Appendix_A_Tubbs_Cordage_Conditions_Assessment_FINAL.pdf

Architecture Planning Conservation

CONDITION ASSESSMENT

Tubb's Cordage Building

PMIS 254257

Hyde Street Pier, San Francisco Maritime National Historical Park | January 8, 2021

REVISED FEBRUARY 5, 2021

CLIENT:

Robert Peccia & Associates, Inc.

P.O. Box 5100 Kalispell, MT 59903

Ryan E. Mitchell, PE, PLS Senior Project Manager

ARCHITECT:

Architectural Resources Group, Inc.

Pier 9, The Embarcadero, Suite 107 San Francisco, CA 94111

David P. Wessel, AIC, FAPT Principal-in-charge

Jennifer Pont, AIC Architectural Conservator, Project Manager

STRUCTURAL ENGINEER:

Tuan & Robinson Structural Engineers, Inc.

444 Spear Street, Suite 101 San Francisco, CA 941105

Eugene Tuan President

WOOD TECHNOLOGIST:

Flynn & Associates, Inc.

P.O. Box 805 El Cerrito, CA 94530

Kevin Flynn Forensic Wood Scientist

ARG Project No. 180610.01

Cover Photo by Steven Turner, NPS. Tubb's Cordage Building Historic Structures Report 2018.

Table of Contents

1. Introduction

Executive Summary

2. Methodology

On-Site Assessment

Cost Estimate

Guidelines

3. Brief History and Building Description

4. Existing Conditions

Exterior Wood Siding

Windows

Doors

Roof

Crawl Space

Interior

Attic

5. Seismic/Structural Assessment

Table of Contents continued

6. Repair Recommendations

Termite Infestation

Exterior Wood Siding

Windows

Doors

Roof

Crawl Space

Interior

Attic

Appendices

A. Survey of Existing Conditions

B. Report by Flynn and Associates

C. Report by Tuan and Robinson

1Architectural Resources Group | Tubbs Cordage Building

Site Plan, with the San Francisco Maritime National

Historical Park outlined in green and the building location circled in red.

INTRODUCTION

Architectural Resources Group, Inc. (ARG) was retained by Robert Peccia & Associates (RPA) on behalf of the National Park Service (NPS) Pacific West Region for the Tubb’s Cordage Building Pre-Design Condition Assessment at Hyde Street Pier in the San Francisco Maritime National Historical Park in San Francisco, California. As part of this assessment, a structural engineer and a forensic wood technologist were part of the team from ARG that assessed the building.

Executive Summary The Tubb's Cordage Building at Hyde Street Pier is in fair to poor condition. There is termite damage throughout the building, and deterioration associated with wood rot, deferred maintenance and general weathering.

The purpose of this assessment was to provide a critical examination of the building interior and exterior including walls, windows, doors, and decorative elements. In this report, the condition of each material is described. Based on the inspection and found conditions, a range of repair and treatment actions were developed. These are organized by elevation to aid in the planning of treatment and maintenance for the structure.

METHODOLOGY

On-Site Assessment The building was inspected and surveyed on October 28, 2020. In attendance were ARG Architectural Conservators David Wessel and Jennifer Pont, as well as Eugene Tuan of Tuan & Robinson Structural Engineers, and Kevin Flynn of Flynn & Associates. Access to the building was provided by Steven Turner of NPS, and included the interior, attic, and crawl spaces of the building in addition to the visible building exterior. The attic was accessed via stepladder, and the scrawl space as accessed via a vent and a section where the plywood skirting was removed for this purpose. Due to construction techniques, properties of some construction materials used in façade construction, and limitations in detecting concealed façade conditions based on visual observation, some conditions may have remained undetected during the inspection. Wood components were evaluated visually, by sounding, and by probing.

Based on this inspection, a range of repair and treatment actions were developed, calling out high, medium and low priority repair and maintenance treatments. In this report, descriptions of existing conditions have been organized by material. Repair recommendations are included following the summary of existing conditions.

N

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Prior to a site visit, the following documents were reviewed. Their findings were reviewed and incorporated where consistent with the observations and recommendations of this report:

▪ NRHP Nomination Form from 1979

▪ HSR Report from 2018

▪ HABS drawings from 2019

▪ Wood Destroying Organism Report, containing the Wood Destroying Pests and Organisms Inspection Report by Lingruen Associates from 2017.

Class C Cost Estimate A Class C Cost Estimate was prepared by ARG and ARG-Conservation Services using templates and guidelines available from the NPS Denver Service Center. This estimate is based on the conditions and quantities recorded in Appendix A, with additional assumptions and allowances based on the recommendations included in this report as well as experiences on similar past projects. A copy of the estimate can be found in Appendix D.

Guidelines The recommendations contained in this report are based on The Secretary of the Interior’s Standards for the Treatment of Historic Properties (The Standards) with Guidelines for Preserving, Rehabilitating, Restoring, and Reconstructing Historic Buildings, and on the Code of Ethics of the American Institute for the Conservation of Historic and Artistic Works (AIC).

The Standards provide general information for stewards of historic resources to determine appropriate treatments.

