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  • Sample report of a structural investigation - Improper steel erection


    BUILDING INVESTIGATION

    Customer Name: Owner

    Project Name: Facility

    Project Location:

    Submitted to: Owner

    Submitted by Thomas R. Price P.E., of Structural Solutions LLC, a licensed professional engineer.


    I. Purpose of Investigation:

    At the request of Owner, Thomas R. Price P.E., of Structural Solutions LLC inspected the Facility in the attempt to determine whether the installation of roof and wall materials has been done in accoDrance with manufacturer guidelines and appropriate quality of workmanship.


    II. Description of Building:

    The building in question is a metal building originally manufactured by a metal building manufacturer. It was located at a different site, then disassembled and shipped to the new site where it was re-erected. The wall and roof sheathing was not salvaged - new wall and roof systems were utilized. Materials and installation of the walls and roof was provided by contractor. The manufacturer of the wall and roof materials is a leading producer of metal building components.

    The building is 70’ wide by 120’ long, with a symmetric gable roof. Roof slope
    is approximately 1:12 on each side of the ridge. The roof is a 24” wide galvalume
    standing seam system. Roof panels are continuous from eave to ridge with no intermediate panel lap splices. Panel attachment clips are the “fixed” type. Frame spacings are 24’ and 22’-6”. Purlins are cold-formed zees with approximately 5’ spacings.

    A stud framed one story office building extends along the NE end of the main
    building, around the SE corner, and part way along the SE side of the main
    building. This building’s roof meets the main building NE and SE walls approx-
    imately 6’ below the main building rake and eave.


    III. History:

    Shortly after the roof was installed, leaks in the ridge area became evident, as well as
    at least one leak along the NW eave, and one leak in the south corner.

    A second, wider ridge cap was installed over the first in an attempt to prevent leakage in
    the ridge area.


    IV. Referenced Documents:

    Manufacturer’s Instructions on installation of the roof system.


    V. Field Observations and Notes:

    The inspection took place between 10:00 am and noon. Weather was partly cloudy, with a temperature of approximately 60 F. Present on the site was the owner, a representative of the contractor, and Mr. Price. Our comments relative to the inspection of the main building are listed below.

    It must be noted that all details and materials of construction are not readily visible
    and verifiable without some disassembly of the ridge and eave details. No disassembly
    other than removal of a small section of ridge pan was done during the inspection.

    1) Excessive distortion and oil canning type deformations were observed in
    many of the roof panels. It was noted that the roof has undergone a lot of traffic.

    2) Only one screw has been installed between the minor ribs of the roof panels at the
    attachment location to the eave plate. AccoDring to the component supplier, two screws (#5 &
    #6) are required, and each should be located adjacent to the minor rib. See also p.38.

    3) The roof panels do not extend adequately past the edge of the sculptured eave trim.
    Caulk has been applied between the roof panels, and the eave trim. This caulk does not
    remedy the intent of the design which is to ensure that water runs off the panels over,
    not onto, the eave trim. Ref: component supplier installation manual. Water can pool just upslope of the caulk, and siphon back up under the roof panel. A narrower eave trim is a possible solution.

    4) At some panels, screws have been installed through the panel near the ridge, just
    downslope of the outside closures. These screws are not specified in the component supplier details,
    and since they directly penetrate the building envelope, they contradict the primary
    intent of a non-through fastened roof. These fasteners also tend to inhibit expansion
    and contraction of the panels.

    5) The fasteners described in item 4 are in the same pattern as the standaDr pre-punched
    holes. If these are indeed the pre-punched holes, then the outside closures have been
    installed too far upslope. Since the pre-punched holes are very close to the end of
    the panel, the outside closures may be partially or completely off the panels. This
    assumes that the holes have been properly located in fabrication. Inspection from
    below. with ridge pan removed revealed an outside closure located aside, and not
    on top of, its mastic strip. Ref: component supplier installation manual.

    6) Wide (3/4” to 1”) beads of caulk/mastic have been applied between the outside clo-
    sures and the roof panels, downslope of the closures. This material is not specified in
    the component supplier installation manual, and should not be necessary if the outside closures are properly
    installed with double bead tape sealer between the closure and the panel. Ref: component supplier installation manual.

    7) Items 3,4,5, and 6 indicate that the roof panels may be too short. The installation manual
    dictates that the panels must overhang the eave strut by the thickness of the wall
    covering plus 4-3/8”, and the ridge purlin web by 7”. Ref: installation manual.
    The panel length should be verified to be as per installation manual guideline. The installation manual states that the purlins at the ridge be located exactly as detailed, and that any
    mislocation can cause fouling. We suspect that this could be the cause of the ridge
    leaking problems, and a thorough investigation of the ridge detail be undertaken.
    This involves some disassembly of the region to the extent that all details specified by
    the component supplier have been complied with. A similar investigation of the eave regions should be
    undertaken.

