One of Orkney’s top visitor attractions is being threatened by the increasing numbers of tourists visiting it.
Built before before the Pyramids, Stonehenge or the Great Wall of China, Skara Brae is one of Europe’s finest examples of a Stone Age village, and has to be preserved according to Steve Watt, district architect with Historic Scotland..
He said that they had known for a long time that the treasure was a fragile monument, adding that detailed analysis had to be done to discover whether the walls were moving and being eroded.
Both Maeshowe and Skara Brae have particular issues we are looking at in-depth at the moment. Because people are walking on the wall heads we need to know if that is having an effect.”
Historic Scotland¹s scientists are particularly interested in house number seven, which had a glass roof fitted in the 1930s and reworked in the 1950s.
The sliding structure was put there to protect the structure, but may, in fact, prove to be causing its demise.
“It was the last to be excavated and was not exposed to the elements for very long. It was roofed very quickly and the stones had not been weathered like the other stones. Since that time we have noticed that the masonry inside house number seven seems to be suffering,” Mr Watt said.
He continued: “We were not sure if the glass was generating a heat build-up and damaging the structure. The stone furniture inside is made of fine slabs of Orkney flag and in some instances is only an inch thick.”
Skara Brae overlooks the Atlantic Ocean at the Bay of Skaill on Orkney’s West Mainland and, as such, is exposed to the elements, including the salt water.
Mr Watt explained: “All ground water has salts within it and especially when beside the sea. When the salt crystals form it is with an enormous force which can damage the stone.”
Skara Brae was engulfed and buried in sand until 1850, when during a severe storm and high tide, part of the cover was washed away exposing the stone walls of the Neolithic buildings.
A properly co-ordinated excavation did not take place until 1927 when an Australian, Professor Gordon Childe, began his careful research. The site consists of a group of ten stone houses, the walls of which are up to nine feet high. They are connected by a maze of stone-built passages and covered alleyways.
Inside, various articles of stone furniture have survived dressers, cupboards, box beds and seats.
The Stone Age inhabitants had primitive drainage systems, even water closets, 3,000 years before the Romans arrived in Britain.
To ensure its survival for another 1,000 years some intricate analysis is being carried out over the next six to 18 months.
“Small recording devices have been placed in house number seven to record information on temperature and relative humidity. It takes a reading once every minute. Every four months the information is downloaded and taken back to the Historic Scotland conservation centre. We are recording when the glass roof is open and shut. We have control data loggers in some of the other houses.”
Photogrammetry a process of measurement by photography is being used to tell whether the stones are moving or decreasing and if cracks are appearing.
“They put a series of small targets all over the walls and then an optically corrected photo is taken of each and every stone,” Mr Watt continued. “We do not know yet if they have moved. It will be six months before we know that.”
The scientists want to know if the writing in house number seven are being affected by the glass roof and have carried out an advanced technique of laser scanning to tell them if they are losing detail.
But it is a slow process and some parts of the analysis will take 18 months.
“We would certainly aim to keep it open to the public but we really need to understand the science going on. They really are unique buildings. The way they were built was incredible. An artificial mound was created then almost hollowed out for each house and lined with stone and the roof would span over the top.”
Mr Watt added: “Skara Brae could last another thousand years depending on what is done and how it is done. It is certainly not in imminent danger of collapse.”