English: Rosedowns Ferro Concrete Workshop, Hull. The De Smet Rosedown's concrete workshop at the junction of Caroline Street and Cannon Street is a Grade II Listed building and is said to be either the oldest or second oldest surviving building of its kind in Britain. Developed in France, the pioneering Hennebique system used here had enabled the erection of entire reinforced concrete framed buildings and was patented in 1897. Reinforced concrete had been developed in the 1850s but was previously only used for flat structures such as floors and roofs. Reports on conservation issues surrounding the Rosedowns workshop seem to suggest it is one of only two surviving Hennebique buildings in Britain, the other being a mill in Swansea, but this is misleading to say the least. The Royal Liver Building in Liverpool [1] is constructed from reinforced concrete and was designed and built by Louis Gustave Mouchel who had arrived in the UK in 1897 with a license to use Hennebique's methods. The CWS Flour Mills in Avonmouth [2] is almost certainly another example of the same type of building and I think it quite likely there are many others. The Hull building would seem to be an early example, having been built by the firm's own workers in 1900. Rose Downs & Thompson put up the building as a workshop for the manufacture of machinery used in the edible oil industry, an industry they developed on the site of an old iron foundry and one which continues in Hull to this day. The building has been disused since around 1996 and although said to be very robust and deteriorating only slowly, where reinforcing bars are close to the surface of the concrete they are rusting and forcing fragments of concrete to fall off. Netting has been erected on the front of the building to protect the passing public. In 2003 an application for Listed Building Consent to demolish the workshop was submitted and the owners said the building was a maintenance liability. The application was refused. The building is on the Listed Buildings at Risk Register but all attempts to find a use for it have proved unsuccessful. It seems unlikely that this unattractive lump of a building would have survived long enough to earn listed building status and a blue heritage plaque had it not been almost indestructible.