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Historic Preservation - Technical Procedures

Spectitle:

Guidelines For Installing A Standing Seam Sheetmetal Roof

Procedure code:

0761001R

Source:

Us Custom House, Portland, Or - Gsa/Facil Support Center

Division:

Thermal And Moisture Protection

Section:

Sheet Metal Roofing

Last Modified:

02/24/2012

Details:

Guidelines For Installing A Standing Seam Sheetmetal Roof



GUIDELINES FOR INSTALLING A STANDING SEAM SHEET METAL ROOF


PART 1---GENERAL

1.01 SUMMARY

    A.   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.

    B.   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.

    C.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   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 REFERENCES

    A.   American Society for Testing and Materials (ASTM), 100
         Barr Drive, West Conshohocken, PA 19428, (610) 832-9585
         or FAX (610) 832-9555.

    B.   American National Standards Institute, Inc. (ANSI), 1430
         Broadway, New York, NY  10018.

1.03 SUBMITTALS

    A.   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.

         1.   List compliance with all specified qualities.

    B.   Shop Drawings:  Provide showing all details of assembly
         proposed for use.

         1.   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.

         2.   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.

    C.   Materials Lists and Certificates:

         1.   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

    A.   Packing and Shipping:  Box, crate, palletize and wrap
         materials with weatherproof covering during shipment,
         handling and storage.

    B.   Storage and Protection:  

         1.   Protect materials from exposure to elements and
              keep dry at all times.

         2.   Protect against impact, abrasion, discoloration,
              and other damage.

         3.   Replace damaged article, or refinish any damage to
              original condition, before installation and
              acceptance.

1.05 WARRANTY

    A.   Provide copies of all manufacturer's guarantees of
         proprietary roofing systems, materials, and installation,
         duly signed and dated.

    B.   Include all warranty inspections by a manufacturer's
         representative necessary to effect the guarantee of
         material performance and its installation.


PART 2---PRODUCTS

2.01 MATERIALS

    A.   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.

         1.   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.

    B.   Solder:  ASTM B32-83; 50/50.

    C.   Soldering Flux: Type best suited for specific metal.

    D.   Nails & Fasteners:  Use type and form of metal fastener
         compatible with the base metal and support structure;
         non-corroding type or hot dip galvanized.

    E.   Roofing Felt:  Asphalt saturated felt, 15-lb. or 30-lb.
         weight, unperforated; ASTM Designation, D224-81.

    F.   Building Paper:  Rosin sized, unsaturated paper, 6-lb.
         per 100-sq. ft.

    G.   Sealant:  See 07900-02-S for guidance.

    H.   Bituminous Coating:  Black asphaltic enamel for metal
         priming and coating, a galvanic barrier.  

2.02 ACCESSORIES

    A.   Soldering Coppers:  Heavy weight, 10-lb., and stove to
         heat them or electric or gas heated, necessary to fully
         solder seams.

    B.   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.


PART 3---EXECUTION

3.01 PREPARATION

    A.   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.

    B.   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

    A.   Cleating:  For size and spacing, see SMACNA manual.

         1.   Secure one end with two fasteners and fold the
              cleat over the fastener heads.

         2.   Unless otherwise specified, use 2" wide by 3" long
              cleats of the same material and thickness of metal
              being installed.

    B.   Soldering:  Included only where bare sheet metal work is
         employed.  See 05010-07-S for soldering procedures.

         1.   Perform with well-heated coppers, so as to heat
              thoroughly the seam and sweat the solder through
              its full width.

         2.   Roughen edges of stainless steel and Monel with
              emery cloth before soldering.

    C.   Flux:  Use type of flux compatible with the sheet metal.

         1.   Remove acid flux residue by neutralizing with
              ammonia or baking soda solution and rinsing with
              water.

    D.   Seams:  Comply with SMACNA manual Plates No. 99, 120, and
         121 and other plates applicable to specific
         installations; otherwise:

         1.   Standing seams - Finish not less than 1" high
              unless otherwise specified.

         2.   Flat-lock seams - Finish not less than 3/4" wide.

         3.   Lap seams where soldered or sealant filled - Finish
              not less than 1" wide.

         4.   Lap seams, not soldered - Overlap 4" unless
              otherwise noted.

         5.   Orient seams properly for direction of water flow
              to prevent leaking.

    E.   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.

    F.   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".

    G.   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

    A.   Allow for expansion and contraction of sheet metal as
         recommended by SMACNA.

         1.   Allow 1/8 in. clearance between abutting sheets
              when installing them in temperatures below 50 deg.
              F. (10 deg. C).

    B.   Maintain the integrity of underlayment asphalt and
         building paper; repair torn sheets with well lapped new
         paper as required.

    C.   Install sheet metal so it lies flat and is not buckled or
         stressed.

    D.   No exposed cut standing or projecting edges of sheet
         metal, all edges to be hemmed, soldered, or flush with
         other metal.

    E.   No exposed fastenings projecting through any roofing
         surface unless so detailed; cover any surface fastenings
         with soldered dutchmen or metal caps.

         1.   No cap soldering over fastenings without a metal
              cap or dutchman.

3.04 ADJUSTING/CLEANING

    A.   Wash completed sheet metal work to remove all oils,
         residue of fluxes, and dirt.  Clean off any excess
         sealers.

                         END OF SECTION