A 14th century building has been fitted with a 21st century roof.

Blake Mews, a grade II listed property in Blake Street in the shadow of York Minster, has a green carpet crowning it, in the form of a sedum roof.

The roof has been fitted by property investment and development company The Helmsley Group.

Ian McAndrew, associate director at the Group, explained what a sedum roof is.

He said: "Living or green' roofs are growing in popularity and are increasingly being used on new buildings but this is the first time that we believe one has been used on residential properties within York city centre.

"A sedum roof is like a living carpet. Sedums are low-growing succulents - plants with thick fleshy leaves and stems - which makes them particularly suitable for growing in the inhospitable conditions found on a roof.

"A sedum roof benefits both those inhabiting the building, and the wider environment. Benefits include reduced heat loss from the building in winter, which reduces energy costs; improved acoustic performance of the building; the plants remove carbon dioxide and absorb pollutants from the air and protect the roof from UV light, so increasing its life span."

Blake Mews was originally a terrace of medieval houses built around a timber frame to which a brick façade was added in Georgian times.

The property was last occupied by household electrical retailer House & Son, which had a ground-floor showroom and living accommodation above, last used as offices. The business occupied the premises for almost a century before closing down three years ago.

The dilapidated showroom has now been upgraded to create two modern shop units, while the offices above have been turned back into living accommodation, in the form of two apartments.

Mr McAndrew added that the development had essentially been a conservation project although there have been difficulties in bringing a medieval building up to the standards required by modern building regulations.

He said: "It is a fascinating example of how modern building methods can be incorporated into an historic building.

"We are very privileged to be able to continue its 700-year architectural history."