They are intentionally broad in scope to apply to a wide range of circumstances, and are designed to enhance the understanding of basic preservation principles. They are neither technical nor prescriptive, but are intended to promote responsible preservation practices that ensure continued protection of historic resources. Further, the Code of Ethics of AIC calls for treatments to be “suitable to the preservation of the aesthetic, conceptual, and physical characteristics of the cultural property.” The Code of Ethics also requires an “informed respect for the cultural property, its unique character and significance, and the people or person who created it.”

While deterioration is inevitable, properly enforced conservation and maintenance measures can help to slow down deterioration and conserve existing materials. Treatments listed in this report respond to goals related to the preservation of materials and elements that are original to the construction of the Tubb's Cordage Building. Original or historic building materials, also known as historic fabric, contribute to the significance of a building because they inform the degree of architectural integrity a building retains. Retaining historic fabric increases the authenticity of the character-defining elements and serves broader preservation goals of advancing knowledge about the history of building design and technology. Repairs need to be both visually appropriate to retain character-defining features, and physically compatible to minimize loss of and damage to historic building materials.

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BRIEF HISTORY AND BUILDING DESCRIPTION1

Built around 1889, as the Tubb's Cordage Company's rope factory office, it is a small single-story building measuring 26 by 22 feet and covering roughly 572 square feet. The building is sided with redwood beveled channel shiplap, and painted mineral red, a common color for industrial buildings of the period. The hipped roof is shingled with cedar shingles, and has a brick chimney at the east elevation. Note that at the interior, the chimney and fireplace or hearth has been removed or walled off and is not visible. Six windows, five double hung two over fours, and one stationary window provide light on all sides of the building. There are two exterior doors; the west door has a window and four triangle panels on the lower portion and the south door has four rectangular panels. Both doors and all five of the double hung windows have decorative trim at the interior and exterior. The two west facing double hung windows have more detail work than the north and east windows.

The building was originally located in San Francisco’s Dogpatch Neighborhood, the office was in almost continuous use.

It was moved to the Hyde Street Pier in 1963 and since then it has mostly served as an office for different state and national park departments.

In the beginning it was left as it was received and used to interpret the history of the Tubb's Cordage Company. In the late 1980s it was repurposed to house the parks education department. That lasted until the 1990s when it was taken over by the San Francisco Maritime National Historical Park, Ships Division who up to present day have been using the building as their office. Over the years as the building was repurposed for different uses the interior space of the office has been changed while the exterior has largely been left intact.

The Tubb's Cordage Building represents one of the few remaining examples of San Francisco’s Victorian commercial and industrial architecture, and is highly significant. The building’s Victorian features include the two over four double hung windows, the scroll work around the windows and doors, and the carved corbels. The commercial history the Tubb's Cordage Building represents is perhaps more significant. The Tubb's Cordage Building is from a bygone era when San Francisco was a maritime city with a thriving port, and an enormous fleet of ships all in need of an endless supply of rope.

The windows and doors are the most distinct features on the buildings exterior. The two doors are framed with pilasters and topped with carved corbels leading to protruding cornices. In addition, the west facing door has a carved lintel while the south facing door has a two pane transom window. The double hung windows are uniform and adorned with molded trim, corbels, and cornices, but of smaller proportions. The west and north windows also have carved lintels while the east side window do not.

Few maintenance records exist for the structure, and most refer to work that occurred prior to 2000. Based on conversations with employees, it appears that for the most part, maintenance has been a low priority and was often only addressed when conditions reached a critical level. The interior has seen some light remodelling, including removal of a 1980s bathroom at the southeast corner, and the addition of interior walls to form an office nestled in the northeast corner of the building. The roof was re-shingled in 2008, and approximately every five years the exterior was repainted.

1 This section of the report is based on the National Register of Historic Places Nomination Form (#79000254) by James Delgado and Gordon Chappell, and from the Historic Structures Report by Steven Turner in 2018

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Wood rot below the plywood skirting on the south elevation.

Wood rot and termite damage below plywood skirting at southwest corner.

Termite kick holes on the south elevation.

EXISTING CONDITIONS

Most of the building is in fair to poor condition. The following conditions have been summarized by material, with locations of these conditions noted on drawings located in Appendix A. These should be utilized to better understand the conditions and repair recommendations at the Tubb's Cordage Building.

Exterior Wood Siding The redwood beveled channel shiplap is currently painted mineral red. It is undergoing accelerated deteriorated due to a drywood termite infestation, and is in poor condition.

It isn't immediately clear if this infestation is active, but it is suspected to be so. See the Recommendations section for more information. Note that some conditions are obscured due to the multiple, thick layers of paint that have been applied to the wood.

The following conditions were observed:

▪ The primary cause of wood deterioration appears to be wood decay fungi. This was observed at the base of the shiplap siding, plywood, as well as at other wood elements including the window sills.

▪ The siding is deteriorated where it intersects with the plywood skirting at the base of the building. This deterioration is a combination of insect damage, moisture damage, and wood rot.

