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Historic Preservation - Technical Procedures

Spectitle:

Removing And Replacing A Built-Up Asphalt Roof

Procedure code:

0751103R

Source:

Federal Bldg/Us Courthouse, Eau Claire, Wi - Chicago, Il

Division:

Thermal And Moisture Protection

Section:

Built-Up Asphalt Roofing System

Last Modified:

02/24/2012

Details:

Removing And Replacing A Built-Up Asphalt Roof



REMOVING AND REPLACING A BUILT-UP AS= PHALT ROOF


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on the removal of
         deteriorated built-up roofing, insulatio= n, flashings,
         wood blocking and equipment pads, and replacing with new
         built-up roofing.

    B.   For additional guidance on inspecting and repairing flat
         roof systems, see 07500-01-S, 07500-02-S, 07510-01-S and
         07511-02-R.

    C.   Safety: The employer is expected to work in accord= ance
         with OSHA standard.

    D.   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 REFERENCES

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

1.03 DEFINITIONS

    A.   Roofing System:  An assembly of related compo= nents
         consisting of the following:

         1.   Preformed above deck roof insulation.

         2.   Built-up bituminous roofing.
         3.   Built-up base flashings and seals.

    B.   Non-Nailable Substrate:  Any substrate for built-up
         roofing which is not intended to receive and hold
         mechanical fasteners such as cast-in-pla= ce concrete,
         precast concrete, block or board insulat= ion, or
         lightweight insulating roof fill.

    C.   Bitumen:  Coal-tar pitch or asphalt.

    D.   Built-Up Flashing:  Any non-metallic bitumino= us flashing,
         including fabric and felt, applied with hot-mopped
         asphalt or cold process bituminous plast= ic flashing
         cements.

1.04 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.

         1.   For asphalt bitumen, provide label on each
              container or certification with each load of bulk
              bitumen, indicating flash point (FP), finished
              blowing temperature (FBT), softening point (SP) and
              equiviscous temperature (EVT).

    B.   Shop Drawings - Tapered Insulation: Submit shop drawings
         for the tapered insulation system. Shop drawing shall
         include plan layouts having high point and low point
         dimensions. Details shall be provided which show
         clearances at base flashings, counterfla= shings, fascias,
         copings, curbs, etc.

    C.   Samples - Aggregate Surfacing: Submit 3-lb. Samples of
         aggregate surfacing material, flashings, insulation,
         fasteners, roofing cement and roofing membrane.

    D.   Design Data/Test Reports/Certificates:

         1.   List of Materials:  Furni= sh, with the certificates,
              a list of materials propo= sed for use in the roof
              system, including name of manufacturer, for
              approval.

         2.   Certificates for Bituminous Materials:  Furnish the
              following certification, in triplicate, endorsed by
              the built-up bituminous roofing materials
              manufacturer:

              a.   That all materi= als in the roofing system are
                   chemi= cally and physically compatible.

              b.   That the materi= als meet all the specified
                   requi= rements, referenced specifications,
                   stand= ards and tests.

         3.   Certificates for Insulation:  Furnish the following
              certifications, in tripli= cate, from the
              manufacturer of the roof insulation:

              a.   Certificates, signed by the Contractor and the
                   insul= ation manufacturer, stating that
                   insul= ation, including cant strips, conform to
                   speci= fied requirements, the thickness for the
                   speci= fied "U" factor, and that the materials
                   are proper for use on this project and in
                   conju= nction with the specified roof system.

         4.   Certificates for Materials Over Different Deck
              Types:  Furnish evidence of approved laboratory
              labeling, listing or certificates attesting that
              materials and method of installation over various
              deck types meet specified test procedures and
              classification standards.=

    E.   Manufacturer's Instructions/Field Reports: Submit daily
         softening point test reports on samples of asphalt used
         on project, taken at beginning of each day's work and at
         2-hour intervals during course of the work thereafter.
         Test by Ring and Ball Test, ASTM D2398, or similar
         recognized test method. Submit samples to independent
         laboratory for testing or perform tests in field, at
         Contractor's option.

    F.   Warranty - Manufacturer's Certification, Bulk Bitumen:
         Submit manufacturer's certification indicating that bulk
         bituminous materials (if any) delivered to project comply
         with required standards. Include quantit= y, statistical
         and descriptive date for each product. Submit certificate
         with each load before it is used.

