Exterior Limestone Cleaning

Some Limestone’s weather endurance qualities are well-known and respected, and its resistance to damage from the common accumulation of dirt and soil carried in urban atmospheres has been proved through years of use in all types of buildings.

There are, however, a number of factors which may tend to create unsightly blemishes on the stone’s visible surfaces. Most of the blemishes have no structural effect on the stone. Some will increase in intensity as the conditions causing them remain uncorrected. Natural characteristics and variations normal to the stone are sometimes mistaken for blemishes.

Not all buildings will clean up so easily, and different areas of the same building may require different treatment. Contact with soil is of even greater concern. All stones will absorb moisture to some degree, and depending on the chemistry of the soil, they may also wick staining agents up from the soil. If contact with grade is unavoidable, a rock filled trench drain may be required as it will keep the face of the stone free from the constantly moist soil condition.

Limestones have varying porosities , and some can be quite high. Despite the availability of modern high-performance impregnators (sealers), the stain resistance of the higher porosity varieties of limestone may be less than that desired. Limestones are based on a building block of calcium carbonate, which is attacked by relatively mild acidic solutions. This stone type would require significantly more care and maintenance attention than other varieties of stone.

Marble Renewal can help homeowners, architects, builders, masons, building owners and other interested parties examine the causes, prevention and removal of the most common blemishes, dirt and stains. Specific conditions, which usually are local in occurrence, often may be treated by our experienced personnel with specialized treatment. The top photo is before cleaning while the bottom photo is post treatment.