▪ There are termite kick holes visible on the exterior of the south elevation, both in the middle of the wall and at the base below where the plywood sheathing was removed to examine the crawl space. Frass was noted on the ground/pier beneath the perimeter of the structure indicating activity and damage to the walls above.

According to NPS personnel, termites were observed flying from some of the kick holes at the south exterior wall during a heat wave this year.

▪ There are horizontal checks running through several

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Damaged and deteriorated siding at northwest corner. Note previous repairs and open checks on the right.

Previously repaired wood check on east elevation.

Damage from gnawing and scratching at north elevation plywood skirting.

boards. Some of these have been previously repaired but have since failed.

▪ There is damage on the plywood siding at the north elevation from animals gnawing and scratching.

▪ There is a thick layer of over-paint on the siding and exterior wood elements at the exterior. This is due to the many layers of paint applied as part of the general maintenance of the building, with little or no paint removal prior to repainting. The overall thickness of these many layers hides the details of the structure and decreases the performance of the siding and trim.

▪ There is bubbling and peeling paint on all elevations, but the most bubbles are found on the east elevation.

▪ There are small amounts of iron deterioration due to rusting nails and other fasteners.

▪ Earlier reports mention damage by powder post beetles, which was not observed during this assessment.

This damage may have been inaccessible during this assessment, or possibly misidentified, as the exit holes of powder post beetles can appear similar to termite kick holes, which were observed.

▪ There are hooks installed in the eaves at regular intervals on all sides of the building. These may be part of a hanging system for holiday lights.

▪ There was an open vent on the north elevation through which raccoons may be entering the crawl space below the structure.

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Hooks installed at regular intervals at eaves.

Damaged siding and corner at northwest corner. Note the open vent.

Area of previous repairs and overpainting at the west elevation.

Overpaint and previous repairs at west elevation.

Bubbling paint at east elevation.

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Deterioration at lower rail, visible even below paint.

1980s window deterioration, from the interior.

Failed glazing putty and sill deterioration.

Windows Most of the windows are wood double-hung two-over-four windows set in ornate protruding window surrounds.

While the wood trim is in fair condition, with certain areas such as sills in poor condition, the window sashes are in very poor condition. There is one single pane window on the east elevation which was added in the 1980s, when this closet area was converted to a rest room. Note that this conversion was short-lived and was removed in the 1990s, but the window has remained. This window is also in poor condition.

The following conditions were observed:

▪ Heavy wood deterioration and rot, mostly at the lower elements including stiles, rails, and sills.

▪ Checking and moisture damage on the bottom rails of the lower sections of both the upper and lower sashes and parting beads.

▪ Cracked and failing glazing putty.

▪ Heavy overpainting in the sash channels and window surrounds, resulting in a loss of detail.

▪ The single-pane window on the east elevation was added in the 1980s as part of converting the building to offices, when this closet area was converted to a rest room. The window shows significant signs of deterioration at the interior due to moisture and termite damage, especially on the lower rail.

▪ The flashing at the exterior above the window surrounds is in good condition.

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Heavy over paint at window surround. Note checks and deterioration at lower rail of sash and parting bead.

Cap and flashing above window surrounds in good condition.

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Heavily deteriorated west door. Note deterioration at the right corner of the threshold.

Cracking on the left side of the south door frame.

Missing element indicated with a red arrow. Cracked glass indicated with a blue arrow.

Doors The door on the south elevation serves as the main entry for the office located in the building, with the west door roped off and inoperable due to its condition. According to the NRHP nomination form, the west door is not original and was added during a restoration in order to allow the public to see inside the building. While the NRHP nomination form states that this same style door was found at the south elevation, this is not currently the case. The south door is a period-appropriate door that does not have glass. It is unclear if this is an original door or an appropriate replacement door.

The west door and threshold are in very poor condition, with heavy deterioration and material loss both in the door and at the threshold. The south door is in fair condition, with most of the deterioration found in the door frame and threshold, which are in poor condition.

The following conditions were noted:

▪ The west door is very heavily deteriorated due to rot and termite damage. This is most visible from the interior, but is discernible from the exterior as well. The deterioration continues into the base of the door surround and threshold.

▪ There are cracks in the frame around the south door, and deterioration at the threshold.

▪ There is a small crack in the upper right corner of the left transom lite at the south door.

▪ There is a missing piece of decorative moulding on the south elevation at the right side of the bracket.

▪ There is leftover hardware from previous doors and screen doors, including additional latch plates and skid plates, and ghosting from hinges.

▪ The wood details of the door surrounds are heavily over painted, resulting in a loss of detail and visible drips.

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Old and unused hardware at south door.

Ghosting from old hardware at south door.

Heavy over paint and drips at detail above west door.

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Roof at east elevation.

East face of chimney. Cracking indicated with a blue arrow.

Open joints at brick indicated with a green arrow Note the flashing at the shingles.

Roof Records referenced in the HSR indicate that the roof was replaced in 2008. The roof appears to be in good condition.

There is a chimney on the east elevation which is in poor condition.