         1.   Include continuous log showing time and temperature
              for each load of bulk bitumen, indicating date
              obtained from manufacture= r, where held and how
              transported prior to final heating and application
              on roof.

1.05 QUALITY ASSURANCE

    A.   Manufacturer Qualifications: Provide primary produ= cts,
         including each type of roofing sheet (felt), bitumen,
         composition flashings and vapor retarder, 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 manufact= urer of primary
         products for use with roofing system specified.

    B.   Installer Qualifications: A single Installer (&quo= t;Roofer")
         shall perform the work of this section; and shall be a
         firm with not less than 5 years of succe= ssful experience
         in installation of built-up roofing systems 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 manufa= cturer of built-up roofing
              system certifying that installer is approved by
              manufacturer for installa= tion 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 superv= isor/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.

    C.   Pre-Application Roofing Conference: Approximately two
         weeks prior to scheduled commencement of built-up roofing
         installation and associated work, meet at project site
         with Installer, installer of each compon= ent of associated
         work. Lifters of roof-top units and other work in and
         around roofing which must precede or follow roofing work
         (including mechanical work), the Contrac= ting Officer,
         Government, roofing system manufacturer's representative,
         and other representatives directly conce= rned with
         performance of the work including (where applicable)
         Government's insurers, test agencies, and governing
         authorities. Record (Contractor) discuss= ions 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 requirem= ents (drawings,
              specifications and other contract documents).

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

         4.   Review and finalize constructi= on 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 mandato= ry requirement).

    D.   Compatibility:  All materials provided shall be
         compatible with each specified component of the built-up
         roofing system.  All materials shall be approved by the
         manufacturer of the roofing materials for use with this
         system.

    E.   UL Listing: Provide built-up roofing system and component
         materials which have been tested for application and
         slopes indicated and are listed by Under= writers'
         Laboratories, Inc. (UL) for Class A external fire
         exposure.

         1.   Provide roof covering materials bearing
              Classification Marking (UL) on bundle, package or
              container indicting that materials have been
              produced under UL's Class= ification and Follow-up
              Service.

    E.   FM Listing: Provide built-up roofing system and component
         materials which have been evaluated by Factory Mutual
         System for fire spread, wind-uplift, and hail damage and
         are listed in "Factory Mutual Appro= val Guide" for Class
         I construction.

         1.   Provide roof covering materials bearing FM approval
              marking on bundle, package or container, indicating
              that material has been subjected to FM's
              examination and follow-up inspection service.

    F.   Condition of Surfaces:  Decks to which roofing system is
         to be applied shall be sound, dry, inclu= ding flute
         openings of metal decks, 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.  The Contractor
         shall be responsible for damage to the deck or structure
         due to his trafficking across same, or to loads imposed
         by him in any form.  Evidence shall be submitted that
         roof deck surfaces, and all slopes to roof drains and
         outlets have been checked, and are appro= ved, for
         installation of the roof system before installation of
         any roofing is started.  Joints in deck shall be sealed
         as necessary to prevent drippage of bitumen into the
         building or down exterior walls.  

1.06 DELIVERY, STORAGE AND HANDLING

    A.   Packing and Shipping:  Roofing materials shall be
         delivered with manufacturer's labels and seals intact and
         legible.  Materials delivered in bulk shall be
         accompanied by a certificate from the manufacturer,
         stating that the material complies with the specified
         requirements.


    B.   Storage and Protection:

         1.   Store and handle roofing sheets in a manner which
              will ensure that there is no possibility of
              significant moisture pickups. 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.

         2.   Use forklift cradle to lift insulation pallets to
              roof deck; do not use sling. No more insulation
              shall be stored on the roof than can be used in one
              day.

         3.   Felt rolls and insulation piles 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.

    C.   Mineral Aggregate: The aggregate shall be delivered in
         dry condition. If yard gravel is wet, it may be oven
         dried at an asphaltic batching plant. Aggregate piles at
         site shall be completely covered with tarpaulins.

1.07 PROJECT/SITE CONDITIONS

    A.   Environmental Requirements:  

         1.   Proceed with roofing work only when existing and
              forecasted weather condit= ions will permit work to
              be performed in accordance with manufacturer's
              recommendations and warra= nty requirements.

