Stonework on the early 15th century Hylton Castle gatehouse tower, which displays fine examples of royal heraldry including Richard II’s White Hart badge, has suffered damage from hundreds of years of driving rain, snow and wind.
Now specialised work using high-tech scanning equipment is taking place to measure the rate of decay on the highly decorative gatehouse-tower built by the wealthy Sir William Hylton, and find the best way of stopping it.
Stuart Chadwick, senior laser scanning surveyor with laser scanning specialists Greenhatch, travelled up to Wearside to carry out the scanning.
“The scanner actually revolves as it moves over the surface of the stonework, and as it turns it fires lasers in all directions taking measurements at a speed of 500,000 points a second. When it has done a full sweep you get a three-dimensional image.”
The ‘point cloud’ image of the surface is made up of hundreds of measurements taken just half a millimetre apart, and from this highly detailed measurement 3-D meshed models and elevations can be produced.
It’s a method of scanning that can show up the very small changes that have taken place over a much shorter space of time - rather than the serious deterioration that can be seen by the human eye.
“From this information we see what erosion is happening before it’s actually visible and decide what needs to be done to arrest it and preserve this valuable stonework,” explained, Ray Stockdale, works manager for English Heritage in the North East.
Committed to the long-term conservation of Hylton Castle English Heritage is using the new technology allied to age-old craft skills to help the carvings remain as a very visual display of the wealth and status of one of the north’s great families.
Find out more about Hylton Castle on the English Heritage website