The following conditions were observed :

▪ The roof is clad in cedar shingles and appears to be in good, sound condition.2

▪ There are several cracked bricks and open joints, as well as signs of water infiltration at the chimney in the attic. It is unclear if these are due to a roof leak or incompatible repair materials, and if they are active forms of deterioration, or if the sources of these conditions were addressed in the 2008 roof replacement and these conditions were simply not repaired.

2 The 2018 HSR states that the roof is shingled with cedar shakes, which are hand split and thicker than shingles, which are a relatively thin, sawn product.

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Exposed crawl space. Note wood deterioration and signs of raccoon infestation circled in red.

Termite galleries at crawl space. Photo courtesy of Flynn and Associates.

Crawl Space The elements in the crawl space are in fair to poor condition.

The following conditions were noted:

▪ There is a suspected raccoon infestation, and signs including excrement and trash were noted in the space.

▪ When the plywood siding on the south elevation was removed, this exposed insect and rot damage to the base of the structure.

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Termite damage at quarter round moulding at floorboards.

Water staining at ceiling, below chimney penetration in the roof. Photo courtesy of 2018 HABS report.

Interior The interior walls and ceiling are composed of sawn tongue and groove paneling. Trim at the lower section of the walls is painted in a darker color to create the look of wainscotting.

Added walls at the northeast corner appeared to be clad in drywall in sound condition. Overall the interior is in fair to poor condition, however the paneling may be hiding additional poor conditions below thick layers of paint and in the walls.

The following conditions were observed

▪ Termite damage at the quarter round moulding at the floor.

▪ Water damage at the ceiling below the chimney penetration in the roof.

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Attic The attic framing appears to be in poor condition, with signs of water damage and a dry termite infestation. It is unclear if the roofing material has been compromised as well.

▪ There are large piles of frass from termites infesting the roofing materials and supports. These should be cleaned and monitored to determine if the infestation is still active.

▪ The attic walls and ceiling at the chimney show signs of water infiltration. Plastic was placed in areas in the attic space where leaks had been previously detected.

It is unclear if this was addressed when the roof was replaced twelve years ago, or if it is still an active leak, however wood deterioration was not readily apparent and appeared minor.

▪ Some changes to the structure appear to have occurred during one of the reported moves of the building. The main roof joists visible in the attic varied in dimension, with a mix of alternating 2x4’s and 2x6’s.

▪ Each of the main roof joists have been sawn, all at the same location. The cut joists were braced with a vertical element and sistered together during reconstruction.

This alteration may have occurred during one of he reported moves during the building's life.

▪ The skip sheathing above the joist cut line is not consistent with the skip sheathing below the cut line.

Piles of termite frass in the attic.

Signs of water damage at chimney. Note plastic that was placed to catch the incoming water.

Difference in skip sheathing. Note the sistering member at the joist.

Cut and sistered joist. Cut location outlined in red.

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SEISMIC/STRUCTURAL ASSESSMENT

Based on our review of existing documents, conditions observed during our site visit, the structural engineer identified the following assumed structural/seismic deficiencies.

▪ The existing perimeter wood framed shear walls at the East and West elevations may not be adequate to resist current building code design lateral seismic forces. The North and South wall elevations only have a single door/ window opening in their respective wall elevations and are stronger, but also may not be adequate to resist current building code design lateral seismic forces.

▪ The roof diaphragm may not be adequate to resist current building code design lateral seismic forces. Although there appears to be existing plywood roof sheathing on the existing roof sheathing, it was not determined during our site visit if the existing plywood roof sheathing was adequately nailed to the roof framing to resist seismic forces.

▪ The perimeter walls and first floor diaphragm are not connected to the Hyde Street Pier structure to resist current building code design lateral seismic forces.

▪ There is not a positive connection between the roof diaphragm and the top of the perimeter wood framed walls to transfer in-plane and out-of-plane current building code design lateral seismic forces.

▪ The unreinforced brick chimney may not be adequately anchored and braced to the roof diaphragm to resist current building code design lateral seismic forces.

▪ There is not a positive connection between the first floor beams and the precast concrete piers in the crawl space.

Seismic/Structural Recommendations Conceptual seismic strengthening recommendations include the following to bring the building in general compliance to resist current building code design lateral seismic forces.

▪ Strengthen the existing perimeter wood framed walls with plywood wall sheathing.

▪ Strengthen the existing roof diaphragm with roof sheathing properly nailed to the existing roof framing.

▪ Provide a positive connection between the perimeter wood famed walls and first floor diaphragm and the Hyde Street Pier structure.

▪ Provide a positive connection between the roof diaphragm and the top of the perimeter wood framed walls.

▪ Provide positive anchorage between the unreinforced brick chimney and the roof diaphragm and brace the top of the chimney above the roof to the roof diaphragm.

▪ Provide positive connections between the first floor beams and the precast concrete piers.

Note that analysis of the Hyde Street Pier structure to support or provide lateral resistance for the Tubb's Cordage Office building structure was beyond the scope of this structural/seismic assessment.

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RECOMMENDATIONS

The conditions listed in this report should be addressed and repaired to prevent further deterioration of the building, increase its service life, and enhance its existing service. This will include both repair of existing elements and replacement of heavily deteriorated ones, as well as installation of new flashing systems to extend the service life of the repairs and the structure.

