REPORT FINDINGS @ ST PETER'S CHURCH 08/28/2018 Z_2 ST
EN 1 STA 5565 Glenridge Connector,Suite 900 TOLL-FREE 888.782.3473
Atlanta,GA 30342 envistaforensics.conn
FORENSICS
REPORT OF FINDINGS
ST. PETER'S CHURCH
Church Insurance Company File No: 36629
Envista Matter No: MAT-82717-D8J7
REPORT DATE- August , 2018
JOSEPH M. ti
o YARBOROUGH
STRUCTURAL
o No 48888
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8/30/18
Prepared For:
Ms. Christine DeBow
Church Insurance Company
19 E 34th St
New York, NY 10016
cdebow@cpg.org
CERTAINTY IN AN UNCERTAIN WORLD
PT&C Forensic Consulting Semites,P.A.I TX Firm Registiotlon#F-19410 I NC firm Registration#C-2837 I FL Certificate of Authorization#27066
E N 1 STA Page 2 of 6
Envista Matter No: MAT-82717-D8J7
F O R E N 5 1 C 5 Church Insurance Company File No: 36629
BACKGROUND
On May 30 and August 3, 2018, Envista Forensics (Envista) inspected the St. Peter's Church located at
24 Saint Peter Street in Salem, Massachusetts.The church consisted of multiple interconnected masonry
structures which housed the sanctuary, the fellowship halls, and associated facilities. The main portion
of the church, which housed the sanctuary, and comprised the subject of Envista's investigation,
consisted of a rectangular stone masonry structure covered with a hipped roof clad with asphalt
composition shingles. Reportedly, the church was constructed in the 1830s. For the purposes of
discussion within this report, the front of the church was considered to be facing west (Attachment A,
Photograph 1).
Reportedly, the subject church sustained damage during the 2017-2018 winter season. Accumulations
of ice and snow on the roof reportedly damaged the asphalt shingle roofing, and caused water to intrude
and damage the plaster ceiling overlying the sanctuary. Upon removal of the plaster ceiling, the Building
Official reportedly noted that some of the wood ceiling joist had failed, and required the ceiling framing
assembly to be inspected by a professional engineer.
PURPOSE
Church Insurance Company retained Envista to inspect the subject building's wood roof structure and
ceiling framing assembly, and to determine what measures would be required in order to rehabilitate the
framing assemblies such that they could support a new roof covering and a new gypsum board ceiling.
RECOMMENDATIONS
1. The existing wood decking throughout the subject building's roof structure should be progressively
removed and replaced in its entirety with 5/8-inch-thick wood structural panel sheathing. The new
asphalt shingle roofing and underlayment should then be installed in accordance with code
requirements.
2. The proposed 5/8-inch-thick gypsum board ceiling with a veneer plaster finish can be attached
directly to the existing wood strapping members which span between the existing ceiling framing
members, and the existing wood framing components throughout the ceiling framing assembly
do not require upgrading.
3. The dislodged 3x4 wood framing members near the northeast corner of the building's ceiling
framing assembly can be reattached to the supporting wood beam by way of Simpson A34 clip
angles or approved alternatives installed at each side of each of the dislodged connection.
4. All of the connections of the 3x4 wood framing members at the supporting 12x10 wood beams
throughout the ceiling framing assembly should be reinforced by way of Simpson A34 clip angles
or approved alternatives installed at each side of each connection.
5. The weight of new insulation installed atop the new ceiling assembly must be less than or equal
to the weight of the insulation removed during the demolition of the plaster ceiling assembly.
6. The connections of the roof and ceiling framing members at the bell tower, and potentially other
connections if damage is discovered, should be inspected by a licensed structural engineer after
their exposure during construction.
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Envista Matter No: MAT-82717-D8J7
FORENSICS Church Insurance Company File No: 36629
DOCUMENTS REVIEWED
The following documents and materials were reviewed as part of Envista's investigation:
1. American Society of Civil Engineers, Structural Engineering Institute. ASCE/SEI 7-10. Minimum
Design Loads for Buildings and Other Structures.
2. International Code Council. 2015 International Building Code, with Massachusetts Amendments
(780 CMR—9th Edition).
3. International Code Council. 2015 International Existing Building Code, with Massachusetts
Amendments (780 CMR—9th Edition, Chapter 34).
