Cleaning of Custom Cast Stone Masonry
During construction, prevention against staining
is mandatory and becomes the best solution for a clean finished
effort should be taken to protect the Cast Stone during storage,
setting, and after installation. Storage of Cast Stone should
be above ground on non-staining planks or pallets. The storage
site should be away from heavy construction traffic. Cast
Stone stored for an extended period of time should be kept
or non-staining tarpaulins. After setting, columns, pilasters,
entry jambs, window sills and all stone with projecting profiles
should be protected with non-staining material during the
Final Wash of Cast Stone
Regardless of the degree of care exercised during
construction, a final wash down will be needed and, normally, whatever
is specified to clean brickwork will adequately clean the Cast Stone.
A variety of commercial cleaners are available and most contain
detergents combined with mild solutions of phosphoric and/or muratic
acids. Special care may need to be taken when applying acidic cleaners
to areas where joints are left open or where sealant is used as
jointing material. The sealant manufacturer should be contacted
to ascertain compatibility with cleaning materials. Acid left behind
the stone in the masonry wythe may cause corrosion problems later
Common Stains on Cast Stone
The most common stains, due to construction, are dirt and mortar.
Dirt can be removed by scrubbing with a mild detergent and water.
Mortar stains require brushing a solution of one part hydrochloric
acid to six parts
water on the stain. Soak the stone with water prior to adding any
acid solution to prevent surface burning. Consult the brick supplier
applying acids to trim items. Insure that lower stone courses are
frequently drenched with water because as the acid is rinsed down
the wall, it can gather
strength when reapplied. Take necessary steps to protect windows,
door, and grade materials.
Unusual Stains on Cast Stone
When unusual stains are encountered, the same procedures which are
recommended to clean concrete will normally clean Cast Stone. The Portland
Cement Association publishes a guide for the removal of stains in concrete.
The most important step to stain removal is identifying the stain and its
cause. There are degreasers and paint removers readily available. Any treatment
should be tested on a small inconspicuous area prior to cleaning the main
Dunnage Material Stains
Dunnage materials used in the packing and transport of Cast Stone
can leave stains (or clean spots) after becoming wet. Wood packaging
products can transfer resins to the surface which may be easily removed.
dunnage made from fresh timber can cause dunnage marks which become
difficult to remove. Packing and dunnage materials should always
allow the exposed surfaces
to breathe, especially when stones are palletized or placed into
storage shortly after manufacture. This will avoid color differentials
due to moisture becoming
trapped on the surface of the stone. Power washing and sandblasting
are not recommended procedures for cleaning Cast Stone. Metal Fiber
Brushes are not
to be used for scrubbing Cast Stone.
Custom Cast Stone
734 East 169th Street • Westfield, Indiana 46074
Toll Free 888.776.9960 © Custom Cast