2._PDS_FOB_Exterior_Restoration.pdf

Seattle Federal Office Building Exterior Restoration

PROJECT DEVELOPMENT STUDY

GSA Contract #EQ10PCB-2-15-5007

September 2016

Seattle Federal Office Building Exterior Restoration

PROJECT DEVELOPMENT STUDY

TABLE OF CONTENTS

Executive Summary 1

Needs Assessment Report 5

Conservation Strategies 31

Selected Strategy Documentation 65

Appendix

Hennebery Eddy Architects 1

Executive Summary

PROJECT DESCRIPTION

The Seattle Federal Office Building (FOB) occupies a full block of downtown Seattle bound by First

Avenue, Madison St., Marion St., and Western Avenue. It is a 9-story structure designed by acting supervising architect of the U.S. Treasury Department James A. Wetmore and completed in 1933.

It is one of the earliest federal buildings designed in the Art Deco style and was listed on the

National Register of Historic Places in 1979.

The building construction consists of a concrete encased steel structural system clad in red brick masonry with a granite base and buff colored terra cotta at the first floor and parapet. The roof is multi-tiered, cascading down symmetrically from the 9-story central tower fronting 1st Avenue to the two 5-story wings extending west along Madison St. and Marion St. Roofs are flat with tall parapets and clad in built-up and membrane roofing. Windows are double-hung steel, typically paired and stacked in vertical ribbons with decorative aluminum panels between floors.

The building is in need of exterior restoration. The last comprehensive exterior restoration was completed in 1993. Specific areas of work identified in the Scope of Services are 1) exterior facade restoration, 2) roof replacement, and 3) window restoration. The Project Development Study (PDS) is intended to verify the current needs and further develop the scope for this work, as well as develop design-build bridging documents including the project requirements, performance, and

Contractor criteria necessary for the General Services Administration (GSA) to contract for the work using a design-build methodology.

PROJECT GOALS + OBJECTIVES

The primary goals and objectives of the Project Development Study phase of work are to verify the exterior envelope needs of the building, generate feasible conservation treatment strategies, and select a preferred strategy to develop criteria for execution using a design-build methodology. Other objectives include:

• Compliance with the Secretary of the Interior’s Standards and Guidelines for the Treatment of Historic Properties.

• Keeping the building fully occupied and operational during restoration.

• Minimize impacts on tenants and public users.

• Stop material degradation and water intrusion.

• Abatement of hazardous materials.

Implementation through a design-build approach was selected by GSA to minimize risk to the agency and maximize efficient use of time and money by encouraging holistic and innovative delivery solutions.

REPORT ORGANIZATION

2 GSA Seattle FOB Exterior Restoration

This report is organized into the three phases of the Project Development Study - the Needs

Assessment Report, Conservation Strategies, and Selected Conservation Strategy. The phases were consecutive and built on the information developed in the previous phase.

SUMMARY OF PHASES

Needs Assessment Report

The on-site exterior condition assessment, conducted October through December of 2015, found that deterioration is greatest at materials and components located where vulnerable to water intrusion, areas of deferred maintenance, and where past repairs were inappropriate or have subsequently failed. Investigations yielded the following areas of concern:

• The south and west facing elevations are generally in worse condition than the north and east elevations due to greater exposure to weather.

• From the fifth floor up conditions worsen in relation to the terra cotta and the parapets.

• Terra cotta issues include mortar joint deterioration and failure, glaze spalling, previous repair failure, and excessive biogrowth/soiling.

• Brick issues are most serious where inappropriate past repointing efforts resulted in overcutting into brick and terra cotta surfaces, brick face-spalling due to inappropriate repair mortar, and untimely failure of repair mortar due to incorrect repair practices.

• Brick also suffers from erosion of original mortar and excessive biogrowth/soiling.

• Steel window repair is high priority and includes failing glazing compound, light to moderate corrosion of frames and sashes, cracked glass, and paint failure.

• The aluminum spandrel panels are in good condition, but the caulk joint around the perimeter of the panels is nearing the end of its expected life.

• Window washers need to take steps to prevent marking up the building with equipment and shoes and damaging the terra cotta parapets with riggings.

• The ten evaluated roof areas will reach the end of their expected life in the next few years.

• Metal paneling at the back of the parapet walls is trapping moisture against the already damaged brick walls and corroding the paneling and parapet structural interventions from within.

