Patching Metal Gutters
- CSI Division:
- Division 7 - Thermal and Moisture Protection
- Gutters & Downspouts
- Last Modified:
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.
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.
A. This procedure includes guidance on patching metal gutters using a soldered metal patch, a caulked metal patch or a fabric patch.
B. Gutters with soldered joints are usually under continual stress due to expansion and contraction following changes in temperature. An overloaded gutter can also cause holes, popped seams, and deteriorated straps.
C. Safety Precautions:
- Wear rubber-soled shoes that have non-slip or grid type tread (preferably sneakers with a high top for good ankle support). Avoid wearing loose clothing.
- Wear a safety belt or harness secured to a chimney or other substantial element. Leave only enough slack to perform the work comfortably in one area, and adjust the slack as the work proceeds on other sections of the roof.
- Be sure the roof is clear of debris and water.
- Do not work on wet or snow-covered roofs. Work on cleated walkboards.
- Steep roofs: On roof slopes greater than 4 inches rise per foot, special consideration must be given to both footing and materials handling.
- Chicken ladders or cleats secured at the top for adequate footing.
- Approved safety lines should be secured with manila rope.
- Carry a limited amount of materials so that balance and footing are not impaired.
- Scaffolding, ladders and working platforms as required to execute this work.
D. 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
- 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).
A. Sheetmetal and Gutters: (for metal patch)
- Albert J. Wagner & Son
3762 N. Clark Street
Chicago, IL 60613
- Conklin Metal Industries
P.O. Box 1858
Atlanta, GA 30301
- Davenport, Peters
129 South Street
Boston, MA 02111
- J.C. Lauber Co.
504 E. LaSalle Ave.
South Bend, IN 46617
- Revere Products (division of Pioneers)
P.O. Box 35311
Cleveland, OH 44131-0311
216/573-7100 "Miracle Seal"
- Magic American Chemical Corp.
23700 Mercantile Rd.
Cleveland, OH 44122
216/464-2353 "Patch Magic"
- Evode, Inc.
Somerdale, NJ "
- Geocel, Ltd.
53280 Marina Dr.
Elkhart, IN 46514
C. Silicone Caulk:
- Dow Corning Corporation
1225 Northmeadow Parkway,
Roswell, GA 30076
800/662-0661 ext. 40
NOTE: Chemical products are sometimes sold under a common name. This usually means that the substance is not as pure as the same chemical sold under its chemical name. The grade of purity of common name substances, however, is usually adequate for stain removal work, and these products should be purchased when available, as they tend to be less expensive. Common names are indicated below by an asterisk (*).
B. Rosin soldering flux
C. Gutter sealant such as "Miracle Seal" (Revere Chemical Corp.), "Patch Magic" (Magic American Chemical Corp.), "Flashband" (Evode, Inc.), "Geocel Water Seal 100" (Geocel, Ltd.), or approved equal.
D. Silicone caulk
E. Metal primer such as Rust-Oleum, or approved equal
F. Flashing cement or roofing compound for embedding fabric patch
G. Burlap, roofing membrane or building paper
H. Appropriate metal for patching material
I. Mineral spirits:
- A petroleum distillate that is used especially as a paint or varnish thinner.
- Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.
- Potential Hazards: TOXIC AND FLAMMABLE.
- Safety Precautions:
- AVOID REPEATED OR PROLONGED SKIN CONTACT.
- ALWAYS wear rubber gloves when handling mineral spirits.
- If any chemical is splashed onto the skin, wash immediately with soap and water.
- Available from construction specialties distributor, hardware store, paint store, or printer's supply distributor.
J. Muriatic acid:
- A strong corrosive irritating acid. Generally available in 18 degree and 20 degree Baume solutions.
- Other chemical or common names include Chlorhydric acid; Hydrochloric Acid (30-35%); Hydrogen chloride; Marine acid*; Spirit of salt*; Spirit of sea salt*.
- Potential Hazards: TOXIC, CORROSIVE TO FLESH; CORROSIVE TO CONCRETE, STEEL, WOOD OR GLASS, FLAMMABLE.
- Available from chemical supply house, drugstore or pharmaceutical supply distributor, or hardware store.
A. Safety belt or harness
B. Ladders and scaffolding
C. Chicken ladder, safety belt or harness
D. Soldering copper, soldering iron
E. Straight snips for cutting straight or slightly curved lines in sheet metal 24 gauge or lighter
F. Handy tongs for bending the edges of the solder
G. Wire brush or steel wool
H. Clean, soft cloths
I. Heavy gloves and protective gear
A. Inspect for:
- Metal corrosion factors: In varying degrees each type of sheet metal is likely to deteriorate from chemical action resulting in pitting or streaking. The cause may be airborne pollutants, acid rainwater, acids from lichen or moss, or alkalis found in mortar.
