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.
- This procedure includes guidance on making minor repairs to a metal shingle roof.
- Safety Precautions:
- Wear rubber-soled shoes that have non-slip tread (preferably sneakers with a high top for good ankle support). Avoid wearing loose clothing.
- Wear a safety-belt or harness and secure it to the chimney or other substantial object. Leave only enough slack so that work can be performed comfortably in one area, and adjust that slack as you work 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 slopes where the roof is steeper than 4 inches rise per foot, special consideration must be given to footing and handling of materials.
- Secure chicken ladders or cleats at the top for adequate footing.
- Hand and secure approved safety lines with ropes of sufficient strength.
- Carry a limited number of materials so that balance and footing are not impaired.
- Establish regulations for any foot traffic. Many roofing materials should not be walked on. When working on lead roofing, a self-supporting ladder might be hung from the roof ridge. Such items should be specifically designed and kept in a storage area adjacent to the roof access. Plank ceiling joists under roof hatch.
- 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).
1.02 PROJECT/SITE CONDITIONS
- Environmental Requirements:
- Wet weather: Do not repair roofing in misty, rainy weather. Do not apply paint, putty or epoxy to damp surfaces or in misty or rainy weather. Do not remove exterior elements of structures when rain is in the forecast or in progress.
- Hot weather: Maximum application temperatures: Paint--85 degrees F, Putty--80 degrees F, and Epoxy--80 degrees F. Work in shade when temperature is above 75 degrees F. Work around the structure in the shade away from the sun.
- Cold weather: Minimum application temperatures: Paint -- 50 degrees F, Putty--50 degrees F, and Epoxy--55 degrees F.
- Rinse dirt with water annually.
- Keep the roof clear of debris, and trim all overhanging branches that might cause mechanical damage.
- Inspect for and eliminate ant hills and/or bird droppings which can corrode sheet metals.
- Inspect the secureness of cleats and fasteners and the condition of the sheet metal after particularly heavy storms.
- Berridge Manufacturing Company www.berridge.com
- Gerard Roofing Technologies www.gerardusa.com
- W.F. Norman Corp. www.wfnorman.com
- Zappone Manufacturing www.zappone.com
- Other sources: see Traditional Building Magazine,www.traditional-building.com; and other building trades publications and websites.
- Metal shingles to match existing
- Sheet metal (for patch) compatible with metal shingles
- Rivets or nails compatible with sheetmetal type
- Solder, flux
- Silicone sealer
- Flashing cement
- Chicken ladder, safety belt or harness
- Protective gloves and gear
- Straight snips for cutting straight or slightly curved lines in sheet metal 24 gauge or lighter
- Soldering copper, soldering iron
- Handy tongs for bending the edges of the solder
- Wire brush or steel wool
- At the end of each work day, provide building protection for any exterior roofing element removed for repair or replacement.
- Remove only a quantity of roofing which may be replaced on that same day. At the end of the day, use 15 pound roofing felt or polyethylene sheeting to drape over missing roofing and insert under roof unit laps or temporarily secure areas of existing roofing and roof as required to make roof watertight and windproof.
- Keep areas trimmed to prevent branches from scuffing roofing surfaces.
3.02 ERECTION, INSTALLATION, APPLICATION
- For Small Rusted Areas:
- Remove rust using a wire brush.
- Apply an iron oxide primer.
- Apply a finish coat of paint to match existing.
NOTE: METAL SHINGLES OF GALVANIZED OR TERNE-COATED STEEL WILL LAST MANY YEARS IF KEPT PAINTED.
- For Damaged Metal Shingles: Solder a patch.
NOTE: A SINGLE METAL SHINGLE IS ALMOST IMPOSSIBLE TO REPLACE BECAUSE OF THE WAY THEY INTERLOCK. THEREFORE, PATCHING IS THE BEST REPAIR SOLUTION. FOR INDIVIDUAL SHINGLE REPLACEMENT, SEE SECTION 3.02 D. BELOW.
- Thoroughly clean the area to be patched of all rust and/or roofing cement - clean down to shiny metal.
- Cut a patch from the same metal, about two inches larger than the hole.
- Fold the edges under 1 (one) inch and snip off the corners. This makes the patch stronger and takes off easily damaged sharp corners.
- Place a weight, such as a brick, over the patch to hold it firmly to the metal. If the patch is on a vertical surface, clamp or tack-solder it in place.
- Solder patch in place (see 05010-07-R for guidance on soldering metal).
- If a soldered repair is not feasible, try patching the shingle using a commercial sealing product such as gutter tape or a tripolymer adhesive with tape backing. -OR- Patch the damaged shingle with sheetmetal and flashing cement:
- Clean the metal with a wire brush or steel wool.
- Cut a sheet-metal patch that overlaps the hole at least 3 inches on all sides.
- Coat the back of the patch with flashing cement.
- Press the patch firmly into place--just hard enough so that the cement doesn't ooze onto the roof.
- Prime and paint the patch to match the rest of the roof.
NOTE: THESE PATCHES ARE ONLY TEMPORARY.
- For Individual Shingle Replacement:
- If it is possible to remove one (or a few) shingle(s) for replacement, fit replacement or repaired shingle into place.
- Secure shingle by toenailing two nails (each nail 1" from shingle edge) through shingle at exposure line. If possible, nail so that nail heads will be covered by butt of the shingle in the above course.
- Cover nail head with a dab of clear silicone sealer.