The following recommendations are listed by material and correspond to the existing conditions of the previous section.

Termite Infestation Prior to the following recommendations, areas of the structure such as the attic should be cleared of signs of termite frass. The cleaned areas should be monitored for additional frass, which would indicate that the infestation is active.

Note that this is the primary method used to determine if an insect infestation is active. While powder post beetles were not observed during the assessment, cleaning of existing termite frass will allow for identification of new powder post beetle damage. If the infestation is determined to be active, the building should be fumigated to prevent further loss and deterioration.

It is understood that the location of the structure on the Hyde Street Pier and over water complicates the fumigation process, however this method is the most sure way to end the current infestation and safeguard the structure against continuing loss and deterioration due to termites.

Due to its location on the pier and over water, fumigation will require adequate protection and insulation systems be installed below the building, such as tarps or other barriers to prevent potential water contamination by the fumigation chemicals. This will require the building to be lifted in its current location, which may require a specialty fumigator or pest control company capable of lifting or moving structures, or by multiple companies such as a fumigator/pest control company and a structure relocation company.

Exterior Wood Siding

▪ Following fumigation treatment, the degree of deterioration in the siding and other elements should be fully assessed, as not all damaged elements may require replacement if they have not been structurally compromised.

▪ The build-up of paint on the siding, window, and door surrounds should be removed using a method appropriate for both lead abatement and weathered wood in order to fully assess the degree of deterioration and damage. Following repair and treatment, the building should be cleaned and prepared for refinishing with a coating system compatible with weathered wood. Compatible finishes include oil-modified or alkyd finishes with a low solids content (less than 40%). These are penetrating finishes that include transparent or semi-transparent coatings or stains. Additional information on finishes compatible with weathered wood can be found in Appendix B.

▪ Deteriorated and heavily damaged exterior siding should be replaced in kind to match the existing. Guidelines for the replacement of damaged and heavily deteriorated shiplap siding can be found in Appendix B.

▪ Siding that shows only mild signs of deterioration including isolated insect damage and wood checks should be repaired with a filler or wood epoxy that is compatible with redwood and with the desired refinishing products.

▪ The plywood skirting should be replaced with new preservative-treated plywood and should be installed with an

17Architectural Resources Group | Tubbs Cordage Building integrated waterproofing system including flashing to protect both the plywood and lower cladding from moisture.

▪ Small losses and minor damage such as checks may be repaired with appropriate wood fillers and epoxy systems, however their compatibility with the refinishing system should be confirmed prior to use.

Windows

▪ Heavily deteriorated elements should be removed and replaced in kind. Dutchman repairs may be considered in decorative elements including window frames and sills where deterioration or damage is isolated. The salvage and installation of sound pieces should be considered where possible.

Doors

▪ Heavily deteriorated elements should be removed and replaced in kind. Dutchman repairs may be considered in decorative elements including door surrounds and thresholds where deterioration or damage is isolated. The salvage and installation of sound pieces should be considered where possible.

Roof

▪ While the shingle roof should have many years remaining to its service life, it should be maintained by repairing or replacing loose, missing, or damaged shingles. Guidelines for repair and maintenance of cedar shingle roofing can be found in Appendix B.

Crawl space

▪ The crawl space should be rodent-proofed to prevent infestation. As part of the exterior wood siding treatment, the crawl space should be enclosed with new plywood skirting.

▪ Areas of unpainted or exposed wood should be treated with a liquid borne preservative containing a borate-based preservative and be spray-applied to protect against future insect infestation. The treated areas should also receive a penetrating or film-forming finish to prevent the preservative from leaching and losing its efficacy. Fused borate rods may also be incorporated in larger wood elements, and if utilized, should be checked as part of cyclical maintenance and replaced periodically.

Interior

▪ The interior wood paneling should be monitored for continued water infiltration issues and insect infestation. Areas of heavy damage or loss, such as the quarter molding at the floorboards, may require replacement in kind.

Attic

▪ Following fumigation treatment, the degree of deterioration in structural elements should be fully assessed, as not all damaged elements may require replacement if they have not been structurally compromised. Note that at the time of this investigation, there were no signs of structural damage, but this should be re-assessed following fumigation or pest treatment.

▪ As with the crawl space, areas of unpainted or exposed wood should be treated with a liquid borne preservative containing a borate-based preservative and be spray-applied to protect against future insect infestation. As this area is not exposed like the crawl space, an additional finish may not be necessary. Fused borate rods may also be incorporated in larger wood elements, and if utilized, should be checked as part of cyclical maintenance and replaced periodically.

Architectural Resources Group | Tubbs Cordage Building

Appendix A

Survey of Existing Conditions

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Single row of hooks

Door is heavily compromised by rot and termite damage.

Windows have failing glazing putty

Approximate cut line at attic joists

Two checks on panel underside of protruding door surround

Failed weatherstripping at top of door

Relative to the other windows, this window is in fair condition.