         2.   Roofing system materials shall not be applied
              during rain or snow.  Applications may be continued
              in cold weather subject to the following
              requirements:

              a.   Comply with all provisions of these and the
                   manuf= acturer's specifications.

              b.   Do not overheat bitumen to compensate for
                   rapid chilling.

              c.   When temperature drops below 40 degrees F.,
                   use insulated buckets to carry hot bitumen;
                   mop manually no further than 5 feet in front
                   of felt rolls and immediately unroll felt over
                   bitum= en; immediately apply top pour of bitumen
                   and aggregate before stored head dissipates in
                   the membrane.

    B.   Temporary Protection: Contractor shall be responsi= ble 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. Temporary
         membranes with open seams, such as plast= ic or loose
         roofing felts, shall not be used to provide protection.

1.07 WARRANTY

    A.   Special Project Warrantee: Submit 2 executed copies of
         standard 2 year "Roofing Guarantee&= quot; on form included at
         end of this section, covering work of this section
         including roofing membrane, composition flashing, roof
         insulation, vapor barriers (if any), and roofing
         accessories, signed and countersigned by Installer
         (Roofer) and Contractor.

    B.   Manufacturer's Warranty: Submit executed copy of roofing
         manufacturer's standard "Limited Service Warranty"
         agreement including flashing endorsement, signed by an
         authorized representative of built-up roofing system
         manufacturer, or on form which was publi= shed with product
         literature as of date of contract docume= nts, for the
         period of 10 years after date of substan= tial completion.

    C.   Defects:  Conditions which may be detrimental to
         completion or performance of specified work shall be
         reported in writing to the Contracting Officer prior to
         commencing such work and such work shall not start until
         defects have been corrected.  No claim by the Contractor
         concerning defects will be allowed if made after starting
         work.


PART 2---PRODUCTS

2.01 MATERIALS

    A.   Insurance and Code Requirements: Provide materials=
         complying with governing regulations, and which can be
         installed to comply with the following:<= br>
         1.   Factory Mutual requirements for "Class I" or
              "Noncombustible,&quo= t; including zoned wind resistance.

         2.   Underwriter's Laboratories "Fire Classified" and
              "Class 60" wind uplift resistance.

    B.   All material used shall be asbestos free.

    C.   Temporary Roofing Membrane: 2 plies perforated No. 15
         asphalt saturated organic felt complying with ASTM D226,
         Type I, set in and glaze-coated with hot mopping of ASTM
         D312, Type III asphalt.  

    D.   Vapor Barrier (Retarder):

         1.   Bituminous Vapor Barrier (Reta= rder): 2 plies
              perforated No. 15 asphalt saturated organic felt
              complying with ASTM D226, Type I, 1st layer nailed,
              2nd layer set in and glaze-coated with ASTM D312,
              Type III Asphalt.

    E.   Roof Insulation:

         1.   Tapered Rigid Board Insulation: Boards shall be 24"
              wide, the tapering system composed of boards having
              a slope of =AC" and =AB" per foot. Installation shall
              be in accordance with manufacturer's
              specifications, using type III asphalt. Junctures
              at valleys shall be mitred (not laced). Contractor
              shall furnish roof plan drawings showing all slopes
              and valleys details. Otherwise same as paragraph
              "2" below.

         2.   Glass-Fiber Board Roof Insulat= ion: Rigid glass-
              fiber boards of thickness= es indicated, with k-value
              of 0.27 at 75 F (24 C), with integrally bonded top
              covering of asphalt-impre= gnated felt or Kraft
              paper; comply with ASTM C726; manufacturer's
              standard sizes except as otherwise indicated.
              Provide for flat and tapered installation.

    F.   Built-Up Roof Membrane System:

         1.   Nailable-Deck Asphalt/Glass-Fi= ber/Aggregate Roofing
              (NAGA-BUR): Provide built= -up, aggregate-surfaced
              roof system with asphalt bitumen and glass fiber
              ply felts for lay-up as indicated:

              a.   Sheathing Paper: Single-ply of 5-pound rosin-
                   sized sheathing paper.

              b.   Ply Felts: 4 plies of asphalt-impregnated
                   glass= -fiber felts, complying with ASTM D2178,
                   Type IV.

              c.   Interply Bitume= n: Roofing asphalt, complying
                   with ASTM D312, Type III.

              d.   Comply with NRCA Roofing and Waterproofing
                   Manua= l, Specification Plate No. 32 - NAGA,
                   Diagr= am A.