DISCUSSION
The subject building was covered by a hipped roof with slopes of approximately 7 units vertical to 12 units
horizontal. The north and south roof slopes formed a ridge at the roof centerline, whereas the east and
west roof slopes were bounded by hips extending from apexes at the ridge's respective ends. A pair of
wood trusses, built up from heavy timber members, spanned between the building's north and south
exterior walls and provided the primary support for the roof structure. The trusses were spaced
approximately 12 feet apart, and coincided with the ends of the ridge and the hip apexes.
The building's roof consisted of wood decking supported by timber rafters. The rafters spanned from the
building's eaves to the ridge member and hip rafters, and were supported intermediately by purlins which
spanned between the top chords of the trusses. The sanctuary featured a plaster ceiling supported by
wood lath which spanned between 4x6 wood strapping spaced at approximately 16 inches on-center.
The strapping members spanned between wood beams spaced at approximately 5 feet on-center, which
spanned between larger beams (approximately 12 inches wide by 10 inches deep) that spanned from
the east and west exterior walls to the bottom chords of the respective trusses. The wood strapping
between the trusses was supported by continuous north-south spanning 2x6 wood members which were
suspended by intermediate members spanning between the bottom chords of the respective trusses.
Proposed Repairs
Reportedly, the building's roof and ceiling sustained damage during the course of the 2017-2018 winter
months as a result of ice and snow accumulations on the roof and consequent intrusion of water. To
repair the damage, representatives of the church and their contractor resolved to remove and replace
the asphalt shingle roofing and ceiling in their entireties. Because the roof covering was supported on
wood decking with gaps exceeding those allowed by many asphalt shingle manufacturers (typically
manufacturers allow gaps up to 1/4-inch), the contractor intended to install plywood sheathing throughout
the respective roof slopes after the removal of the existing roof covering so as to provide a solid substrate
for the new roofing materials.Additionally, given the age and condition of the plaster ceiling and concerns
about future failures of the ceiling, the church representatives and the contractor resolved to replace the
plaster ceiling with a veneer plaster ceiling, consisting of a thin layer of plaster installed throughout the
bottom surface of a 5/8-inch gypsum board substrate. Accordingly, Envista reviewed the applicable
building code requirements for the proposed repairs.
Code Review
Envista conducted a review of the 2015 International Existing Building Code as amended by the State of
Massachusetts (IEBC) in order to determine compliance of the proposed work. The damage reportedly
E N 1 STA Page 4 of 6
FORENSICS Envista Matter No: MAT-82717-D8J7
Church Insurance Company File No: 36629
sustained to the building's roof and ceiling did not comprise substantial structural damage, as defined in
IEBC Section 202. Thus, according to IEBC Sections 403.4 and 606.2.2, the damaged elements could
be restored to their pre-damage state. However, because the roof covering and ceiling were to be
modified and improved beyond their pre-damage state, Envista determined that the proposed work
constituted alterations rather than repairs, and accordingly, were subject to the corresponding sections
of the IEBC. Specifically, under the IEBC's Work Area compliance method, the proposed modifications
to the roof covering and ceiling constitute Level 1 Alterations.
1. Roof Covering Replacement
The existing asphalt shingle roof covering is reportedly to be removed in its entirety, and a new asphalt
shingle roof covering is to be installed. As previously noted, church representatives and their contractor
proposed to install plywood sheathing atop the existing wood roof decking so as to provide a solid
substrate for the new roof covering. IEBC Sections 403.3 and 707.2 stipulates that the weight of new roof
coverings shall not increase the weight of the existing roof covering by more than 5 percent. Given that
the addition of a new 3/8-inch plywood substrate would increase the weight of the roof covering
significantly more than this threshold, the referenced code sections require all structural members
affected by the increased dead load to be strengthened, supplemented, replaced or otherwise altered as
needed to carry the increased gravity load required by the 2015 International Building Code(IBC)for new
structures.
Envista initiated an analysis of the roof structure with current code-prescribed snow loads and found that
many of the wood members would have to be upgraded as a result of the code requirements triggered
by the increased dead load imposed by the installation of a new plywood sheathing layer. Alternatively,
the existing wood decking can be removed and replaced with wood structural panel sheathing (i.e.
oriented strand board or plywood). Using this alternative, the weight of the roof assembly would undergo
a net decrease in dead load, which thereby eliminates the need to reinforce the existing roof structure.
