Historic Preservation - Technical Procedures
Cleaning Interior Limestone Walls
Hsr - Departmental Auditorium Bldg/Wash, Dc - Grier, Brown..
Cleaning Interior Limestone Walls
CLEANING INTERIOR LIMESTONE WALLS
THE CLEANING OR REMOVAL OF STAINS FROM STONE MAY INVOLVE THE USE
OF LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON ADJACENT
MATERIAL, DISCOLOR THE STONE OR DRIVE THE STAINS DEEPER INTO POROUS
STONES. USE THE PRODUCTS AND TECHNIQUES DESCRIBED HERE ONLY FOR
THE COMBINATIONS OF DIRT/STAIN AND STONE SPECIFIED.
A. This procedure includes guidance on surface dirt from
interior limestone walls. GENERALLY, THIS WORK SHOULD BE
PERFORMED BY AN EXPERIENCED CONTRACTOR.
B. See 01100-07-S for general project guidelines to be
reviewed along with this procedure. These guidelines
cover the following sections:
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. General Protection (Surface and Surrounding)
These guidelines should be reviewed prior to performing
this procedure and should be followed, when applicable,
along with recommendations from the Regional Historic
Preservation Officer (RHPO).
C. For precautions relating to pressure washing, see 04510-04-S.
A. NOVA Chemical Company
1520 Erie North
Kansas City, MO 64116
B. ProSoCo, Inc.
755 Minnesota Avenue
P.O. Box 1578
Kansas City, KS 66117
800/255-4255 or 913/281-2700
A. Limestone Cleaner: Mildly acidic cleaner diluted with
two parts water and containing 5 parts per million (ppm)
of hydrochloric acid, 1 mg/m3 oxalic acid, 25 ppm glycol
ether, and 10 mg/m3 ethylene glycol such as "Interior
Stone Cleaner" (ProSoCo, Inc.), or approved equal.
B. Varnish and Paint Remover: Solvent based methylene
chloride stripper specifically formulated for removing
paint and adhesives from masonry such as "Graffiti
Remover" (NOVA Chemical Company), "Sure Klean Graffiti
Remover" (ProSoCo, Inc.), or approved equal.
C. Clean, potable water (heated to a temperature effective
and tested for cleaning procedure and approved by RHPO).
D. Clean, soft cloths
A. Pressure water rinsing equipment (measuring between 100
and 400 psi for low-pressure; between 400 and 800 psi for
B. Fan-type spray tips (15 degree fan spray)
C. Polyethylene bucket
D. Soft, fiber bristle brushes
A. Test clean a small, inconspicuous area to check for
adverse effects and damage to the material.
1. Protect surrounding materials on the site and
adjacent building surfaces from coming in contact
with the cleaning materials and run-off.
2. Provide workers with necessary protection against
cleaning chemicals, overspray and run-off.
3. Prevent cleaning chemicals from coming in contact
with any painted, polished or metallic surfaces.
4. Divert and contain flow of run-off in compliance
with municipal codes so as not to damage
surrounding materials. Comply with municipal codes
regarding containment and disposal of cleaning
B. Surface Preparation:
1. Before proceeding with cleaning operations, remove
all miscellaneous hardware from the surface to
prevent any discoloration.
2. Clean the limestone working from bottom to top.
3.03 ERECTION, INSTALLATION, APPLICATION
NOTE: WHEN CLEANING, AVOID OVERCLEANING. AIM FOR ACHIEVING
85% CLEAN. MOST DAMAGE OCCURS WHEN ATTEMPTING TO CLEAN THE
NOTE: TEST CLEAN A SMALL AREA TO DETERMINE EFFECTIVENESS OF
CLEANING METHODS, MATERIALS, EQUIPMENT AND WORKING PRESSURES
SELECTED BEFORE PROCEEDING WITH CLEANING OPERATIONS ON LARGER
AREAS. ADJUST METHODS, MATERIALS, EQUIPMENT, PRESSURES, ETC.
AS NECESSARY. DO NOT PROCEED UNTIL AN ACCEPTABLE CLEANING
OPERATION HAS BEEN APPROVED AND FULLY DOCUMENTED.
A. Dilute limestone cleaner with water (in accordance with
results of test cleaning) and mix solution in a
B. Pre-wet limestone surface using a low pressure warm water
wash (between 100-400 psi).
C. Apply limestone cleaner to limestone using a soft, fiber
bristle brush. Allow to stand for 3-5 minutes or as
determined by testing.
D. Apply more cleaner while lightly brushing stained areas
with a soft, fiber bristle brush. Continue to scrub the
surface for length of time as determined by testing.
E. Thoroughly rinse the surface using a low pressure warm
1. Rinse all corners, moldings, and interstices to
remove all traces of chemical without damaging
2. Heat rinse water to a temperature determined most
effective during testing.
F. Use sponges and clean, soft cloths to remove excess water
from the surface of the limestone; allow the surface to
G. To remove paint or adhesives that may remain on the
surface, apply a varnish or paint remover following
END OF SECTION