Listed Building Consent is required for any repointing work which affects the character of the particular Listed Building, e.g. any change in mortar mix, style of pointing, or method of both preparing the brickwork and carrying out the work.  Consent is also required for extensive amounts of repointing, for example where whole elevations are being repointed.

The reasons for this control are not merely that changes in pointing affect the aesthetics of the building; such changes can also severely damage and undermine the structural and environmental performance of the building, and cause serious maintenance problems in the future.

Generally repointing should not extend beyond the area where it is necessary, and surviving historic pointing should be preserved.

Mortar Mix

Historic brickwork was always laid with lime mortar, and any pointing or repointing work carried out before the end of the 19th Century would have been carried out in lime mortar as well.

Lime mortar has many crucial advantages over cement based mixes in work to historic brickwork;

• Lime mortars are porous, and allow water in the structure to escape through evaporation.
• Lime is a softer material than the brickwork it adjoins, so decay through waterbourne salts is concentrated in the replaceable mortar rather than in the more precious bricks.
• Lime mortar is a flexible material that can absorb the movement of historic structures without cracking.

Pointing Styles

Historic brickwork would usually have been pointed with a flush joint, and this style should normally be used in any repointing work. However, care should be taken to ensure that there is no ‘buttering’ over of the brick arrises; not only does this widen the visual mortar joint and have a considerable impact on the character and appearance of the building as a whole, but also it creates weak ‘feather edges’ behind which damp can enter. Where brickwork is particularly irregular or decayed, the mortar should usually sit slightly recessed, leaving the arrises exposed.

Where more elaborate pointing styles are evident, such as tuck pointing, scribed joints, or galleted mortar, care should be taken to ensure that any repointing work matches the original.

Modern styles of pointing such as weatherstruck are rarely suitable for repointing historic brickwork due to their characteristic appearance of hard shadow lines.

Cleaning Out Joints

It is usually sufficient to rake out deteriorated mortar from a joint, but where cutting out is required, this should only be with specialist chisels and, exceptionally, with masonry saws and drills. Cutting out should never be with mechanical disc cutters, since it may increase the width of the joints, and there is a high risk of over-running and scoring the brickwork.

Useful Contacts

Suppliers of lime putty will be happy to offer advice about the suitability of different lime products available, many advertise in the Building Conservation Directory, which also publishes articles on all aspects of historic building conservation, accessible at the Building Conservation website.

If you require any further general advice about listed buildings or conservation areas please contact our Planning Enquiries Team on 01233 330264 or contact us via email. 

For detailed advice on works to particular listed buildings please contact one of the Conservation Officers on either 01233 330729 or 01233 330739.