After considering the available options presented by Envista, Church Insurance Company opted to
proceed with the removal of the roof decking and replacement with new plywood sheathing, in lieu of
upgrading the existing structural framing components.
The existing roof decking was supported by rafters spaced at 24 inches on-center. Accordingly, Envista
recommends replacing the existing 1-inch decking with 5/8-inch-thick wood structural panel sheathing
rated to supporting a ground snow load of 50 pounds per square foot. The decking should be removed
in small sections and replaced with wood structural panel sheathing in a progressive manner (e.g. no
more than 250 square feet of decking should be removed and replaced at a time) so as to preserve the
bracing to the roof structure afforded by the decking.
In summary, based on its analysis, Envista concluded that the existing wood decking throughout the
subject building's roof structure should be progressively removed and replaced in its entirety with 5/8-
inch-thick wood structural panel sheathing. The new asphalt shingle roofing and underlayment should
then be installed in accordance with code requirements.
It should be noted that the decision to replace the asphalt shingle roof covering in its entirety was made
by others. The damage sustained to the roof covering was reportedly limited to the west roof field, and
as such, less extensive repairs may be feasible. Replacing the roof covering on only that slope may
eliminate the need to remove the existing roof decking; however, Envista did not conduct analyses of
alternate repair scenarios.
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Envista Matter No: MAT-82717-D8J7
F O R E N S I C S Church Insurance Company File No: 36629
2. Ceiling Replacement
At the time of Envista's inspection, the plaster ceiling and wood lath had been removed and disposed of.
Inspection of the few remaining remnants of the plaster ceiling revealed that the plaster was
approximately 5/16-inch thick, as measured from the ceiling surface to the bottom surface of the lath
members. The lath consisted of 3/4-inch by 1-1/2-inch wood strips spaced approximately 5/16-inch apart.
As with increased dead loads associated with new roof coverings as outlined above, IEBC Sections 403.3
and 707.2 require any existing structural members which an alteration causes an increase in design
gravity load of more than 5 percent to be strengthened, supplemented, replaced or otherwise altered to
carry the increased gravity load required by the IBC for new construction. Accordingly, if the proposed
gypsum board and veneer plaster ceiling weighs less than 105 percent of the existing plaster and lathe
ceiling, no structural upgrades are required.
5/8-inch gypsum board with a 3/32-inch-thick plaster veneer weighs approximately 3.4 pounds per square
foot. Based on the thickness of the plaster ceiling material recovered during Envista's inspection, Envista
determined that the weight of the plaster and lathe was approximately 3.6 pounds per square foot. This
unit weight was based on specific weights of the plaster and lathe of 80 pounds per cubic foot and 35
pounds per cubic foot, respectively, and conservatively assumed that the keys of the plaster (i.e. the
portion of the plaster that protruded from the gaps between the lath) comprised rectangular protrusion
5/16-inch tall. Therefore, because the dead load imposed by the proposed gypsum board ceiling is less
than the dead load of the removed plaster ceiling, the IEBC does not require the existing structure to be
upgraded in order to support the new ceiling. Therefore, Envista concluded that the proposed 5/8-inch-
thick gypsum board ceiling with a veneer plaster finish can be attached directly to the existing wood
strapping members which span between the existing ceiling framing members, and the existing wood
framing components throughout the ceiling framing assembly do not require upgrading.
Additional Items
3. Envista's inspection revealed that a portion of the ceiling framing assembly located near the
building's northeast corner exhibited a sagging configuration. Inspection of the framing elements
revealed that the sagging configuration had developed as a result of the failure of the tenon
connections of the 3x4 wood framing members at their interfaces with the supporting 12x10 wood
beam. The wood proximate to the joist ends and the morticed beam pockets remained intact, and
as such, the dislodged 3x4 wood framing members near the northeast corner of the building's
ceiling framing assembly can be reattached to the supporting wood beam by way of Simpson A34
clip angles or approved alternatives installed at each side of each of the dislodged connection.
4. Envista's inspection of the ceiling framing assembly did not reveal additional failed connections.
However, in order to reduce the likelihood of similar failures in the future, Envista recommends
that all of the connections of the 3x4 wood framing members at the supporting 12x10 wood beams
throughout the ceiling framing assembly should be reinforced by way of Simpson A34 clip angles
or approved alternatives installed at each side of each connection.
