B and M Builders are specialists in listed building renovations. We have the experience and knowledge to carry out work on listed buildings in a sensitive manner. We are members of the Federation of Master Builders and are proud to preserve and practice many traditional building techniques.

We understand the challenges of working on listed buildings and of undertaking conservation work on historic structures. In particular we have a lot of experience working with lime mortars and renders.

Lime Mortaring

Many buildings built before the Victorian era use lime mortaring rather than cement to secure bricks and masonry.  Lime mortaring is more forgiving of soft masonry than modern cements and allows the masonry to move and settle slightly over time. It is also much more effective at shedding water than modern cements, reducing the amount of damage from freezing and thawing in winter.

As with modern cement, lime mortaring does need to be replaced over time. Using modern cements to repair buildings that were originally constructed using lime mortars can cause serious damage to the masonry. The accepted method for repairing lime mortaring is to work from the top down on buildings. We will carefully remove any damaged mortar and replace it with newly mixed lime mortar. This needs to be allowed to partially dry for a number of hours with the exact time varying depending on the weather conditions. Once the lime mortar has begun to set it can then be dressed and finished.

Lime Plastering

As well as using lime to secure masonry many traditional buildings have a lime render or plaster finish. Lime rendering can be applied to rough, uneven surfaces and so is often used on older buildings with rubble masonry construction.

A properly applied lime render adds a protective layer with the lime absorbing moisture rather than letting it through to the underlying structure. Lime plastering can also be used on the interior of buildings to provide a smooth finish. A range of finishes can be put onto lime render and plaster so that it matches with the rest of your structure.