- Maintenance problems: Corrosion around nails. Roof cement on gutters may hide leaks that have not been corrected.
- Inspect for gutters that are split or cracked with loose, broken, out of place, hangers, corners or slopes, or pulling of fasteners, broken joints or seams; excessive staining or punctures of gutter fabric.
- Inspect for signs of deteriorated mortar joints and/or paint that is peeling, cracking, alligatoring, chipping, or chalking on surfaces behind gutters and downspouts.
- Inspect for cracks, splits, punctures, and dirt stains on downspouts as well.
B. Inspect the underside of the roof cornices. Water stains may be evidence of ice dams.
C. Check gutters as a part of the annual roof inspection (preferably in late autumn). Repair defects immediately because gutters are a critical part of the roof fabric. Small gutter leaks may force water into concealed cornice and roof areas leading to major defects. It is recommended that a professional survey be carried out every five years.
D. Inspect soldered gutters annually, and re-solder any broken joints.
NOTE: SOLDERING USUALLY REQUIRES A FAIRLY HIGH LEVEL OF EXPERIENCE.
E. Inspect all parts of the drainage system, including downspouts, flashing, conductor heads, leaders, roof drains, and scuppers. Be sure to include these in the work list when maintenance or repair are being made to the gutters.
F. See also 07631-01-S "General Inspection and Maintenance of Gutters and Downspouts".
- At the end of each work day, provide building protection for any exterior gutter element removed for repair or replacement, if water penetration is possible.
- Landscape work adjacent to or within the ground work areas for gutter maintenance shall be protected. Provide plank barriers to protect tree trunks. Tie-up spreading shrubs, and cover as necessary, allowing the plants to breathe. Remove the covering and ties at the end of each work day. Set scaffold ladder and legs away from plants. Pruning requests shall be directed to the Regional Architect.
- Keep trees trimmed to prevent branches from scuffing or moving downspouts.
- Set ladders on an incline whereby the bottom of the ladder is approximately 25% of the height from the base of the building. Do not rest ladders on gutters.
B. Surface Preparation:
- Flush silty residue to the downspout. Remove strainers.
- When moss, lichen, or fungus is present, wipe or scrape off growth. Saturate biological areas with a disinfectant solution.
3.03 ERECTION, INSTALLATION, APPLICATION
A. Repairing With a Soldered Metal Patch:
NOTE: USE A METAL PATCH MADE FROM THE SAME METAL AS THE GUTTER. IF DISSIMILAR METALS ARE USED, GALVANIC CORROSION IS LIKELY TO OCCUR.
- Remove all deteriorated and corroded metal using a wire brush or steel wool.
- Cut patching material so that it overlaps sound metal by 2 inches on all sides of the damaged area.
- To allow for the normal expansion and contraction of the material, solder patch on the "uphill" side of the patch only.
- With chemical paint stripper, remove any paint from the metal surrounding the patch. If there's any roofing tar, remove it by scraping, followed by scrubbing with mineral spirits.
CAUTION: THIS SOLVENT IS VERY FLAMMABLE.
- Clean the gutter and the metal patch piece by scouring with a wire brush or steel wool.
- For guidance on soldering, see 05010-07-R "Procedures for Soldering Metal". -OR-
B. Repairing With a Caulked Metal Patch:
- Clean the gutter thoroughly by scouring with a wire brush or steel wool.
- Cut a metal patch of appropriate size made from the same metal as the gutter.
- Apply a liberal amount of silicone caulk over the area to be patched.
- Bed the metal patch firmly in the caulk, paying special attention to the seal at both ends of the patch.
NOTE: ALTHOUGH SILICONE CAULK SHOULD HAVE A USEFUL LIFE OF 10 OR MORE YEARS, THIS KIND OF PATCH REQUIRES CAREFUL MONITORING THROUGH ANNUAL MAINTENANCE CHECKUPS. -OR-
C. Repairing With a Fabric Patch:
- Clean the gutter thoroughly by scouring with a wire brush or steel wool.
- Apply metal primer such as Rust-Oleum, or approved equal, to protect the metal from acids contained in black roofing compound or flashing cement (used in securing the fabric patch).
- Apply a coating of flashing cement or roofing compound.
- Imbed a fabric material such as burlap, roofing membrane or building paper in the cement.
- Cover patch with another coat of flashing cement.
CAUTION: AVOID COATING THE ENTIRE METAL GUTTER WITH A COATING SUCH AS ROOFING CEMENT. IF ANY WATER DOES GET UNDER SUCH A COATING, IT WILL BE HELD IN CONTACT WITH THE METAL INDEFINITELY.
D. Commercial products such as "Miracle Seal" or "Patch Magic," may also be used. Follow manufacturer's instructions.