Client
E Bowman & Sons Ltd & English Heritage
Location
Hardwick Hall, Derbyshire
Overview
A National Trust, Tudor property - one of Britain’s most complete Elizabethan houses. The works are part of a £6 million re-development project funded by National Trust, The Heritage Lottery Fund and English Heritage. The project has supported essential maintenance and repair works to the hall, buildings and surrounding estate.
Problem
Over the years, areas of stone boundary walling had reached a stage where it required renovation and stabilisation of the stone/rubble-fill construction to protect it for the future.
TBL Solution
TBL adopted a combination of Thor Helical remedial grout-ties to tie both faces of the stonework through the internal rubble fill, and a system of gravity-fed grout using CMS Pozament Tarmac’s Limelite Heritage Grout to stabilise and void-fill the internal core.
To keep the repairs sympathetic to the structure, we had to adopt a cautious and delicate approach. All drilling for the grout ties was done with the use of diamond drills of a carefully selected cutting matrix to avoid any vibration and potential damage to the wall. Following installation of the grout ties, the holes were reinstated with lime-mix pointing to blend in with the surrounding bed joints, or a stone-dust mix (saved from the drilling), where wall ties were installed into facing masonry.
TBL operates various systems of masonry grouting. With this particular job it was necessary to use a gravity-fed system using hopper tanks and feed tubes rather than a pumped system – again to avoid damage to the historic wall. The gravity-fed grouting of the wall was done in carefully monitored sections and lifts, to avoid overloading the structure until the grout had gelled and further filling could progress.
Benefit
We were able to successfully provide a sympathetic system of reinstating stability to the historic boundary wall, using the most economic and least disruptive methods. The remedial scheme had no visual impact on the wall and our works were virtually invisible on completion.