• Hazardous materials are present in the window paint, glazing compound and brick mortar.

Follow-up recommendations included further investigation of the parapet and roof structure, additional mortar analysis, and evaluation of mechanical upgrade needs that could be implemented in tandem with the roof replacement.

Conservation Strategies

Based on the findings and initial conclusions drawn in the Needs Assessment Report, conservation strategies - including baseline approaches and alternative options - were developed and presented with advantages and disadvantages, potential preservation and environmental impacts, and order of magnitude costs.

Basic recommendations included cleaning, repointing of masonry, replacement of sealants, specific material repairs, and replacement of roofing systems. Alternatives included options for the amount of repointing, the type of roof system, the treatment of the backside of the parapet walls, the

Hennebery Eddy Architects 3 treatment of the sky-facing mortar joints, and options for upgrades to the steel windows. These strategies were then vetted by GSA and the project team taking into account preservation best practices, GSA standards, and order of magnitude costs.

Selected Strategy Documentation

The following is a summary of the conservation strategies selected by GSA as the preferred approach for each material or component.

• Terra Cotta - Cleaning, glaze and clay body repairs, selective repointing, and a combination of lead and silicone weather caps at sky-facing mortar joints.

• Brick - Cleaning, replacement of damaged bricks, full repointing (all brick except indicated portions of 9th floor), and uncovering and replacement of the roof-facing wythe of brick at all parapets.

• Granite - Cleaning and selective repointing.

• Aluminum Panels - Cleaning and replacement of perimeter sealants.

• Steel Windows - Repair all existing windows, reuse existing intact glass, windows to remain fixed (replace sealants) except for operable roof access windows, apply sun-control window film to new and salvage glass, and provide new interior shades for all windows.

• Roof - Replace per Option #2/5: Modified Bitumen Membrane, leave wood over-framing on 5-story wing roofs in place.

• Abate hazardous materials in compliance with federal and state requirements.

• Repair exterior steel stair - replace components if necessary.

• Repair all exterior steel doors.

Design-build bridging documents including performance criteria specifications, diagrammatic drawings illustrating the assumed scope of work, and a revised construction cost estimate were developed for these selected strategies.

4 GSA Seattle FOB Exterior Restoration

Needs Assessment Report

Introduction 7

Assessment Methodology

Summary of Findings

Condition Assessment 11

Masonry - Terra Cotta

Masonry - Brick

Masonry - Granite

Aluminum Panels

Steel Windows

Roof

Hazardous Materials

Other Observations

Hennebery Eddy Architects 5

6 GSA Seattle FOB Exterior Restoration

Introduction

The first phase of the Project Development Study consists of on-site investigation of existing conditions and production of a Needs Assessment Report. Key components of the report include assessment findings, applicable design standards and code requirements, and identification of unique situations and risks that may impact implementation of rehabilitation work. This initial assessment is intended to inform the generation of phase two conservation strategies.

ASSESSMENT METHODOLOGY

All condition findings in this report are based on the field survey conducted October 14-15, November 4-5, and December 9-10, 2015. The project team had access to all roofs and the exterior perimeter to perform a visual assessment of the current physical conditions. Boom lifts were used to access the upper floors of the west and parts of the north and south elevations. Masonry specialists with Pioneer Waterproofing provided photographic documentation of the east and west elevations of the central tower by bosun chair. No destructive investigation was performed.

Conditions were photo-documented and recorded digitally using mobile tablet technology.

Recorded condition data has been organized by material in this report. Annotated field notes have been included in the Appendix.

Reference materials included:

• 2014 Bronze Treatment Study

• 2014 Memo -Exterior Window Caulk Samples for Asbestos and PCBs

• 2013 Window Condition Survey and Elevation Diagram

• 2007 Building Preservation Plan

• 2007 Window Study

• 2007 Asbestos Reinspection Survey Report

• 2006 Roofing and Terra Cotta Study

• 2005 Leak Investigation Report

• 2003 Limited Scope Restoration Project

• 2003 Report of Hazardous Materials Survey

• 1984 Historic Structure Report

• GSA Technical Preservation Guidelines

• NPS Preservation Briefs

Hennebery Eddy Architects 7

DESIGN STANDARDS - GENERAL APPLICATION

The following standards are applicable overall to this project:

• Facilities Standards for the Public Buildings Service PBS-P100 - commonly P100 -including 7.13-Historic Structures o P100 - 4.3.7 Alterations in Existing Buildings and Historic Structures - Alteration requires ingenuity and imagination. It is inherently unsuited to rigid sets of rules, since each case is unique. It is recognized that total compliance with standards may not be possible in every case. Where serious difficulties arise, creative solutions that achieve the intent of the standard are encouraged.

o P100 - 4.3.8 Seismic Upgrading - Historic buildings should meet the same life safety objectives as other buildings while preserving historic spaces and features to the greatest extent possible. Any decision made to preserve essential historic features must not result in a lesser seismic performance than that required by “Standards of Seismic Safety for Existing Federally Owned and Leased Buildings “ICSSC Recommended Practice 8 (RP8).

Where deficiencies in the attachment of elements of structures, non-structural components, and equipment pose a life safety risk, they must be prioritized and those elements with the greatest life safety risk strengthened first to meet current standards.

• Secretary of the Interior’s Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings (36 CFR 67)

• 2012 International Existing Building Code (IEBC)

• 29 CFR 1910 - (OSHA compliance for construction, facility operations and maintenance)

• Maintain an accessible public entrance meeting ABAAS Section 404.3

• Section 106 compliance

SUMMARY OF FINDINGS

Conditions

In general, deterioration of exterior materials and components is at locations most vulnerable to water intrusion, areas of deferred maintenance, and where past repairs have failed. Conditions are generally worse on the south and west facing elevations. These two elevations receive the brunt of the weather - be it sun, rain, or wind. Conditions also worsen from the fifth floor up in relation to the terra cotta and the parapets.

Terra cotta and granite issues are largely related to mortar joint deterioration and failure. Terra cotta glaze spalling is a serious condition, but no discernible pattern has been identified. Brick issues are of most concern including a number of repointing campaigns of varying quality and appropriateness and brick face-spalling. At least two different repointing mortars have been identified, as well as a variety of spot pointing materials, most of which are not a good match to the original mortar appearance and some are suspected to be of a much higher strength than the original mortar causing damage to the existing brick.

Steel windows universally exhibit cracking or failing glazing compound and light to moderate corrosion of the bottom horizontal members of the window frames and sashes. The number of cracked glass panes has continued to increase since the last window survey. Repair of the steel

8 GSA Seattle FOB Exterior Restoration windows is a high priority item. Three pairs of glazed steel doors at roof access locations suffer paint failure and light corrosion as well and should be repaired in conjunction with the windows.

In contrast, the aluminum spandrel panels are in good condition. No evidence of corrosion or galvanic action between the steel windows and the panels was observed. The panels are coated in a metallic paint. The coating appears sound, though soiled. The caulk joint around the perimeter of the panels is performing, but nearing the end of its expected life.

Of the 14 roof areas that comprise the Seattle Federal Office Building, ten were evaluated for this assessment report (per the Scope of Work document generated by GSA). The existing roofing at the north and south wings and flanking the tower is believed to date from the 1993 exterior rehabilitation project and will reach the end of its expected life in the next few years. Additionally, flashing and metal paneling at the back of the parapet walls is trapping moisture against the already damaged brick walls and corroding the paneling and parapet structural interventions from within.

This is a high priority issue.

A review of existing reports has indicated that hazardous materials are present in the window paint, glazing compound and brick mortar. Procedures for proper abatement and disposal will be required.

Next Steps

On-site investigation and findings identified the following additional areas of investigation that GSA may wish to pursue in order to better understand the existing conditions and associated risks.

• Consider additional review of the parapet and roof conditions by a structural engineer. Ground Penetrating Radar (GPR) may be useful in identifying the existence and frequency of structural ties within the terra cotta units and could be included in the structural engineer’s scope of work.

• While the mortar analysis completed in 1984 can be used to match the historic mortar composition, it may also be useful to conduct analysis on the primary repointing mortars used in previous repair campaign. Determining the strength and matrix of material of this mortar will help in assessing the risk in leaving it in place verses removing it and repointing.

• Mechanical needs and upgrades should be evaluated as implementation may make sense in tandem with the roof replacement.

The next phase of the Project Development Study is to generate conservation strategies to address the issues documented by the Needs Assessment phase. Based on the findings and initial conclusions, treatment approaches and options will be developed and evaluated against design standards, level of risk, implementation efficiencies, cost and other applicable criteria. Strategies will be presented to GSA for review and determination of the preferred strategies.

