Earlier this year we were awarded a tendered project to stabilise a brickwork wall. Over time, the wall had become part of the extended grounds of a Grade II Listed Building. The ground had been levelled and trees had reclaimed the land. The roots and pressure from the ground behind had affected the wall. Somewhat typical of historic walls that have become retaining, these were not initially constructed with this in mind.
Housing estates now surrounded the plot and action was required to be taken in order to preserve the existing environment. A structural engineering project was formed to install reverse buttresses, reducing the wall and ground level.
Initially, the condition of the trees were assessed to permit access to undertake the works – which included roots and branches loadings. Those affected by the works could have potential for the trees to overturn, creating a hazard for operatives and those in the surrounding area.
Access with surrounding properties was a challenge for the level of works required. Temporary timber supports were formed to support the wall during the project.
With an excavator, the ground level was reduced, being regraded from behind the wall. Four footings were excavated for the buttress foundations. These were shored with timber and rebar fitted, including stainless steel rods through the wall. The stainless-steel fixings would be tightened as the concrete cured.
The concrete was pumped to the location, being poured in four sections in order to prevent overloading the wall in one visit.
As the concrete cured, we began the process of taking the wall down to the new height. This involved masonry repairs and the rebuilding of sections. The cementitious mortar (causing moisture to be held) was replaced with a lime mix along the face of the boundary wall.
The Conservation Officer approved a gritty lime-based mix with red brick dust for the coloured finish to the red brick. Once the lime was ready to be brushed back, this exposed the grit which is both aesthetically pleasing and increases resilience to weathering.
An existing historic boundary stone – which had been covered by overgrown vegetation – was brought to our attention by a resident. This was incorporated within the rebuild in the same vicinity. The new low-level wall was then completed with an estate rail fence to reduce fall risk.
