This is a big problem in old buildings: providing universal access without ruining the look of the building.

While visiting Edinburgh recently I wondered how people in wheelchairs could cope in a city where almost every old building seemed to have stairs to the front door. It is a problem with many historic buildings in North America, where historic preservationists worry about how ramps and lifts don't really fit architecturally.

Now Designboom shows us a remarkable solution: crazy wonderful disappearing stairs from Sesame Access in the UK. They were invented by engineer Charlie Lyons, who "was in a pub with his friend, and his friend complained how his wife had problems accessing buildings because she was a wheelchair user. Charlie loves the challenge of inventing, and set about to find a solution to the problem." He built his first set in 1996 and it is still going strong.

There are a number of different varieties and most are almost invisible. This is a big deal in heritage buildings, and "English Heritage has approved them in many Grade I, II and II buildings throughout the UK." Installations include Kensington Palace, UK Supreme Court, Apple stores and France and Germany, Sotheby’s in Paris, Oxford and Cambridge Universities, Tate Britain and The Barbican Centre; I have probably walked by some of them without even noticing.

The thing that really sets us apart from the crowd is the way we fully integrate our lifts into the very fabric of a building, to make them almost invisible. They can be clad with whatever material our client needs, and they represent the very highest standard of British engineering.

These are all custom-made and no doubt very expensive, but what a great solution to a difficult problem; we like to say that the greenest building is the one already standing, but they have to adapt to be accessible to everyone. More at Sesame Access.