    Any deviations from component supplier installation procedures should be verified to be
    approved by the component supplier.

    8) The modularity (main rib spacing) of the panels varies from the target 24” by
    as much as 1/2”. Modules of 24-1/2” were measured in various locations. This exces-
    sive panel stretching is causing the main ribs to flare out at the ends, which in turn
    causes the excessive gap between the inside (eave) closures and the panel. The gap this
    is likely causing at the ridge is not visible due to the wide bead of mastic described in
    item 6.

    The installation manual indicates that fasteners into the outside closures are not to be installed
    as roof panels are laid. This is questionable, as fastening these as panels are laid will
    help maintain modularity.

    9) The panel ends at the eaves exhibit noticeable stairstepping. This, combined with the
    poor modularity indicate that problems were encountered in maintaining panel square-
    ness. Panel width adjustment techniques are described in installation manual . These pro-
    cedures are intended to make minor adjustments as the roof is laid. More detailed
    measuring of modularity should be done to determine if excessive adjustments were
    made during installation.

    The building must be verified to be square and true prior to roof installation. Adjusting
    for out of plane substructure is described in installation manual . Inquiries to the installers
    should be made in regaDr to what measuring was done to assure building squareness
    and substructure levelness prior to roof installation. Ref: installation manual

    10) Approximately 12 panels in the NW region of the roof show damage from crane
    straps. Some corrosion appeared to be forming in these areas.

    11) The second ridge cap did not appear to be fastened in a manner secure enough to
    withstand Code required wind loads. Documentation of design should be furnished
    for owner inspection.

    12) Roof panel termination at the rake ends have not been installed per manufacturer
    instructions. See Variable termination flashing, p.26, 36. It appears that the last
    panel has been cut longitudinally, and bent up under a counterflashing member.
    No cutting of panels is prescribed by installation manual details.

    13) Screw holes, or possibly panel end pre-punched holes plugged with silicone type
    caulk were observed in some locations at the ridge and eave.

    14) Five exterior floodlights have been installed , with anchorage and electric run
    through the wall panels. These openings should be sealed for weather tightness.

    15) 3070 door on NW side has uneven jambs. This should be repaired to assure weather
    tightness.

    16) Wall panel at transition to masonry does not appear to have adequate anchorage.
    Attaching this panel to masonry should be considered.

    17) Office roof to main building high eave parapet: The main building wall panel
    closures should be present, and ideally should have mastic tape sealing them,
    and helping to hold them in place under pressures from ice build-up.


    VI. Conclusions:

    The apparent deviations from the manufacturer details at the ridge may be the cause of
    the first ridge cap leak problems.

    There is evidence to suspect that the panels are too short too meet the installation manual prescribed
    overhangs of eave plate and ridge purlin, thereby compromising the integrity
    and weather tightness of the roof system.

    The second ridge cap does not appear to be fastened adequately.

    Roof panels marred and distorted by apparent heavy traffic should be inspected by
    the manufacturer to determine their warrentability.

    Holes in roof panels plugged with caulk is typically considered unacceptable for a
    non through fastened standing seam roof.
    VII. Recommendations:

    An investigation involving some disassembly of the eave and ridge regions should be
    undertaken to verify all details, dimensions, and materials are in place as specified
    by the manufacturer.

    It is recommended that the panel length be verified to be in accoDrance with manu-
    facturer guidelines, as part of the above disassembly/investigation.

    It is recommended that the ridge caps be removed and replaced with materials
    and details per the manufacturer’s procedures, or approved retrofit procedure, unless
    satisfactory design documentation can be provided, regarding structural integrity
    and weather tightness.

    Specific remedy procedures should be designed based upon the information gathered
    from the ridge/eave investigation, and reviewed with the manufacturer and this office
    prior to any further work proceeds on the roof. The second ridge cap may or may not
    be deemed appropriate based upon the investigation.

    The flaring of main ribs at the eave are excessive to the point that weather tightness
    cannot be assured. These areas must be remedied such that the standaDr inside
    closure fits properly, or other solution be devised and approved by the manufacturer.

    The areas damaged by the crane straps should, as a minimum be treated to prevent
    localized corrosion. Appropriate procedure should be discussed with manufacturer.



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Structural Solutions LLC
1200 Troon Ct. SE
Grand Rapids, MI 49546
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