Existing Conditions Survey

West Elevation

LEGEND

CONDITION QUANTITY

Termite Damage 10.41 sqft

Wood Rot 4.80 sqft

Previous Repairs 14.89 sqft

Failing Paint 2.71 sqft

X Abandoned Anchor

Wood Check 7.01 lft

Crack

General Notes:

▪ The row of hooks below the roof line is found on all four elevations. NPS personnel suggested this may be for a holiday light display/installation.

▪ The listed quantities correspond to existing conditions, and do not include concealed conditions including termite damage and wood rot, especially where these conditions are concealed by paint.

Plan:

LEGEND

CONDITION QUANTITY

Termite Damage 10.22 sqft

Wood Rot 1.43 sqft

Previous Repairs 1.61 sqft

Failing Paint 14.15 sqft

X Abandoned Anchor

Wood Check 18.40 lft

Crack

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Existing Conditions Survey

General Notes:

▪ The row of hooks below the roof line is found on all four elevations. NPS personnel suggested this may be for a holiday light display/installation.

▪ The listed quantities correspond to existing conditions, and do not include concealed conditions including termite damage and wood rot, especially where these conditions are concealed by paint.

Single row of hooks

Missing moulding

Check continues onto west side of door surround.

Old screen door latch plate

Ghosting from old screen door hinges

Area with visible termite exit holes. The lower section is consistent with interior termite damage at quarter molding.

Missing area of plywood skirting

Additional cracking at interior of door surround.

Heavy overpainting and paint drips at transom and brackets.

Approximate cut line at attic joists

Section of plywood removed to inspect crawl space and floor joists

Flaking paint on flashing on top of projecting door surround

Plan:

South Elevation

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Single row of hooks

Area of previous water infiltration in attic

Window added during 1980s alterations, and shows heavy deterioration at interior of sash.

X

X X X X

Approximate cut line at attic joists

Mounted electrical box

Mounted light

Open joint at base of chimney at flashing

Plate and bolts that appear to have been added to repair a dropped rail.

Existing Conditions Survey

East Elevation

LEGEND

CONDITION QUANTITY

Termite Damage

Wood Rot 4.12 sqft

Previous Repairs 4.51 sqft

Failing Paint 31.58 sqft

X Abandoned Anchor 5

Wood Check 27.24 lft

Crack 5.28 lft

General Notes:

▪ The row of hooks below the roof line is found on all four elevations. NPS personnel suggested this may be for a holiday light display/installation.

▪ The listed quantities correspond to existing conditions, and do not include concealed conditions including termite damage and wood rot, especially where these conditions are concealed by paint.

Plan:

LEGEND

CONDITION QUANTITY

Termite Damage

Wood Rot 0.89 sqft

Previous Repairs .29 sqft

Failing Paint 1.59 sqft

X Abandoned Anchor 4

Wood Check 3.36 lft

Crack

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Existing Conditions Survey

General Notes:

▪ The row of hooks below the roof line is found on all four elevations. NPS personnel suggested this may be for a holiday light display/installation.

▪ The listed quantities correspond to existing conditions, and do not include concealed conditions including termite damage and wood rot, especially where these conditions are concealed by paint.

Plan:

North Elevation

N

Single row of hooks

XX

X X

Vent was open during survey

Displaced plywood skirtingPlywood skirting has been chewed away, leaving a gap between the pier deck and the base of the structure.

Approximate cut line at attic joists

Appendix B

Report by Flynn & Associates

Flynn & Assoc., Inc.

Forensic Wood Science

P.O. Box 805 El Cerrito, CA 94530

510/758-4686

The Tubbs Cordage Office Building:

An Evaluation of the General Condition of Wood Elements in the National Park Service Building at Hyde St. Pier, San Francisco, CA

Kevin A. Flynn

November 13, 2020

For

Mr. David P. Wessel, Principal Architectural Resources Group

Pier 9, The Embarcadero, Suite 107 San Francisco, CA 94111

Tubbs Cordage rpt01b photo.doc 11/13/2020

Page 2 November 13, 2020

Introduction: During evaluations for the proposed renovation of the Tubbs Cordage Office

Building on the Hyde Street Pier, significant degradation was noted. Two reports, one by

Bruce Badzik, IPM with GGNRA (January 2020, which contained a 2017 Lingruen

Associates Pest Control report) and another by Steven Turner were reviewed to get a history of the building. An updated survey of the office building was desired and this office was contacted regarding the general concerns and the desire to obtain this evaluation. Drawings of the structure and the noted reports were provided for review prior to the site investigation. A site visit was set for October 28, 2020. On this date Steven Turner, with the National Park

Service, met with the team for the investigation. The group included David P. Wessel, AIC, FAPT; Jennifer Pont, AIC PA; Eugene Tuan, SE; and Kevin Flynn, Wood Scientist.

Procedures: The building was examined from both the exterior and the interior. The visible elements on both faces of the exterior wall, and framing or other components beneath the building and visible in the roof structure were examined. The attic was entered using a step ladder and the subarea was partially accessible through the removal of a section of the plywood skirting around the base. The evaluation of the noted wood components was made visually, by probing, by sounding and by the pick test.