         2.   Insulated-Deck Asphalt/Glass-F= iber/Aggregate
              Roofing (IAGA-BUR):

              a.   General: Provide built-up aggregate-surfaced
                   roof system with asphalt bitumen, and plies
                   glass= -fiber mats for lay-up as indicated.

              b.   Primer: asphalt cut-back primer, complying
                   with ASTM D41.

              c.   Ply Felts: 4 plies of asphalt-impregnated
                   glass= -fiber mats, complying with ASTM D2178,
                   Type 2178.

              d.   Bitumen: Roofing asphalt, complying with ASTM
                   D312, Type III.

              e.   Comply with NRCA Roofing and Waterproofing
                   Manua= l, Specification Plat-#42- IAGA, Diagram
                   A.

    G.   BUR Edge/Penetration Materials:

         1.   Roofing Cement: Asphaltic cement; comply with ASTM
              D2822. Asphaltic cement shall be reinforced with
              non-asbestos fibers, imparting positive properties
              equal to the asbestos fibers. The Contractor shall
              submit to the Contracting Office the following
              information from the roofing cement manufacturer:
              Reports of laboratory performed weatherometer
              tests, indicating an expected life span for the
              fibrous, non-asbestos cement equal to the span for
              ASTM conforming asbestos fiber cement similarly
              tested; in No case shall it be less than a 15 year
              span. Roof work shall not proceed until such Test
              Reports are submitted.

         2.   Glass Fiber Fabric: 1.5-lb. (min.) sheet, of woven
              glass fiber, impregnated with asphalt (ASTM D1668).

         3.   Coated Felt: 26-lb. Sheet, of asphalt-organic felt
              coated with asphalt both faces, "No. 30 Coated
              Organic Felt."

         4.   Lead Flashing: 4-lb. Sheet of common desilverized
              pig lead.

         5.   Modified Bitumen shall be modified by the addition
              of styrene-butadiene-styr= ene (SBS), reinforced. It
              shall be mopped on.

    H.   Miscellaneous Materials:

         1.   Surfacing Aggregate: Clean, water-worn opaque
              gravel complying with ASTM D1863.

              a.   Where ASTM D1863 aggregate is not available,
                   provi= de aggregate complying with gradation
                   sizes 6, 7, and 67 of ASTM D448, provided that
                   moist= ure content by weight is 3% or less and
                   aggre= gate meets other requirements of ASTM
                   D1863= .

         2.   Wood Member's Units: Provide wood pressure treated
              with water-borne preserva= tives for above ground use
              (AWPB LP-2).

         3.   Insulation Joint Tape: 6" or 8" wide coated glass
              fiber mat.

         4.   Mastic Sealant: Polysiobutylene (plain or
              bituminous modified), nonhardening, nonmigrating,
              nonskinning and nondrying= .

         5.   Asphaltic Primer: Comply with ASTM D41.

         6.   Fasteners: Provide industry-st= andard types of
              mechanical fasteners for BUR system work, tested by
              manufacturer for required pull-out strength where
              applicable and compatible with deck type and
              roofing products used. Provide either 1" diameter
              nail heads or 1-3/8" diameter x 30-gauge sheet
              metal caps for nails used to secure base sheets,
              felts, or insulation boards of roofing system.
              Material shall be galvani= zed or stainless steel.

2.03 FABRICATION OF SHEET METAL ACCESSORIES:

    A.   SMACNA and NRCA Details: Conform work with details shown,
         and with applicable fabrication requirem= ents of
         "Architectural Sheet Metal Manual&q= uot; by SMACNA. Comply with
         installation details of "Roofing and Waterproofing
         Manual" by NRCA and Section 07600.<= br>
    B.   Prefabricate units as indicated, or provide standa= rd
         manufactured units complying with requir= ements; fabricate
         from sheet metal indicated or, if not otherwise
         indicated, from copper.

    C.   Provide 4" wide flanges for setting on BUR membrane with
         concealment by composition stripping as per General Notes
         on the Drawings.

    D.   Fabricate work with stitch riveted soldered joints and
         seams; except where joint movement is necessary, provide
         1-inch-deep interlocking hooked flanged filled with
         mastic sealant.