Hennebery Eddy Architects 9

10 GSA Seattle FOB Exterior Restoration

Condition Assessment

MASONRY - TERRA COTTA

Glazed architectural terra cotta is utilized at the first floor level, entries, and all parapet. The first floor consists of a belt course and coursed base units. Due to the steepness of the slope west from

1st Avenue, the terra cotta increases in height along Marion and Madison Streets and clads the full height of the first and basement floors of the five story wings on Western Avenue. Pedestrian entries feature decorative surrounds. At the parapet, individual units typically have decoratively molded outward facing surfaces, but smooth sky- and roof-facing surfaces. The central tower is capped entirely in terra cotta.

The terra cotta glaze is buff in color with a matte finish. Original drawings illustrate the use of natural stone which was replaced with terra cotta during construction. Therefore, there is no documentation showing the internal configuration or anchorage of the terra cotta units.

Current Conditions

GLAZE SPALLING. Surface spalling of glaze was observed at the outward and roof facing surfaces of the west elevation upper level parapets as well as various seemingly random locations at the wing parapets. The full spectrum of the glaze spalling process is in progress ranging from imminent loss of historic glazing to spalling of modern coatings from previous glaze repairs. Glaze spalling is typically a result of water trapped within the body of the unit that is stopped by the glaze until it builds up enough pressure to “pop off” sections of glaze. The presence of glaze spalling is a key indicator that water infiltration at the parapet is ongoing.

PARAPET EDGE CHIPPING. Currently there are no tie-offs for window washers to use to drop the exterior elevations. The method observed during our site visit involves tying ropes around the parapet crenellations with additional ropes around the crenellations on the opposite parapet. The material impact of this practice is evident with chips and wearing of the unit edges where the ropes run over the parapet. The edges of terra cotta units are the most vulnerable.

SURFACE PITTING. Holes or pits in the finished surface of individual terra cotta units were observed at random locations. These pits tend to be 1/2” or less in diameter and depth and concentrated on particular units. There is no obvious pattern affecting other adjacent or similarly located units. There is also no collateral damage such as glaze chipping around the pits. This suggests a material defect in select units present since manufacturing - units that probably should have been rejected during construction.

BIOLOGICAL GROWTH + SOILING. All terra cotta is generally dirty. Sky-facing units have a fair amount of bird excrement build-up and several seagull nests were found in protected roof corners.

Moss is prevalent in deteriorated mortar joints and open cracks. Larger pockets have become hosts to full size ferns. Surface soiling occurs under profiled banding at the watertable course of the base.

Hennebery Eddy Architects 11

MORTAR JOINTS - GENERAL. A majority of the mortar joints have been raked out and, in most cases, repointed. The vertical joints on the backside of the central tower parapet do not appear to have been completed, only raked out. Repointing using inappropriate tools is evidenced by over-cutting of joints into the terra cotta units. Where brick was repointed at a 90-degree angle from terra cotta units, the faces of the units were cut into, leaving circular blade marks every three to four inches. Joints are in better condition at the terra cotta base level, but localized joint failure is still a problem, particularly at horizontal joints where the terra cotta meets the other masonry materials -brick and granite.

MORTAR JOINTS - SKY-FACING. Sky-facing joints at the parapets and stepped central tower have been raked out and, in most cases, repointed. The joints on the back of the central tower parapet have only been raked out. Sky-facing parapet joints have been covered with Dow Corning 123

Silicone Seal, an extruded silicone product cut to length and adhered to either side of the mortar joint with silicone sealant. The existing seals have been damaged by birds pecking holes in the non-adhered center of the strips. The installation also cut the seal strips at the edge of the units -compromising the edges - rather than extending the seals over the edges slightly to complete the seal. Joints at window sills within the terra cotta base and at the base top appear in better condition, but not used consistently.

PREVIOUS REPAIRS. A rolled or sprayed-on coating was applied to many of the sky- and roof-facing surfaces of parapet units, as well as some outward facing surfaces at the parapet, base, and entries. This coating is a relatively close match to the original buff color and is performing well in most applications other than the previously identified areas suffering from ongoing glaze spalling.

Crack patches appear to be generally performing well. Some failures were observed, particularly at cracks in the central tower stepped units. Holes have also been left in the central tower terra cotta after removal of mechanical system anchors.