Observations and Discussion: The wood components in the building suffered various amounts of damage or degradation from a variety of sources. The primary cause of the deterioration was wood decay fungi, but drywood termite galleries and a roof leak, adjacent to the chimney were also noted. Splitting, animal damage (gnawing and scratching) and mechanical changes were also minor factors. At least one of the mechanical issues appeared to have occurred during a period when the building was moved.

Damage by powder post beetles to material in the subarea was noted in the September 2017

Lingruen Pest report, and it was mentioned in both the January 15, 2020 report by Badzik and the Turner report. It is not known if actual insects were observed or if they were identified by the galleries and exit holes in the structure. Powder post beetle galleries are typically filled with a fine powdery frass and drywood termite galleries are often open or have a more coarse, football shaped frass. No damage that could definitively be identified as having been caused by powderpost beetles was discovered during the most recent evaluation. The galleries observed were typically open or had drywood termite frass within. The degradation noted in

Page 3 November 13, 2020 the reports may have been inaccessible or, possibly, misidentified, since powder post beetle exit holes can appear similar to termite kick holes. Wood members visible in the subarea generally looked sound (Photograph 1, 88) although damage was observed in some of the framing, at the base of the walls, and blocking (Photograph 2 & 3, 95 & 96).

Interior Walls & Ceiling: The interior walls and ceiling were clad with sawn tongue and groove paneling. Trim around the lower portion, with different paint colors above and below, was used to create the look of wainscoting. Added partitions, for the small office, appeared to be clad with drywall and were not fully evaluated. This material appeared to be in a sound condition.

Roof & Attic: Numerous piles of drywood termite frass were observed in the attic

(Photograph 4, 59). This material is ejected from the termite galleries by active termite colonies, though small amounts can fall from unsealed holes without current activity. No galleries were detected in the framing or skip sheathing directly above the piles of frass and it appeared the infestation may have been concentrated in the plywood sheathing above.

The main roof rafters in the attic were of two dimensions, with a mix of 2x4’s and 2x6’s, generally alternating. Each member had been cut, each at the same location in the roof

(Photograph 5, 64). The type of skip sheathing below the cut in the rafters was consistent on each exposure, and sheathing used above the cut was different, but was also consistent

(Photograph 6, 38). The lower rafter sections were braced with a vertical element. The upper and lower rafter portions were sistered together when the building was reconstructed. It was speculated that the rafters had been cut during one of the buildings reported moves.

The weatherproofing at the chimney penetration was compromised at some point and water intrusion was apparent. Plastic was placed in the area where leaks were evident. Wood degradation due to this leak was not readily apparent and appeared minor. Water marks on the ceiling below memorialized the moisture penetration into the building.

The roof of the structure was clad with cedar shingles, a relatively thin, sawn product, not hand split shakes, which are much thicker. The roof was reportedly about 12 years old and the exposure on the shingles was reportedly 4 inches. Shingle roofs with this exposure that use a

Page 4 November 13, 2020 quality grade product, are installed correctly, and are properly maintained typically have a service life of 20 to 30 years.

Siding: Siding degradation was noted in numerous locations. The exterior corners of the building, areas adjacent to trim or other joints, especially around doors and windows. The siding at the base of the wall and the adjacent makeshift plywood skirting were especially vulnerable. Termite damage was noted in some of the exterior siding (Photograph 7, 114).

Frass was noted on the pier beneath the perimeter of the structure indicating activity and damage within the walls above.

Paint: The paint on the building was extremely thick. The building was reportedly painted every 5 years for an undisclosed period of time and had original paint beneath that. Lead would almost certainly be in some of those layers. The excess thickness hides the details of the structure and decreases the performance of the siding and trim. A layer this thick will inhibit moisture migration, preventing the wood from drying out if there is water intrusion. This will lead to the noted decay at many of the joints on the building.

Recommendations: The degradation observed in many of the building components will need to be repaired in order to enhance the performance of the building and to increase its service life. This will involve the removal and replacement of many of the wood components. The doors suffered significant decay, with the front door barely intact. The exterior cladding, siding and trim boards suffer extensive wood decay damage at most joints and in the field of some courses. Limited drywood termite damage was also noted in some of the siding.

Windows suffered a similar fate, with major degradation observed in sill, jambs, casing, stiles, rails, and other components.

As a start, cleaning the attic and the subarea, where frass has accumulated, will enable the area to be observed for recurrence. Vacuuming these areas and looking for new material to be ejected is an easy way to get a preliminary determination regarding whether or not the termite colony remains active. Although no powder post beetle damage was identified during this examination, it is still possible that some elements in the subarea were attacked by this wood destroying pest. Powder from their galleries can also accumulate. No live insects were observed and the damage appeared to be historic.

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The siding on the office was a 10 inch channel groove lap siding, as noted by Turner. I recommend replacing the degraded material with new siding. Standard profiles that approximate the pattern can be found in California Redwood Association publication

“Redwood Lumber Patterns No. 17” (Attachment 1, p. 14). Alternatively, if this pattern is not found to be a match, the existing siding could be used as a pattern, but new cutter heads and set up can be costly. Mr. Turner mentioned that redwood may be available from the National

Park Service. It is important to note that the source of the wood may be important because the commercially available wood today differs from the old growth material at the original time of construction.

