Masonry

Mortar for Repointing

The mortar joints in masonry fasten the stones or bricks together into a structural whole and make a binding, watertight seal. When mortar deteriorates and decays, it must be replaced to restore the masonry’s structural integrity and appearance. This replacement process is called repointing. If you have decided to take on the repointing job yourself, your first task should be to decide what type of mortar mix to use.

Mix Ingredients

Inspection for Masonry Problems

Proper maintenance and regular inspections are the best way to prolong the life of a masonry building, be it of limestone, granite, brick, marble or sandstone. Inspection should begin with the building’s site; environment, terrain and vegetation are the 3 areas to look at.

Environment

Masonry Deterioration

Sandstone DecayStone and brick are assailed by multiple forces over time, and the extent of a structure’s resistance to them is dependent on how well designed it is.

A robustly built building may be able to bear up indefinitely against such forces, while a structure with a bad foundation, which does not shed water well, absorb movements and expansions, or is made from shoddy materials, will quickly deteriorate and require maintenance.

Most Common Causes of Masonry Deterioration

    1. Excess moisture in masonry that leads to damaging freeze/thaw cycles and soluble salt crystallization action.

Cleaning Masonry Buildings

Cleaning Masonry with SandblastingOver time, brick and stone buildings weather and age, and often new owners decide to clean them up to make them appear newer. I happen to prefer the rich, soft colors and patina of naturally aged stone. By removing all signs of aging, they also end up not only removing much of it’s character, but also speed up further deterioration through harsh chemical cleaning or sandblasting.

On the other hand, there are cases when cleaning masonry is warranted. If you have good reason to suspect that the masonry is being damaged by pollutants, dirt paint or stains on it’s surface, cleaning should be done in order to preserve the stone and mortar surface.

Masonry Spalling

Spalling is a form of masonry deterioration in which the outer section of a stone, brick or mortar breaks away in a localized area. The term spalling sometimes can be a general one, refering to any type of coming away of the surface, such as exfoliation or delamination.

The cause can be either freezing and thawing cycles of moisture trapped within the masonry or salt crystal pressures. Another cause is mortar of excessive hardness. Any movement in the wall, from settlement, thermal expansion, or vibration, is deflected by the mortar, instead of being absorbed by it. This pressure then transmits back to the masonry, ultimately leading to spalling.