Thorngreen lime kilns near Allenheads date back to the 19th Century
The use of "socks" that are made from a mesh fabric have been the key to help preserve some historic lime kilns.
Natural England is currently working to consolidate the remains of Thorngreen lime kilns near Allendale in Northumbrerland.
An assessment found that the iconic structure had large cracks in it.
In order to repair the cracks, while maintaining the original look of the building, the team decided on an unusual solution...grout filled socks.
The kilns are some of the largest and now best preserved in the area.
They had been badly damaged because the expansion and contraction of their walls, due to the cycle of heating and cooling in lime production, caused fissures to form.
Tom Gledhill, Natural England's Historic Environment Advisor for the North East, said: "One of the initial challenges at Thorngreen lime kiln was how to repair the cracks without damaging the outward appearance of this historic building."
Cintec Anchor System
Tom continued: "Due credit must go to a member of our conservation team, Paul Arkless of Blackett Ord Conservation Engineering, who identified an ingenious solution that used a series of mortar filled socks to pin the structure together."
This technique is known as the Cintec Anchor System and it uses a steel bar enclosed in a mesh fabric sock.
Holes are drilled at damaged parts of a structure and then the "socks" are pumped with a special type of grout to fill them.
The grout then expands with the sock moulding itself into the spaces within the walls.
Once the preservation of the kilns is complete it is hoped it will provide better access to visitors to Thorngreen.