. REPAIRING PERISHED MORTAR JOINTS
Over long periods of time and prolonged exposure to the weather, mortar joints begin to deteriorate. This is more prevalent on old walls or buildings, which are likely to have been constructed with softer lime mortar and/or weaker mortar mixes. With successive winters, the mortar begins to succumb to the actions of frost, which causes the front of the joints to crumble and fall away. If left unattended, the mortar joints can deteriorate to the point where rain
penetration through the wall becomes an issue, as does the risk of structural failure.
Fig. 269 Perished mortar joints.