    E.   Fabricate gravel "rings" and aggregate divider strips
         with 1" high standing leg of folded sheet metal, notched
         form top with 5/8" V notches. Space notches 3" o.c. where
         strip intersects flow of water on roof. Fabricate rings
         to sizes and shaped indicated (but not less than 36"
         square).

    F.   Fabricate penetration sleeves with minimum 8" high stack,
         of diameter 1" larger than penetrat= ing element. Counter
         flashing is specified as work of another section of these
         specifications.

PART 3---EXECUTION

3.01 EXAMINATION

    A.   Verification of Conditions:

         1.   Examine substrate surfaces to receive built-up
              roofing system and associ= ated 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.<= br>
         2.   Verify that deck is securely fastened with No
              projecting fasteners and with No adjacent units in
              excess of 1/16" out of plane.

    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.
         Joints in deck shall be sealed as necess= ary to prevent
         drippage of bitumen into the building or down the
         exterior walls. Deck shall be thoroughly broomed clean,
         including within flutes.

3.02 PREPARATION

    A.   General:  This work includes, without limitat= ion, removal
         of existing roofing, insulation, flashin= gs, wood blocking
         and equipment pads in areas shown on the drawings.

         1.   Any exposed surface of the precast concrete units
              shall be dried of water and cleaned of loose
              material.

         2.   Any disintegrating, wet or failed material shall be
              removed.

         3.   Any cracks, minor holes, or other surface
              imperfections of the precast concrete units
              supporting surface shall be repaired as per
              Drawings General Notes.
         4.   Removed roofing, insulation, and flashing will be
              removed from the roof immediately without allowing
              accumulation of piles of trash. Tossing of any
              trash, tools or any objec= ts from roof to any areas
              below, including from one roof level to another, is
              expressly prohibited.

         5.   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.

    B.   Protection: Protect other work from spillage of built-up
         roofing materials, and prevent liquid materials from
         entering or clogging drains and conducto= rs.
         Replace/restore other work damaged by installation of
         built-up roofing system work.

    C.   Surface Preparation:  Before any tearoff of the existing
         BUR systems, remove all gravel with a mechanical broom
         and a mechanical vacuum.

3.03 ERECTION, INSTALLATION, APPLICATION    

    A.   Fire and Wind Resistance Compliance: Install BUR system
         for compliance with the following:

         1.   Factory Mutual requirements for "Class I" or
              "Noncombustible,&quo= t; including zoned wind resistance
              as specified by FM.

         2.   Underwriter's Laboratories "Fire Classified" and
              "Class 60" wind uplift resistance.

    B.   Coordinate the installation of insulation, roofing=
         sheets, flashings, stripping, coatings and surfacings, so
         that insulation and felts are not exposed to
         precipitation nor exposed overnight. Provide cut-offs at
         end of each day's work. To cover exposed felts and
         insulation with a course of coated felt with joints and
         edges sealed with roofing cement. Remove cut-offs
         immediately before resuming work. Glaze coat installed
         ply-sheet courses at end of each day's work where final
         surfacing has not been installed.

    C.   Asphalt Bitumen Heating: Heat and apply bitumen in
         accordance with equiviscous temperature method ("EVT
         Method") as recommended by NRCA. Do not raise temperature
         above minimum normal fluid-holding tempe= rature necessary
         to attain EVT (+25 F or 40 C at point of application)
         more than one hour prior to time of application. Discard
         bitumen which has been held at temperatu= re exceeding
         finished blowing temperature (FBT)for a period exceeding
         three hours. Determine flash point, finished blowing
         temperature and EVT of bitumen, either by information
         from bitumen producer or by suitable tests, and determine
         maximum fire-safe handling temperature and do not exceed
         that temperature in heating bitumen; but in No case heat
         bitumen to a temperature higher than 25 F (14 C) below
         flash point. For aggregate-surfaced pour coats of
         bitumen, limit application temperature to minimum
         required for proper embedment of aggrega= te and maximum
         which will permit retention of a coating of weight
         required (depends on slope of surface). Keep kettle lid
         closed except when adding bitumen.

         1.   Contractor shall maintain not less than 2 testing
              thermometers similar to Aeroil dip bimetallic type
              with a dome faced gauge registering 50 F at the
              kettle site at all times. Built-in asphalt heating
              plant thermometers shall not be used in lieu of
              testing thermometers.

         2.   Heating of Bitumen:

              a.   Solid bitumen shall be broken open on a clean