U.S. General Services Administration
Technical Procedures Disclaimer
Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.
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We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.
PART 1–GENERAL 1.01 SUMMARY
A. This procedure includes guidance on removing climbing plants from masonry.
B. It is important to remove heavy vegetative growth from masonry, as its presence can pose many problems, such as holding moisture against the masonry surface, blocking gutters and downspouts, scouring soft wall surfaces, eroding mortar and hindering or limiting access for maintenance inspections and repairs.
C. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
- Safety Precautions
- Historic Structures Precautions
- Submittals
- Quality Assurance
- Delivery, Storage and Handling
- Project/Site Conditions
- Sequencing and Scheduling
- 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).
PART 2–PRODUCTS
2.01 MANUFACTURERS
A. Chevron Chemical Co. Ortho Consumer Products Division
P.O. Box 5047
San Romon, CA 94583-0947
510/842-1000
B. Monsanto Co.
Agricultural Products
St. Louis, MO 63167
800/225-2883 or 314/694-1000
2.02 MATERIALS
A. Ammonium Sulfamate: (crystals)
CAUTION: THE USE OF AMMONIUM SULFAMATE MAY BE DEPENDENT UPON REGIONAL, STATE OR LOCAL RESTRICTIONS. ENVIRONMENTAL CONDITIONS AND APPROPRIATENESS SHOULD BE REVIEWED.
- Past use was a base for weed killers; Not now readily available; Substitute any brand weed killer solution.
- Available from chemical supply house, construction specialties distributor, garden and lawn supply center.
-OR-
B. A commercial weed killer such as “Brush-B-Gon” (Chevron Chemical Co.), “Round-Up” (Monsanto Co.), or approved equal.
NOTE: CONSULT WITH RHPO ABOUT SELECTION OF WEED KILLER TO AVOID USING ONE WHICH MIGHT DAMAGE THE MASONRY. FOLLOW MANUFACTURERS INSTRUCTIONS.
2.03 EQUIPMENT
A. Lopping and/or pruning shears
B. Garden hose and nozzle
C. Stiff bristle brushes (non-metallic)
D. Wood scrapers, knife blades and spatulas
PART 3–EXECUTION
3.01 EXAMINATION
A. Inspect building at the beginning of the growing season and monthly during the growing season for signs of change in drainage patterns and evidence of plant material damaging the building.
B. Examine the wall surface to determine the amount of damage being caused by the presence of the plant growth.
C. Check to see if the vine roots have penetrated the mortar joints.
D. Notify the RHPO if mortar joints, or the masonry units themselves, are found to be deteriorated due to the roots, or to the weight of the plant growth.
3.02 ERECTION, INSTALLATION, APPLICATION
A. Using loping or pruning shears, cut vine trunk(s) about four inches (4”) above grade and remove a section of stem above this cut. Leave approximately a six inch (6”) gap between the stump of the trunk and the stem.
B. Make vertical cuts through the bark of the stump and peel the bark back slightly to expose about one inch (1”) of the inner wood.
C. Apply a thick paste made from ammonium sulfamate crystals, or spray apply weed killer to the exposed surfaces of the stump. BE CAREFUL NOT TO GET ANY ON THE MASONRY.
D. Allow the vines to die naturally, then remove the dried tendrils and roots, taking care not to remove bits of masonry and mortar.
NOTE: DO NOT PULL THE VINES OFF OF THE WALL SURFACE.
- Large, heavy, mature vines may be more easily removed by cutting the network of stems into smaller sections.
CAUTION: MAKE SURE THAT FALLING PLANT MATERIAL DOES NOT DAMAGE THE BUILDING, THE SURROUNDING LANDSCAPING, OR INJURE THE WORKER. - If the root system of mature vines is extensive, it may be necessary to remove individual roots from each mortar joint.
- Perform repairs to the masonry (including and resetting individual bricks or stones) as removal proceeds to maintain the integrity of the wall surface.
- Do not leave any dead wood within joints of the wall. As the wood decays, voids may be left with the wall that can lead to more serious problems.
E. Gently scrub the wall with a stiff, non-metallic bristle brush and clean, clear water (sprayed at low pressure) to remove any remaining dried plant material.
G. For root pods that are more difficult to remove, try using low pressure steam while brushing with a stiff, non-metallic bristle brush.