Some storefronts are constructed of brick or stone, and like their
metal and wooden counterparts, also may have been subjected to
physical damage or alterations over time. Although mortar may
have disintegrated, inappropriate surface coatings applied, and
openings reduced or blocked up, careful rehabilitation will help
restore the visual and physical integrity of the masonry storefront.
Repair and Replacement of Masonry
If obvious signs of deterioration--disintegrating mortar, spalling
bricks or stone--are present, the causes (ground moisture, leaky
downspouts, etc.) should be identified and corrected. Some repointing
may be necessary on the masonry surface, but should be limited
to areas in which so much mortar is missing that water accumulates
in the mortar joints, causing further deterioration. New mortar
should duplicate the composition, color, texture, and hardness,
as well as the joint size and profile of the original. Badly spalling
bricks may have to be replaced. Deteriorated stone may be replaced
in kind, or with a matching substitute material; in some cases
where not visually prominent, it may be covered with stucco, possibly
scored to resemble blocks of stone.
Cleaning Masonry
Inappropriate cleaning techniques can be a major source of damage
to historic masonry buildings. Historic masonry should be cleaned
only when necessary to halt deterioration or to remove graffiti
and stains, and always with the gentlest means possible, such
as water and a mild detergent using natural bristle brushes, and/or
a non-harmful chemical solution, both followed by a low-pressure
water rinse.
It is important to remember that many mid-19th century brick buildings
were painted immediately or soon after construction to protect
poor quality brick or to imitate stone. Some historic masonry
buildings not originally painted were painted at a later date
to hide alterations or repairs, or to solve recurring maintenance
or moisture problems. Thus, whether for reasons of historical
tradition or practicality, it may be preferable to retain existing
paint. If it is readily apparent that paint is not historic and
is a later, perhaps unsightly or inappropriate treatment, removal
may be attempted, but only if this can be carried out without
damaging the historic masonry. Generally, paint removal from historic
masonry may be accomplished successfully only with the use of
specially formulated chemical paint removers. No abrasive techniques,
such as wet or dry sandblasting should be considered. If nonhistoric
paint cannot be removed without using abrasive methods, it is
best to leave the masonry painted, although repainting in a compatible
color may help visually.
Removing unsightly mastic from masonry presents a similarly serious
problem. Its removal by mechanical means may result in abrading
the masonry, and chemical and heat methods may prove ineffective,
although solvents like acetone will aid in softening the hardened
mastic. If the mastic has become brittle, a flat chisel may be
used to pop it off; but this technique, if not undertaken with
care, may result in damaging the masonry. And even if total removal
is possible, the mastic may have permanently stained the masonry.
Replacement of these masonry sections marred by mastic application
may be one option in limited situations; individual pieces of
stone or bricks that have been damaged by inappropriate alterations
may be cut out and replaced with new pieces that duplicate the
original. However, since an exact match will be nearly impossible
to achieve, it may be necessary to paint the repaired masonry
in order to create a harmonious facade. Replacement of a large
area with new materials may not be acceptable as it may give the
building a new, nonhistoric appearance inappropriate to the building
style and period.
"Rehabilitating Historic Storefronts" an Historic Preservation Brief
