Guidelines For Installing A Standing Seam Sheetmetal Roof
- CSI Division:
- Division 3 - Concrete
- Sheet Metal Roofing
- Last Modified:
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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 general guidelines for installing standing seam sheet metal roofing and related flashing. GENERALLY, THIS WORK SHOULD BE PERFORMED BY AND EXPERIENCED CONTRACTOR.
- This procedure may also be adapted to replacement of damaged areas of otherwise sound standing seam metal roofing. Replacement roofing should match original in color, detailing and dimensioning.
- 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).
- American Society for Testing and Materials (ASTM) www.astm.org
- American National Standards Institute, Inc. (ANSI) www.ansi.org
- Product Data: Submit complete product brochures and catalog pages showing details of installation and assembly as well as materials, colors available, for all proprietary metal roofing systems proposed for use.
- List compliance with all specified qualities.
- Shop Drawings: Provide showing all details of assembly proposed for use.
- Copies of SMACNA manual illustrations may be used in lieu of shop drawings where those details will be the ones proposed for use as specified.
- Show roof plan and layout of all pan sections, standing seams, flat seams, flashings, ridges, and other details of the roofing system and their location on the roof.
- Materials Lists and Certificates:
- Provide a complete list of all materials and products proposed for use in the roofing system and required to complete the assembly.
1.04 DELIVERY, STORAGE AND HANDLING
- Packing and Shipping: Box, crate, palletize and wrap materials with weatherproof covering during shipment, handling and storage.
- Storage and Protection:
- Protect materials from exposure to elements and keep dry at all times.
- Protect against impact, abrasion, discoloration, and other damage.
- Replace damaged article, or refinish any damage to original condition, before installation and acceptance.
- Provide copies of all manufacturer's guarantees of proprietary roofing systems, materials, and installation, duly signed and dated.
- Include all warranty inspections by a manufacturer's representative necessary to effect the guarantee of material performance and its installation.
- Sheet Metal: Zinc-Aluminum alloy coated sheet steel for roofing and flashing, ASTM Designation A 875/A 875M: Specification for Steel Sheet, Zinc-5% Aluminum Alloy Metallic-Coated by the Hot Dip Process.
- Performance and Design Requirements: Factory prefinished zinc-aluminum alloy coated sheet steel roofing, standing seam style per SMACNA Plates No. 120 and 121, folded seam without separate cover strip.
- Solder: ASTM B32-83; 50/50.
- Soldering Flux: Type best suited for specific metal.
- Nails & Fasteners: Use type and form of metal fastener compatible with the base metal and support structure; non-corroding type or hot dip galvanized.
- Roofing Felt: Asphalt saturated felt, 15-lb. or 30-lb. weight, unperforated; ASTM Designation, D224-81.
- Building Paper: Rosin sized, unsaturated paper, 6-lb. per 100-sq. ft.
- Sealant: See 07900-02-S for guidance.
- Bituminous Coating: Black asphaltic enamel for metal priming and coating, a galvanic barrier.
- Soldering Coppers: Heavy weight, 10-lb., and stove to heat them or electric or gas heated, necessary to fully solder seams.
- Finishes: Factory applied synthetic, standard with the manufactured system, color as selected by Architect from standard colors, guaranteed for 12 years for durability and resistance to fading, flaking and rust damage.
- Remove existing roofing complete, including all flashing. Clean out all flashing reglets in perimeter masonry so as to facilitate the restoration of original interlocking flashing assemblies.
- Do not proceed with the work until curb and substrate construction, cant strips, blocking, reglets, and other construction to receive the work is completed.
3.02 ERECTION, INSTALLATION, APPLICATION
- Cleating: For size and spacing, see SMACNA manual.
- Secure one end with two fasteners and fold the cleat over the fastener heads.
- Unless otherwise specified, use 2" wide by 3" long cleats of the same material and thickness of metal being installed.
- Soldering: Included only where bare sheet metal work is employed. See 05010-07-S for soldering procedures.
- Perform with well-heated coppers, so as to heat thoroughly the seam and sweat the solder through its full width.
- Roughen edges of stainless steel and Monel with emery cloth before soldering.
- Flux: Use type of flux compatible with the sheet metal.
- Remove acid flux residue by neutralizing with ammonia or baking soda solution and rinsing with water.
- Seams: Comply with SMACNA manual Plates No. 99, 120, and 121 and other plates applicable to specific installations; otherwise:
- Standing seams - Finish not less than 1" high unless otherwise specified.
- Flat-lock seams - Finish not less than 3/4" wide.
- Lap seams where soldered or sealant filled - Finish not less than 1" wide.
- Lap seams, not soldered - Overlap 4" unless otherwise noted.
- Orient seams properly for direction of water flow to prevent leaking.
- Dissimilar Metals: Place building paper between dissimilar metals or paint with asphaltum paint. CAUTION: Some bituminous roofing cements will attack copper and terne metal. Red Rosin paper is the preferred choice for use with these materials.
NOTE: THE USE OF ROOFING FELTS UNDER COPPER OR TERNE METAL IS GENERALLY NOT RECOMMENDED BECAUSE THE BITUMEN IN THE FELTS HAVE A NEGATIVE REACTION WITH THESE MATERIALS. RED ROSIN PAPER SHOULD BE USED INSTEAD.
- Underlayment: Apply 30 lb. roofing felt followed by a layer of building paper to surfaces receiving metal roofing, valleys and gutter linings; lap plies 2".
- Flashings: Make all new flashings for perimeter and roof penetration joints to match the original work and in accordance with SMACNA approved details.
3.03 FIELD QUALITY CONTROL
- Allow for expansion and contraction of sheet metal as recommended by SMACNA.
- Allow 1/8 in. clearance between abutting sheets when installing them in temperatures below 50 deg. F. (10 deg. C).
- Maintain the integrity of underlayment asphalt and building paper; repair torn sheets with well lapped new paper as required.
- Install sheet metal so it lies flat and is not buckled or stressed.
- No exposed cut standing or projecting edges of sheet metal, all edges to be hemmed, soldered, or flush with other metal.
- No exposed fastenings projecting through any roofing surface unless so detailed; cover any surface fastenings with soldered dutchmen or metal caps.
- No cap soldering over fastenings without a metal cap or dutchman.
- Wash completed sheet metal work to remove all oils, residue of fluxes, and dirt. Clean off any excess sealers.