For the skirting at the base of the building, an integrated waterproofing system that includes an appropriate weather resistant barrier (WRB), flashing and preservative treated plywood is recommended. Preservative treatment of the plywood is recommended for durability in the harsh waterfront exposure conditions. Stainless steel or hot-dipped galvanized fasteners are recommended.

The shingle roofing should have 15 or more years of remaining service life as long as it is maintained. Loose, broken or missing shingles should be replaced or shimmed, following guidelines from the Cedar Shingle and Shake Bureau (CSSB). When the chimney is repaired flashing should be integrated into the existing roofing to obtain a weatherproof joint. When the roof surface is replaced, the condition of the plywood sheathing should be evaluated for drywood termite damage.

For refinishing I recommend that the wood be stripped of finish using an appropriate method that will be compatible with the refinishing system selected. The stripped surface should be cleaned. The use of a bristle brush can aid in the preparation, but wire brushes or other metal based products should be avoided as staining of the surface can result if fragments or shavings remain on the surface. If greater protection is desired, a water repellent preservative that is compatible with the finish system chosen can be applied. Manufacturers directions and precautions should be followed for all products used.

Finishes that have been evaluated for use on weathered wood are discussed in Attachment 2 and, although no commercial products are named in the publication, discussion with suppliers sdturner Highlight No siding grade recommended.

Page 6 November 13, 2020 and manufacturers representatives should aid in choosing an appropriate product. Low solids content latex finishes that contained approximately 10% raw linseed oil and 11% acrylic resin

(oil modified finishes) were shown to perform well on heavily weathered wood.

Flashing, preferably copper, would provide the best long term protection of the exposed wood elements in the office building, but it is not consistent with the original design and construction. Other methods of repair can also help protect the structure but will require some level of maintenance to maintain effectiveness.

Liquid borne preservatives containing borate based preservative solutions (water or glycol based) should be spray applied to the unfinished materials in the building to protect against future attack. This would be especially important beneath the structure and in the attic, where the material is visible and generally more accessible. Once applied the surface should be allowed to dry and then areas that might be exposed to the elements can be covered with a water-repellent preservative, a penetrating finish or a film-forming finish. The finish will protect the surface of the wood and prevent leaching of the preservative. Fused borate rods are recommended for larger wood components. The integrity of the rods should be checked periodically and if they have dissolved, new rods should be placed in the holes. One source for the borate based preservatives is Wood Care Systems (https://ewoodcare.com).

Various fillers and epoxy systems are available, but long term performance and compatibility with the wood may be difficult to achieve. The dimensional changes between the wood and epoxiy often occur at different rates, eventually leading to failure. One set of products that is designed to work together and that has a good reputation is the “Endrot Wood Restoration

Kit” and it is also available through Wood Care Systems. Numerous other products are also available.

DISCLAIMER

The opinions stated in this report are preliminary and based on the data and documents received and collected to this date. I reserve the right to expand upon or to revise the above opinions as more information is made available to me through discovery, research, and/or testing.

https://ewoodcare.com/

Page 7 November 13, 2020

Photograph 1. The wood in the subarea appeared bright and little indication of degradation was observed. (88)

Photograph 2. Framing at the base of the wall and edge of the subarea had drywood termite galleries. (95) k_fly Line

Page 8 November 13, 2020

Photograph 3. A closer view of the termite gallery exit holes noted in the previous image. (96)

Photograph 4. Piles of drywood termite frass in the attic. The amount of material deposited appeared similar to that noted in previous reports. (59)

Rectangle

Page 9 November 13, 2020

Photograph 5. The roof rafters were cut in the same location on each side of the roof. The lower sections were reinforced with vertical bracing. (64)

Photograph 6. The color of the skip shething on the upper portion of the roof was much brighter than that below. New sisters on the ratters are also evident. (38) k_fly Line k_fly Text Box Transition

Line

Page 10 November 13, 2020

Photograph 7. Drywood termite exit holes were observed in some of the siding. The galleries were not packed with powder. (114)

Attachment 1. Siding Patterns

Redwood Lumber Patterns No. 17

3 REDWOOD GRADEMARKS

3 PATTERNS PROFILED IN THIS BOOK

3 SURFACE TEXTURE

3 GRAIN

3 CONVERSION FACTORS

3 FURTHER INFORMATION

4 S4S DRY DIMENSIONS

4 S4S GREEN DIMENSIONS

4 DESCRIPTION OF ABBREVIATIONS

5-9 TABLE OF CONTENTS

Redwood Patterns

10-12 TONGUE AND GROOVE

13 NAILING TONGUE & GROOVE PATTERNS

14-15 SHIPLAP

16 NAILING SHIPLAP PATTERNS

17-19 BEVEL

20 NAILING BEVEL PATTERNS

21 DECKING

22 PLOWED FASCIA

23 FENCING

24 MOULDING

25-26 INDEX

California Redwood Association 405 Enfrente Drive, Suite 200 Novato,…