Preliminary Conclusions

• All conditions are repairable; no units were observed that require replacement.

• Water infiltration through the parapet is a high priority issue. Deficiencies including sky-facing joint treatments, mortar joint conditions, material spalls, and roofing are key contributors.

• Explore through-wall flashing at appropriate locations as an option to resolve multiple parapet issues.

• General cleaning and repointing is needed.

Unique Situations/Risks

The following list includes unique issues or risks to be aware of:

• The internal structural condition of the terra cotta is unknown. The condition of ties at the parapet, particularly where water intrusion is obvious, is unknown and may be of concern.

• The adequacy of current parapet bracing methods should be reviewed by a structural engineer.

• Scaffolding will be required to do facade repair work unless anchorage is installed at the roof to support swing stages.

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• If a through-wall flashing option is pursued, a practical strategy for removal and reinstallation of terra cotta coping pieces will need to be evaluated.

• The entries will require protective covering. Sidewalks may also require covering.

• Street and sidewalk closures may be required. Street lighting and electrical/bus lines may be affected.

Design Standards

• GSA Historic Preservation Technical Procedures o Repairing Spalled Terra Cotta o Repointing Terra Cotta o Sealing Terra Cotta o Patching Small Holes, Minor Chips and Spalls in Terra Cotta o Removing Bird Excrement from Masonry Buildings

• NPS Preservation Briefs o #7 The Preservation of Historic Glazed Architectural Terra Cotta o #1 Cleaning and Water-Repellent Treatments for Historic Masonry Buildings o #2 Repointing Mortar Joints in Historic Masonry Buildings o #6 Dangers of Abrasive Cleaning to Historic Buildings

Hennebery Eddy Architects 13

MASONRY - BRICK

The predominant building cladding is brick, in a range of shades from red to orange with a wire-cut finish. Nominal 4 x 8-1/4 x 2-1/4 bricks are laid in a common bond pattern with concave joints.

Current Conditions

FACE SPALLING. In areas experiencing a higher level of moisture saturation for longer periods of time, the finish face of individual bricks is spalling exposing the softer internal clay. These areas tend to be near terra cotta at the parapets extending down through the upper floors and at narrower vertical bands with corners and more exposed surfaces. Larger expanses of brick are less affected.

Face spalling is caused by moisture being trapped within the body of the brick and building up pressure until the fired face pops off. Mortar that is too hard and does not allow the passage of water can contribute to this issue. Face spalling appears to be primarily occurring in the lightest colored orange bricks. This may indicate a difference in material composition and strength of bricks from this color batch.

BIOLOGICAL GROWTH + SOILING. All masonry is generally dirty. Moss is prevalent in deteriorated mortar joints, north facing elevations and interior shaded corners. The pattern of moss growth is an indicator of areas that experience higher moisture levels. Larger pockets have become hosts to full size ferns.

PARGE COATING. At the upper roof levels flanking the central tower, brick has been protected by a cementitious parge extending from the bottom of the terra cotta cap down to the roof flashing. This coating exhibits extensive surface crazing, heavy biological growth, and adhesion failure near the roof flashing and at corners resulting in spalling and exposure of the brick. Previous reports indicate that this parge coating was added to these areas because the condition of the brick is so severe.

There is also mention of previous sandblasting at these areas.

MORTAR JOINTS - GENERAL. A majority of the mortar joints have been raked out and, in most cases, repointed. At least two different repointing campaigns are evident - one with an inappropriate hard grey mortar and the second with a more appropriate softer sandy colored mortar. Repointing using inappropriate tools and techniques is evidenced by the over-cutting of joints into adjacent brick and terra cotta units and the widening of joints up to 1/4” by cutting into the ends of the bricks. Joints were also marginally raked prior to one of the repointing projects. Industry standard is to remove mortar to a depth 2 to 2.5 times the width of the joint, and back to a point of sound material. The existing joint width is approximately 1/2”, corresponding to an appropriate raking depth of about 1-1/4”. However, joints were raked less than 1” in most cases. Combined, these issues have resulted in failure of the mortar joints as evidenced by dislocation of the repointing mortar and an unusual pattern of joint erosion.

PREVIOUS BRICK REPAIRS. Individual brick units have been replaced with two types of infill - a light red, smooth-faced brick not matching in color or finish, and a brick with a 1/2” section of brick epoxied to its end to match the existing brick width. The wire-cut brick provides a better match, but

14 GSA Seattle FOB Exterior Restoration may also provide a point of entry for water depending on the condition of the epoxy filling the gap.

