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.
Note the general climate conditions; average yearly temperature ranges, prevailing wind speed and direction, humidity and snow accumulation levels. Any extreme conditions will surely be associated with masonry cracking, efflorescence and spalling.
Frostline and number freeze-thaw cycles in cold climates also are a concern. Is the building located near enough to a body of seawater to cause additional efflorescence? Any acid rain in the region or industrial pollution can cause damage to limestone, marble and sandstone buildings.
Check proximity to major roadways or railways; mortar joints are prone to vibration damage. Any major excavation in the near vicinity, such as subways, deep foundations for skyscrapers, or underground sewage systems may lower water tables and cause soil problems and eventual failure of foundations. Sun and wind exposure will affect moisture evaporation and penetration of rain.
Terrain and Vegetation
Determine the type of soil; different soils drain moisture differently, and poor soil drainage can lead to structural damage. Drainage of the surface surrounding the house is also important; it should slope downward fro the structure.
If no slope exists around the building, water will puddle during heavy rainfall and cause structural problems. Check for soil, gravel or asphalt covering part of a masonry wall, this can cause moisture penetration.
Certain tree species can dry clay soils if they are within 50 feet of the building- elms and poplars. Ivy and other creeping species can penetrate and damage mortar joints, also their leaves make drying of porous masonry materials difficult.
Moving on to the overall condition of the building, note the general state of repair. Is there any evidence of a fire or flooding, signs of settlement such as cracking in walls or foundations, or settlement of vertical walls such as mortar cracking?
Determine the condition of the roofing; leaking roofs will cause stains on highest parts of the walls and masonry damage. Condition of gutters, downspouts and flashing will also affect moisture accumulation and penetration levels.
A good basement inspection will ensure good drainage, foundation wall condition and damp-proofing of walls. Interior spaces like bathrooms and kitchens can be sources of moisture from inside the house; look for cracking plaster and stains on walls.
Finally, the masonry itself can be inspected. Start by noting the composition of the materials. Material type, texture and other characteristics point toward vulnerability to damage. Are replaced bricks or stones matched to the original structure?
Missing brick or stone can allow water penetration. Any fine molding or carving can require specialized work if renovation is needed, but staining or dirt marks usually are not indicative of a serious problem other than a need of cleaning.
Bulges in wall structure mean the wall has moved and may need to be repaired. Cracking also indicates some type of movement. Smaller cracks are patchable but larger ones may necessitate reconstruction of the area. An enlarging crack points to an active problem which will get worse, and underlying problems need to be addressed before repairing the crack.
Efflorescence is a white staining deposit which indicates excess moisture. On new or newly repointed walls, it is temporary and not a problem. Any water penetration of masonry joints or brick will lead to further structural deterioration.
Paint on masonry should be breathable so that moisture is not trapped within the stone or brick. If the paint is flaking, peeling or blistering, then the paint may not be breathable.
Determine mortar type. Cement based mortar is grayish and hard, it too hard for use in older masonry, leading to damage. Another indication of mortar which is excessively hard is brick or stone with chipped or broken edges adjacent to joints. Lime based mortar is whitish in color. Check for missing, crumbling or eroding mortar in need of repointing.