Abbeyfields Case Study
During construction in 1862, the builder had serious financial problems , and his efforts to save money resulted in many defects despite the grand appearance. The structure is of poor quality soft red brick, badly laid in places, faced with knapped flint, stone and rubbed brick. The facings are not adequately tied to the structure and rely on the mortar and the occasional long flint turned into the br ickwork. The mortar was mixed with soot to colour it black and has denatured badly over the years. Many of the flints have become detached as a result. The stone dressings are actually triangular in plan and are not tied to the structure.
As it looked in danger of collapse, I arranged for shoring and fencing and requested further investigations and the services of a structural engineer.
On agreement with the client, I consulted a structural engineer who is experienced in works to historic buildings. After their initial assessment confirming that the stonework was unstable, I arranged a meeting between the client, and the Conservation Officer to request removal of the internal joinery and part of the floor covering for further assessments of the structure.
I arranged for the joinery removals to be carried out by experienced building contractors who do a great deal of work on historic buildings. I photographed the whole turret internally and externally before work commenced, and specifed that all the joinery must be numbered as it was taken off and stored on site to avoid loss or damage in transit.
After the joinery was removed, I discovered that there were cast iron columns on spreaders behind the mullions of the ground floor, which were badly corroded. As a result, the iron had expanded, and was pushing the stonework outwards. On top of the columns, behind the transoms, there was a wrought iron strap, again corroded, with loose anchor points in the brickwork either side of the turret. Water was entering the cracks in the stonework and soaking the brick plinth as well as causing more corrosion. The brick plinth was badly eroded so that the columns did not have a firm base to sit on.
The movement was so advanced that there was a danger that the stone would fall out, hazardous for the occupants and destructive to the historic fabric. I decided there was no other option but to dismantle the ground floor stone and brick masonry, to enable replacement of the iron with stainless steel.
The Conservation Officer confirmed that listed building consent would be required so I prepared an application. Time was of the essence and the Conservation officer said she would condition items such as new stone and brick, without the need to submit samples first.
Based on all the information, I prepared a schedule of works. I put in a clause that any replacement of historic material must be agreed with me first and a reassessment of the stone dressings must be made once they were removed. Nothing must be removed from the site to avoid loss or damage. I put in a contingency sum to account for unknown repairs, always an issue with existing buildings and an unknown quantity until work starts.
Listed building consent was granted in time for works to begin. After the removals were complete, I inspected the stone and brickwork again. There was little damage apart from the cracks seen at the survey stage, and no wholesale replacement was necessary.
The foreman happened to be an experienced bricklayer who had carried out stone repairs in the past, so I asked for a sample repair to be carried out on a section of mullion. This proved satisfactory, so I confirmed he could continue. I agreed a suitable brick as replacements for the damp damaged internal face of the plinth. The column bases had to have a sound structure to support them and the existing brickwork was too friable. There was no damp proof course in the plinth of the turret, although there was a slate one elsewhere, so I specified an injected DPC, which was taken up well by the porous clay bricks.
The new stainless steel columns and strap were installed and the stone and brickwork reinstated, using a lime putty mixed with silver sand to keep the joints as narrow as originally designed. Stainless steel cramps and dowels replaced the iron to avoid rusting causing problems in the future.
The joinery was reinstated according to the numbers and my photographs, and I asked for small holes to be drilled top and bottom, into parts of the patterning so it would not show, to give ventilation behind it to prevent rot, and to remove any residual damp from the brickwork.
As works progressed, I photographed before each new removal in accordance with the listed building consent conditions.
Regular meetings were held with the client and the Conservation Officer to keep all informed of progress.
The whole was reinstated with minimal loss of original fabric. Repairs were not obvious in the finished work.