Additionally, light colored replacement units that are cracked vertically through the center are in fact patching compound that has either been applied over the spalled brick or used to infill the loss of a complete brick unit.

Preliminary Conclusions

• Previous repairs were not properly executed, contributing to the present level of deterioration and failure.

• Water infiltration through the parapet into the walls below is a high priority issue.

• Face-spalling of the orange bricks is unique and should be better understood.

• General cleaning and repointing is needed.

• Mortar analysis completed as part of the 1984 Historic Structure Report is useful in understanding the historic mortar composition, however, the repointing mortar should also be analyzed to understand its suitability and associated risks.

The following list includes unique issues to be aware of:

• The appropriateness and performance of past repairs and the desired performance of proposed repairs should be considered in determining the extent of proposed repointing and brick replacement.

• Analysis of face spalling bricks may be useful in understanding and finding appropriate treatments.

• Scaffolding will be required to do facade repair work unless anchorage is installed at the roof to support swing stages.

• The entries will require protective covering. Sidewalks may also require covering.

o General Cleaning of Exterior Brick Masonry o Patching Cracks in Brick Masonry o Removing and Replacing Deteriorated Brick Masonry o Repointing Masonry Using Lime Mortar o Removing Biological Growth from Exterior Masonry o #1 Cleaning and Water-Repellent Treatments for Historic Masonry Buildings

Hennebery Eddy Architects 15

MASONRY - GRANITE

The base of the building is light grey granite rising up to just below the first floor windows with narrow mortar joints. On the west elevation, the two-story portion between the flanking five-story wings is clad entirely in granite with a decorative terra cotta parapet cap that aligns with the adjacent belt courses. Granite features on this portion fronting Western Avenue include coursed blocks, vehicular openings with carved “entrance” and “exit” signage, large archways over the recessed loading dock area and circular columns.

Current Conditions

BIOLOGICAL GROWTH + SOILING. All granite is generally dirty. Light biogrowth is typical on sky-facing surfaces, such as sills and the top of the columns, and where the planters or sidewalk abut the granite base.

MORTAR JOINTS - GENERAL. The mortar joints are for the most part intact. Localized mortar failure exists throughout - some mortar has separated from the stone and others have fallen out. The worst conditions are at horizontal joints where the granite meets the terra cotta. An anomaly was observed on the south elevation under a window in one of the planters. Water was saturating the stones adjacent to a mortar joint - apparently coming from the joint itself. This issue requires further investigation to fully understand.

STAINING. In several areas on the west elevation granite, staining bordering the mortar joints is evident. This may be caused by prior repointing, cleaning, or other treatment.

Preliminary Conclusion

• Some previous repairs were not properly executed.

• General cleaning and localized repointing is needed.

• Testing of potential cleaning solutions or poultices is required to determine if the staining can be removed.

• Consideration should be given to replacing the mortar in the joint between the granite and the terra cotta with a flexible sealant.

• The appropriateness and performance of past repairs and the desired performance of proposed repairs should be considered in determining the extent of proposed repointing and brick replacement.

o General Cleaning of Granite

16 GSA Seattle FOB Exterior Restoration o #1 Cleaning and Water-Repellent Treatments for Historic Masonry Buildings

Hennebery Eddy Architects 17

ALUMINUM PANELS

Decorative aluminum spandrel panels are located between steel windows in vertical ribbons flanked by brick on all facades. There is a standard ribbed and panelized rectangular panel type and there are more decorative thematic panels. All panels are coated in metallic paint and separated from other surrounding materials by a sealant joint.

Current Conditions

GENERAL SOILING. All panels are dirty with greater dirt and build up in panel profiles and decorative moldings. Dark marks commonly occur on smooth surfaces and it is suspected that the marks are from window cleaners’ shoes.

CORROSION. There was no evidence of corrosion observed at survey locations.

SEALANT JOINTS. The perimeter sealant joints separating the aluminum panels from the steel windows and the brick masonry are intact, but near the end of their expected life. They appear dry and less flexible than is desired.

Preliminary Conclusion

• General cleaning is needed.

• Perimeter sealants should be replaced.

• Window washers should wear non-marking soled shoes.

