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Historic Preservation - Technical Procedures

Spectitle:

Supplemental Guidelnes For Repairing & Replacing Slate Roofs

Procedure code:

0731504S

Source:

Federal Building/Us Courthouse, Eau Claire, Wi

Division:

Thermal And Moisture Protection

Section:

Slate Shingles

Last Modified:

02/24/2012

Details:

Supplemental Guidelnes For Repairing & Replacing Slate Roofs



SUPPLEMENTAL GUIDELINES FOR REPAIRING AND REPLACING SLATE ROOFS


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure provides supplemental guidelines to be
         used when specifying repair or replacement work on slate
         roofs.  Guidelines for qualification, materials,
         fabrication and general guidelines for installation are
         included.  This procedure should be used to supplement
         07315-01-R and 07315-03-R.

1.02 SUBMITTALS

    A.   Product Data: Submit manufacturer's technical product
         data, installation instructions and recommendations for
         each type of roofing product required. Include data
         substantiating that materials comply with requirements.
         Submit three samples of slates. Submit samples of nails,
         rag felt and plastic cement.

1.03 QUALITY ASSURANCE

    A.   Manufacturer Qualifications: Provide primary products,
         produced by a single manufacturer, which has produced
         that type product successfully for not less than 3 years.
         Provide secondary products only as recommended by
         manufacturer of primary products for use with roofing
         system specified.

    B.   Installer Qualifications: A single Installer ("Roofer")
         shall perform the work of this section; and shall be a
         firm with not less than 5 years of successful experience
         in installation of slate shingle roofs similar to those
         required for this project and which is acceptable to or
         licensed by the manufacturer of primary roofing material.

         1.   Installer Certification: Obtain written
              certification from manufacturer certifying that
              installer is approved by manufacturer for
              installation of specified roofing system. Provide
              copy of certification to Contracting Officer prior
              to award of roofing work.

         2.   Installer's Field Supervision: Installer must
              maintain full-time supervisor/foreperson on jobsite
              during times that roofing work is in progress.
              Supervisor must have minimum of 5 years experience
              in roofing work similar to nature and scope of
              specified roofing.

         3.   Provide detailed written resume of slate
              installer's qualifications including at least 5
              examples of quality slate installations.

    C.   Pre-Application Roofing Conference: Approximately two
         weeks prior to scheduled commencement of slate shingle
         installation and associated work, meet at project site
         with Installer, installer of each component of associated
         work, other work in and around roofing which must precede
         or follow roofing work, the Contracting Officer,
         Government, roofing system manufacturer's representative,
         and other representatives directly concerned with
         performance of the work including (where applicable)
         Government's insurers, test agencies, and governing
         authorities. Record (Contractor) discussions of
         conference and decisions and agreements (or
         disagreements) reached, and furnish copy of record to
         each party attending. Review foreseeable methods and
         procedures related to roofing work, including but not
         necessarily limited to the following:

         1.   Tour representative areas of roofing substrates
              (decks), inspect and discuss condition of
              substrate, roof drains, curbs, penetrations and
              other preparatory work performed by other trades.

         2.   Review roofing system requirements (drawings,
              specifications and other contract documents).

         3.   Review required submittals, both completed and yet
              to be completed.

         4.   Review and finalize construction schedule related
              to roofing work and verify availability of
              materials, Installer's personnel, equipment and
              facilities needed to make progress and avoid
              delays.

         5.   Review required inspection, testing, certifying and
              materials usage accounting procedures.

         6.   Review weather and forecasted weather conditions,
              and procedures for coping with unfavorable
              conditions, including possibility of temporary
              roofing (if not a mandatory requirement).

1.04 DELIVERY, STORAGE AND HANDLING

    A.   Store in a dry, well ventilated, weather-tight place.
         Unless protected from weather or other moisture sources,
         do not leave unused felts on the roof overnight or when
         roofing work is not in progress.  Store rolls of felt and
         other sheet materials on end on pallets or other raised
         surface. Handle and store materials or equipment in a
         manner to avoid significant or permanent deflection of
         deck.

    B.   Felt rolls and shingles which are stored on roof
         overnight shall be covered with tarpaulins, not plastic.
         Coverage shall be complete, with tarpaulins extending to
         bottom to prevent exposure in wind. Material shall be
         stored in such a manner so as not to exceed 20 PSF
         loading on roof.

1.05 PROJECT/SITE CONDITIONS

    A.   Weather Condition Limitations: Proceed with roofing work
         only when existing and forecasted weather conditions will
         permit work to be performed in accordance with
         manufacturer's recommendations and warranty requirements.

    B.   Temporary Protection: Contractor shall be responsible for
         protection of spaces and contents below roof deck from
         water leakage. Roof deck shall never be left exposed
         overnight or during inclement weather.