5. The insulation throughout the ceiling framing assembly had been removed prior to Envista's
inspection. So-as not to increase the gross weight of the finished ceiling assembly as required by
the referenced sections of the IEBC, the weight of new insulation installed atop the new ceiling
assembly must be less than or equal to the weight of the insulation removed during the demolition
of the plaster ceiling assembly.
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FORENSICS Envista Matter No:MAT-82717-D8J7
Church Insurance Company File No: 36629
6. It was noted that the interface of heavy timber framing members at the bell tower, abutting the
west edge of the roof structure, exhibited deterioration which will likely require rehabilitation. The
connection was not fully accessible at the time of Envista's inspection, and as such, the
connection should be inspected after the overlying roof decking has been removed so that an
appropriate repair can be designed and implemented. Accordingly, the connections of the roof
and ceiling framing members at the bell tower, and potentially other connections if damage is
discovered, should be inspected by a licensed structural engineer after their exposure during
construction.
Selected photographs pertinent to this discussion have been included as Attachment A of this report.
CLOSURE
This report is for the exclusive use of our client and is not intended for any other purpose. Our report is
based on information made available to us at this time. Should additional information become available,
we reserve the right to determine the impact, if any, of the new information on our opinions and
conclusions and to revise our opinions and conclusions if necessary and warranted by the discovery of
additional information.
Envista Forensics
seph . Yarborough, P.E. Peer Review by:
Senior Project Engineer Brian C. Lindsey, P.E. (Colorado)
Senior Project Engineer
Attachment A: Photographs
EN 1 STA Envista Matter No: MAT-82717-D8J7
Church Insurance Company File No: 36629
FORENSICS
ATTACHMENT A
Photographs
Photographs taken during our inspection, which have not been included in this report, have been retained
in our files and will be made available to you upon your request. Note that the brightness and/or contrast
of some photographs may have been enhanced for purposes of clarity. Some photographs may be
cropped from their original sizes in order to emphasize a specific item or feature. No significant changes
to any photographs were made that would alter factual representations.
E 1 STA ews Matter No: MAT-82717-D@7
IF0R ■ Ns , cs Our Insurance Company File No: a6629
Photograph t
Wed and south exposures o subject building.
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Photograph 2
Overview U roof above sanctuary, as viewed from the northeast.
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EN 1 STA Envista Matter No: MAT-82717-D8J7
Church Insurance Company File No: 36629
F O R E N S I C S
Photograph 3.
Interior view of the sanctuary.
Photograph 4.
Interior view of the sanctuary.
E N 1 STA Envista Matter No: MAT-82717-D8J7
F o R E N S i C S Church Insurance Company File No: 36629
Photograph 5.
Overview of ceiling structure, as viewed from scaffolding.
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Photograph 6.
Overview of ceiling structure.
E N 1 STA Envista Matter No: MAT-82717-1)817
F o R E N SIC S Church Insurance Company File No: 36629
Photograph 7.
Dislodged ends of ceiling joists near northeast corner of building..
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Photograph 8.
Dislodged ends of ceiling joists near northeast corner of building.
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E N 1 STA Envista Matter No: MAT-82717-D8J7
F O R E N S I C S Church Insurance Company File No: 36629
Photograph 9.
Overview of roof structure.
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Photograph 10.
Overview of roof structure.
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E N V11 STA Envista Matter No: MAT-82717-D8J7
FORENSICS Church Insurance Company File No: 36629
Photograph 11.
Overview of roof structure.
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Photograph 12.
Typical gaps between roof decking boards.
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EN 1 STA Envista Matter No: MAT-82717-D8J7
F O R E N S I C S Church Insurance Company File No: 36629
Photograph 13.
Typical gaps between roof decking boards
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Photograph 14.
Remnants of ceiling lath.
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E N 1 STA Envista Matter No:MAT-82717-D8J7
FORENSICS Church Insurance Company File No: 36629
Photograph 15.
Remnants of ceiling plaster.
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Photograph 16.
Typical roof decking board.
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EN 1 STA Envisto Matter No: MAT-82717-D8J7
F O R E N S I C S Church Insurance Company File No: 36629
Photograph 17.
Ceiling and roof framing members at interface with bell tower.
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Photograph 18.
Deteriorated connection of members depicted in preceding photograph.
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