29/01/20
During a recent survey of a residential property, our Surveyor found a problem which affects many traditionally constructed buildings: cement mortar.
Historically, natural stone walls would have been pointed using lime mortar. However, we commonly find traditionally constructed buildings to have been repointed with cement mortar. The use of cement mortar in traditional construction is not recommended as cement sets very hard, often harder than the surrounding stonework and prevents minor movement in the building structure. This can result in the stonework cracking, spalling and becoming loose. Also, during wet weather, the stonework absorbs moisture. This moisture normally moves to the lime mortar joints where it evaporates. However, cement mortar acts as a ‘plug’ preventing the movement of moisture within the building fabric and during freezing weather, causes further damage to the stonework.
We recently encountered a particularly severe example which had resulted in significant erosion of the stonework, shown in the photos below. We recommended that the damaged stonework was replaced and that the cement mortar hacked out and pointed with softer lime mortar. If this cement mortar had been left, then further degradation and erosion would occur and eventually result in significant repair work.
If you think that you might have some issues with your stonework or pointing, please give us a call and one of our Building Surveyors will be delighted to offer their assistance.
Historically, natural stone walls would have been pointed using lime mortar. However, we commonly find traditionally constructed buildings to have been repointed with cement mortar. The use of cement mortar in traditional construction is not recommended as cement sets very hard, often harder than the surrounding stonework and prevents minor movement in the building structure. This can result in the stonework cracking, spalling and becoming loose. Also, during wet weather, the stonework absorbs moisture. This moisture normally moves to the lime mortar joints where it evaporates. However, cement mortar acts as a ‘plug’ preventing the movement of moisture within the building fabric and during freezing weather, causes further damage to the stonework.
We recently encountered a particularly severe example which had resulted in significant erosion of the stonework, shown in the photos below. We recommended that the damaged stonework was replaced and that the cement mortar hacked out and pointed with softer lime mortar. If this cement mortar had been left, then further degradation and erosion would occur and eventually result in significant repair work.
If you think that you might have some issues with your stonework or pointing, please give us a call and one of our Building Surveyors will be delighted to offer their assistance.