    C.   The contractor shall be responsible for protection of
         spaces and contents below roof deck from water leakage.
         Roof decks or insulation shall never be left exposed
         overnight or during inclement weather.

1.06 WARRANTY

    A.   Contractor shall submit, before installation,
         certification from the producer of slate shingles that
         the Contractor has undergone training in the application
         of these shingles by the producer.

    B.   The Contractor shall provide a two-year warranty against
         leaks, faulty material and workmanship.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Procedure 07315-02-S contains an extensive list of slate
         roofing manufacturers for reference.

2.02 MATERIALS

    NOTE:  See 07315-01-R or 07315-03-R for specific materials and
    equipment required for slate repair and replacement.  Other
    general requirements relating to materials are listed below.

    A.   Material and Workmanship:  Slate shall conform to the
         following requirements:

         1.   Unless otherwise specified, surfaces shall be of
              reasonably smooth cleavage.

         2.   Slate shall be free from knots or knurls that would
              lessen the durability or weather tightness of the
              finished work.

         3.   Unless otherwise specified, slate shall be
              rectangular, with straight cut edges.

         4.   Unless otherwise specified, corners shall be
              reasonably full on exposed edges, with no broken
              corners on covered ends that would diminish the
              nailing strength or weather tightness.

         5.   Unless otherwise specified, the thickness shall be
              approximately three-eighth inch.

         6.   Flatness - The maximum bend shall not exceed one-
              eighth inch in 12 inches.

         7.   Unless otherwise specified, holes shall be machine-
              punched for 3-inch double lap.

    B.   General Requirements:

         1.   Slate shall be whole and clean. Not more than 2
              percent of broken slate will be accepted.

         2.   All slate shall be hard, dense, sound rock, punched
              for two nails each. No cracked slate shall be used.
              All exposed corners shall be practically full. No
              broken corners on covered ends which sacrifice
              nailing strength or the laying of a water-tight
              roof will be allowed.

    C.   Detail Requirements:

         1.   Color: To match existing or original and as
              approved by RHPO.

         2.   Strength:  The average modulus of rupture across
              the grain shall not be lower than 9,000 pounds per
              square inch.

         3.   Absorption: The maximum absorption shall be - Grade
              A -- 0.08%.

         4.   Acid Resistance: The slate shall, under the acid
              test, show no softening to an average depth greater
              than - Grade A -- 0.002 inch.

    D.   Methods of Sampling, Inspection and Tests:

         1.   The inspection of the slate may be made at the
              discretion of the Government either before or after
              delivery.

         2.   Samples for test, when required, shall be selected
              by the Inspector and shall be representative of the
              material. At least one sample of slate shall be
              selected from each carload or fraction thereof.
              Additional samples may be taken for test at any
              time or place at the discretion of the Government.

         3.   Absorption Test: The specimen shall consist of a
              square or rectangular slab not less than 4 inches
              on any side, cut from the slate shingle so that the
              saw cut is nowhere nearer than 1 inch to the
              sheared edge.



PART 3---EXECUTION

3.01 EXAMINATION

    A.   Examine substrate surfaces to receive slate shingles and
         associated work and conditions under which roofing will
         be installed. Do not proceed with roofing until
         unsatisfactory conditions have been corrected in a manner
         acceptable to Installer.

         1.   Verify that flatness and fastening of wood roof
              decks are securely fastened with no projecting
              fasteners and with no adjacent units in excess of
              1/16-inch out of plane. Pull out or drive home
              projecting fasteners.

    B.   Condition of Surfaces: Decks to which roofing system is
         to be applied shall be sound and dry, clean, smooth and
         free from projections. Application of roof system
         components shall not progress when there is ice, frost,
         surface moisture, or dampness, visible on the roof deck.
         Deck shall be thoroughly broomed clean, including within
         flutes.

    C.   Replace any boards of the wood roof deck if shown to be
         weak structurally, rotted, splintered or broken with
         treated boards.

3.02 PREPARATION

    A.   Roof removal is to commence in the center of areas to be
         removed and to proceed outward to the edge of the areas
         to be removed.

    B.   Any disintegrating, wet or failed material shall be
         removed and replaced.

    C.   Removed roofing, insulation, flashing and masonry will be
         removed from the roof immediately without allowing
         accumulation of piles of trash. Tossing of any trash,
         tools or any objects from roof to any areas below,
         including from one roof level to another, is expressly
         prohibited.

    D.   Removed materials shall become the property of Contractor
         and shall be removed from the site. Debris and scrap
         shall be removed from the work area daily.

    E.   Temporary Roof Installation:

         1.   If adverse weather conditions require protection of
              exposed deck, install 6 mil polyethylene sheets
              horizontally, shingling, from top to bottom. Staple
              and tape all joints and edges.

         2.   Remove temporary roof completely prior to
              installation of permanent roofing system.

                         END OF SECTION