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Historic Preservation - Technical Procedures

Spectitle:

Repairing A Detached Batten Roll Seam On A Sheetmetal Roof

Procedure code:

0761010R

Source:

Hspg Prepared For Nps - Sero

Division:

Thermal And Moisture Protection

Section:

Sheet Metal Roofing

Last Modified:

02/24/2012

Details:

Repairing A Detached Batten Roll Seam On A Sheetmetal Roof



REPAIRING A DETACHED BATTEN ROLL SEAM ON A SHEETMETAL ROOF


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on repairing a detached
         batten roll seam on a sheetmetal roof.  GENERALLY, THIS
         WORK SHOULD BE ACCOMPLISHED BY A EXPERIE= NCED ROOFING
         CONTRACTOR.

    B.   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.

    C.   A sheetmetal roof with batten roll seams is strong= er in
         some ways than a sheetmetal roof with standing seams.  

         1.   Batten roll seams have a deeper profile than
              standing seams.  This deeper profile enhances the
              rigidity of the bays.  

         2.   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.

    D.   Safety Precautions:

         1.   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.
             
         2.   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.

         3.   Be sure the roof is clear of debris and water.

         4.   Do not work on wet snow covered roofs.  Work on
              cleated walkboards.

         5.   Steep roofs:  On roof slopes greater than 4 inches
              rise per foot, special consideration must be given
              to both footing and mater= ials handling.

              a.   Secure chicken ladders or cleats at the top
                   for adequate footing.

              b.   Hang and secure approved safety lines with
                   manila rope

              c.   Carry a limited number of materials so that
                   balan= ce and footing are not impaired.

    E.   Historic Structures Precautions:

         1.   Historic and regional roofing craftsmanship
              examples characteristic of the structure are to be
              treated with sensitivity, to be preserved and
              followed.

         2.   Historic work tolerances--Dime= nsions and general
              tolerances: Replacement, repair and new roofing
              work shall be equal to original workmanship.
              Roofing repair shall match prototype exposure,
              size, pattern and materia= l.  Reinstall using
              existing or compatible fastenings.  

    F.   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 Precaution= s

         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 DEFINITIONS

    A.   Anneal - the operation of heating and cooling the metal
         to soften it and make it less brittle.
    B.   Brazing - to solder with a non-ferrous metal that melts
         at a lower temperature than that of the metals being
         joined.

    C.   Bay - a unit of sheet covering as laid between rolls or
         standing seams.  

    D.   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.

    E.   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.

    F.   Lock Joint - a single or double welted joint.

    G.   Roll-common, intersecting, or ridge - a shaped timber
         core against the sides of which the metal is dressed or
         turned up.

    H.   Saddle End - the completion of a batten roll cover= ing or
         a standing seam against an abutment.

    I.   Solder - metal or metallic alloy of tin and lead used
         when melted to join metallic surfaces.
    J.   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

    A.   Storage and Protection:

         1.   Material storage:  Keep uninstalled roof materials
              under cover, dry, free from scratches,
              condensation, and distort= ion during delivery,
              storage, and handling.

         2.   Salvage storage:  Historic material to be used as
              example of original const= ruction 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

    A.   Environmental Requirements:  Do not repair metal roof in
         misty or rainy weather.

1.05 MAINTENANCE

    A.   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 waterproofi= ng quality and
         exterior appearance that is acceptable.<= br>
    B.   Rinse dirt with water annually.

    C.   Keep the roof clear of debris, and trim all overha= nging
         branches that might cause mechanical damage.

    D.   Inspect for and eliminate ant hills and/or bird droppings
         which can corrode sheetmetals.

    E.   Inspect the secureness of cleats and fasteners and the
         condition of the sheetmetal after partic= ularly heavy
         storms.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Follansbee Steel
         State St.
         Follansbee, WV  26037
         800/624-6906

         Standing-seam and batten-seam roofing sold through
         distributors.  Free brochure.

    B.   Metal Sales Mfg. Corp.
         Deer Lake Industrial Park
         P.O. Box 158
         Orwigsburg, PA  17961
         717/366-2020

         Large, diversified manufacturer of flat metal roofing
         panels, also barrel type tiles.  Fr= ee literature.

2.02 MATERIALS

    A.   Screws - #12 gauge steel, with counter sunk heads<= br>
    B.   Hardwood block

    C.   Hole saw

    D.   Electric drill

    E.   Cleats/patches to match metal of roof

    F.   Sheetmetal to match existing

    G.   Solder
   
    H.   Soldering flux

2.03 EQUIPMENT

    A.   Chicken ladder, safety belt or harness

    B.   Protective gloves and gear

    C.   Straight snips for cutting straight or slightly curved
         lines in sheetmetal 24 gauge or lighter<= br>
    D.   Soldering copper, soldering iron

    E.   Handy tongs for bending the edges of the solder


PART 3---EXECUTION

3.01 PREPARATION

    A.   Protection:

         1.   At the end of each work day, provide building
              protection for any exteri= or roofing element removed
              for repair or replacement= .

         2.   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 requi= red to make roof
              watertight and windproof.=

         3.   Keep trees trimmed to prevent branches from
              scuffing roofing surfaces= .

         4.   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.

         5.   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

    A.   If underside of roof is accessible, batten roll seam may
         be fixed from the underside of the roof deck.

         1.   Relocate the screws or nails in the original holes.

         2.   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.

         3.   Use a hardwood block on top of the roll to protect
              the capping, paying parti= cular attention to any
              fastenings that are forced back up through the
              roll, they are easily identified by small bumps in
              the capping.

         4.   Locate the centerline of the batten roll on the
              underside of the deck.  

              a.   If the existing screws are long enough to have
                   penet= rated both the batten and the roof deck,
                   the centerline should be apparent.

              b.   If the existing screws do not penetrate the
                   batten and the roof deck:

                   1)   Drill 2 small, =AC diameter holes on the
                        top side of the roll at each end of the
                        loose batten.  Drill through to the
                        underside of the deck.  

                   2)   Strike a chalk line on the deck between
                        these two points to mark the center line
                        of the batten.

                   3)   Drill pilot holes along this line, spaced
                        no more than 18" apart.  

                   4)   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.

         5.   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.

    B.   If the underside of roof is NOT accessible:
   
         1.   Remove the capping strip by carefully opening the
              single welts attaching it to the bay upstands.

         2.   Drive existing fasteners below the top surface of
              the roll, providing new screws in different
              positions as required.

         3.   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.

         4.   Dress the half-welt edges of the bays flat on the
              support of a metal bar.
         5.   Do not attempt to anneal the edges because the
              timber batten will ignite= .

    -OR-

    C.   Repairing a Batten Roll Seam with Minimal Disturba= nce to
         Existing Surface:

         1.   Use a 1/2"-5/8" diameter hole saw and electric
              drill to cut holes in the metal capping strip at
              the required centers.

         2.   Continue to drill with a 1/4&q= uot; twist bit to
              countersink the hole into the top of the roll.

         3.   Refasten the roll with #12 gauge steel screws of
              sufficient length to penetrate the batten roll and
              roof deck.
 
         4.   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).

         5.   If needed, the new metal can be made to blend in
              with a well-weathered roof by artificial
              patination.

                             END OF SECTION