Troubleshooting Guide - Lime Mortar smeared over masonry/brick
Possible causes of smeared Lime Mortar over masonry/brick
- Unskilled or hurried application of pointing can lead to mortar being deposited on the face of the masonry/brick. This is a particular problem when the masonry/brick is porous as it will absorb the lime into its fabric and will be harder to remove.
- Sponge finishing of pointing to reveal aggregate, if done when the pointing is too wet or done hurriedly, can cause lime to be deposited over the face of the wall. A thin layer of lime when wet will not be visible however it will dry white. This is a particular problem when the masonry/brick is porous as it will absorb the lime into its fabric and will be harder to remove.
If masonry/brick is being rendered or limewashed/painted over: excess can just be scraped off with a trowel.
If masonry/brick is to be left exposed: If smearing is noted during the application of the mortar remove immediately with a clean trowel, any remnants can then be removed using a wire brush. Do not introduce water as this can make the situation worse by spreading the lime even further. If the problem has been caused by overzealous sponging of pointing and the lime has dried on the face of the masonry/brick, then first try removing by vigorously wire brushing it. If this does not work then a weak acid (diluted brick acid) can be used CAREFULLY and SPARINGLY to attack the lime on the masonry/brick. Please note that every care should be taken not to allow the acid to come into contact with the mortar joints themselves as they will react with the acid and consequently will be damaged.
As a last resort, a specialist conservation cleaning company using low-pressure TORC methods can be employed.
Ty Mawr does provide an on-site supervision and an advice service that can be requested.