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 repairing a detached batten roll seam on a sheetmetal roof. GENERALLY, THIS WORK SHOULD BE ACCOMPLISHED BY A EXPERIENCED ROOFING CONTRACTOR.
- A batten seam metal roof damaged by wind usually results in unclipped cross welts. A batten roll which has pulled away from the decking is usually caused by bad workmanship.
- A sheetmetal roof with batten roll seams is stronger in some ways than a sheetmetal roof with standing seams.
- Batten roll seams have a deeper profile than standing seams. This deeper profile enhances the rigidity of the bays.
- More material is required in the upstands to the rolls, so the net width of bay for a given width of sheet or strip is less than with standing seams. This also provides added strength to the system.
- 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 and secure it to a substantial chimney or to a window on the opposite side of the house. Leave only enough slack so you can work comfortably in one area, and adjust the 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 roof slopes greater than 4 inches rise per foot, special consideration must be given to both footing and materials handling.
- Secure chicken ladders or cleats at the top for adequate footing.
- Hang and secure approved safety lines with ropes of sufficient strength.
- Carry a limited number of materials so that balance and footing are not impaired.
- Historic Structures Precautions:
- Historic and regional roofing craftsmanship examples characteristic of the structure are to be treated with sensitivity, to be preserved and followed.
- Historic work tolerances--Dimensions and general tolerances: Replacement, repair and new roofing work shall be equal to original workmanship. Roofing repair shall match prototype exposure, size, pattern and material. Reinstall using existing or compatible fastenings.
- See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelinescover 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).
- Anneal - the operation of heating and cooling the metal to soften it and make it less brittle.
- Brazing - to solder with a non-ferrous metal that melts at a lower temperature than that of the metals being joined.
- Bay - a unit of sheet covering as laid between rolls or standing seams.
- Capping - a metal strip, covering the top of a batten roll, welted to the edges of the sheets which are dressed up the side of the roll.
- Cleats or Clips - metal strips, cut to lengths to suit roll or seam, placed at intervals and securely fixed to the roof base, the ends being welted in with the edges of the sheets to hold the metal roofing in position.
- Lock Joint - a single or double welted joint.
- Roll-common, intersecting, or ridge - a shaped timber core against the sides of which the metal is dressed or turned up.
- Saddle End - the completion of a batten roll covering or a standing seam against an abutment.
- Solder - metal or metallic alloy of tin and lead used when melted to join metallic surfaces.
- Welting - joining metal sheets at their edges by folding together. Welted joints may consist of single or double folds, termed single or double welts respectively.
1.03 DELIVERY, STORAGE AND HANDLING
- Storage and Protection:
- Material storage: Keep uninstalled roof materials under cover, dry, free from scratches, condensation, and distortion during delivery, storage, and handling.
- Salvage storage: Historic material to be used as example of original construction shall be stored as directed by the Regional Historic Architect. Often original roof metal scrap pieces with exposed weather can be found in attic spaces.
1.04 PROJECT/SITE CONDITIONS
- Environmental Requirements: Do not repair metal roof in misty or rainy weather.
- The amount of maintenance required will depend on the kind of roofing used and the exposure hazards. It will also depend on the degree of waterproofing quality and exterior appearance that is acceptable.
- Rinse dirt with water annually.
- Keep the roof clear of debris, and trim all overhanging branches that might cause mechanical damage.
- Inspect for and remove any debris which can corrode sheetmetals.
- Inspect the secureness of cleats and fasteners and the condition of the sheetmetal after particularly heavy storms.
- see also Technical Procedure 0761004R for list.
- Revere Copper www.revere.com
- Zappone www.zappone.com
- Metal Sales Mfg. Corp. www.metalsales.us.com
- Vulcan Supply Corporation www.paradigmshingles.com
- Fine Metal Roof Tech www.finemetalrooftech.com
- Screws - #12 gauge steel, with counter sunk heads
- Hardwood block
- Hole saw
- Electric drill
- Cleats/patches to match metal of roof
- Sheetmetal to match existing
- Soldering flux
- Chicken ladder, safety belt or harness
- Protective gloves and gear
- Straight snips for cutting straight or slightly curved lines in sheetmetal 24 gauge or lighter
- Soldering copper, soldering iron
- Handy tongs for bending the edges of the solder
- At the end of each work day, provide building protection for any exterior roofing element removed for repair or replacement.
- Repair only a quantity of roofing which may be completed 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 trees trimmed to prevent branches from scuffing roofing surfaces.
- Use scaffolding, ladders, and working platforms as required to execute the work. Ladders shall not be supported on hanging gutters. They may be distorted which can affect the slope to drain.
- Establish regulations for roof 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.
3.02 ERECTION, INSTALLATION, APPLICATION
- If underside of roof is accessible, batten roll seam may be fixed from the underside of the roof deck.
- Relocate the screws or nails in the original holes.
- Drive the roll and fastenings until the underside of the roll is in close contact with the roof deck. BE SURE THE FASTENINGS DO NOT PENETRATE CAPPING.
- Use a hardwood block on top of the roll to protect the capping, paying particular attention to any fastenings that are forced back up through the roll, they are easily identified by small bumps in the capping.
- Locate the centerline of the batten roll on the underside of the deck.
- If the existing screws are long enough to have penetrated both the batten and the roof deck, the centerline should be apparent.
- If the existing screws do not penetrate the batten and the roof deck:
- ) Drill 2 small, no more that half the diameter of the #12 screws, on the top side of the roll at each end of the loose batten. Drill through to the underside of the deck.
- ) Strike a chalk line on the deck between these two points to mark the center line of the batten.
- ) Drill pilot holes along this line, spaced no more than 18" apart.
- ) If possible, have someone press down on the roll from above while inserting new #12 gauge steel screws, with counter sunk heads, through the deck, but NOT all the way through the batten. BE SURE PILOT HOLES AND/OR FASTENINGS DO NOT PENETRATE CAP.
- Patch the small holes left in the capping by soldering a small disc of the same sheetmetal, about the size of a penny, over the holes.
- If the underside of roof is NOT accessible:
- Remove the capping strip by carefully opening the single welts attaching it to the bay upstands.
- Drive existing fasteners below the top surface of the roll, providing new screws in different positions as required.
- Replace the capping strip -or- if the original capping cannot be salvaged or reused, prepare the replacement capping strip from new metal of the same thickness of the original.
- Dress the half-welt edges of the bays flat on the support of a metal bar.
- Do not attempt to anneal the edges because the timber batten will ignite .
- Repairing a Batten Roll Seam with Minimal Disturba= nce to Existing Surface:
- Use a 1/2"-5/8" diameter hole saw and electric drill to cut holes in the metal capping strip at the required centers.
- Continue to drill with a 1/4 inch twist bit to countersink the hole into the top of the roll.
- Refasten the roll with #12 gauge steel screws of sufficient length to penetrate the batten roll and roof deck.
- Solder metal discs 1" to 1-1/4" in diameter over the holes in the capping strip (see 05010-07-R for guidance on soldering metal).
- If needed, the new metal can be made to blend in with a well-weathered roof by artificial patination.