropriate material for the proposed frames and the manner in which the window has been subdivided and the incorporation of plastic inserts at the top and bottom will result in a significant visual impact which will be detrimental to the simplistic intended appearance of the building of which it’s fenestration is an important contributing element.

A decision on the application is expected in the New Year.

Extracts of this report have been taken from original reporting in the Bradford Telegraph and Argus.