• Testing of the metallic coating has not been done. Testing should be done or care should be taken to not disturb the coating when cleaning and sealing.

o Aluminum: Characteristics, Uses and Problems o General Guidelines for Repairing 3-D Aluminum Features o Classifications of Aluminum Cleaners o Preserving and Restoring the Aluminum Finish of Decorative Architectural Features

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STEEL WINDOWS

The typical window consists of a steel frame and double-hung sash in a two-over-two glazing configuration. These are either single, paired with a horizontal mullion, or in groups of three with transoms. Shapes include rectangular, arched head, or custom. Larger and custom windows have more muntin divisions.

Each window is constructed of galvanized steel with riveted and soldered joints. Operable windows include sash pulleys with galvanized chains and weights, weather guides, a sash lock at the meeting rail, one exterior upper sash pull and two interior lower sash lifts. Glass is typically single-pane clear glass set in glazing compound. Obscure pattern glass is used at restrooms. Wired glass is used at stair locations.

Current Conditions

Windows were documented on the fourth floor (and three pairs on the fifth floor) from the interior, at the ground floors from the exterior, and wherever accessible from the roof and boom lifts.

PAINT FAILURE. Windows are suffering from universal paint failure associated with deterioration over time. Peeling paint coupled with failure of glazing compound exposes the steel to weather, leading to corrosion. Paint failure is particularly concentrated at bottom rails, sills, and steel lintels.

GLAZING COMPOUND FAILURE. Glazing compound is universally dry, cracked, and failing. Loss of seal to the glass or sash, as well as complete loss of the glazing compound in some locations, provides opportunities for water to collect and rest on exposed steel surfaces, resulting in corrosion.

STEEL CORROSION. Findings corroborated GSA findings in the 2013 FOB Follow-up Window

Condition Survey. In general, there is greater corrosion at windows on the south and west facing elevations, and deterioration has slowly continued since the 2013 Survey.

All windows exhibit some level of corrosion, predominantly at the bottom rails of the upper and lower sashes, sills, vertical members in contact with sills, and steel lintels. Corrosion is typically light surface rust that can be easily removed. A few more severe conditions were observed at the following locations:

• Moderate corrosion at the lintel and frame head of the pair of windows under the stair on the west elevation to the south wing roof.

• An aluminum storefront system was installed at the interior side of three paired window openings on the fifth floor of the east elevation as part of a recent renovation. As noted in the 2013 Survey, this alteration appears to have accelerated corrosion at these six windows. More severe corrosion in the form of rust jacking is present at the bottom rails of the upper and lower sashes as well as a higher degree of paint failure. Deterioration of the frames appears to be limited to paint failure with minimal corrosion. Due to the fixed aluminum storefronts, direct access and observation was not possible.

Hennebery Eddy Architects 19

BROKEN GLASS. Broken panes of glass were documented on the fourth floor. Approximately 5% of the panes are broken. In comparison to the cracked pane chart in GSA’s 2013 Survey, we found up to three additional windows per elevation with one or more cracked panes not previously noted.

When extrapolated across all nine floors there is a potential increase of 40 to 120 windows with panes that have cracked in the last two years.

CAULKING. Caulking around the window perimeters observed by Pioneer Waterproofing on the east and west elevations is at the end of its useful life. Caulking is dry, cracked and detaching from the window frames and adjacent materials.

HEAT GAIN/LOSS. Windows are clear, single-glazed, non-thermally broken steel. Though originally double-hung, allowing operability of both the lower and upper sash, all windows (with the exception of those required to access various roof levels) have been sealed shut. Occupants on the south and west facing elevations suffer extreme temperature fluctuations year-round. Increased air infiltration due to failure of sealants and glazing compound is a contributing factor.

INTERIOR WINDOW TREATMENTS. Metal mini-blinds are typical treatments at most fourth floor windows. A majority of these blinds have broken mechanisms, missing pull strings, or are damaged in some other way. Many were no longer securely installed, posing danger to occupants attempting to operate them.

Preliminary Conclusions

• The increase in number of broken glass panes, including windows with no previously documented broken panes, is of serious concern. Addressing window deterioration is a high priority.

• General repairs may include replacing all glazing compound, removing loose paint and corrosion, treating metal with a rust-inhibiting primer, reglazing and painting.

• The three pairs of windows on the fifth floor of the east elevation with severe corrosion require destructive investigation to determine whether they can be repaired by component replacement, sash replacement only, or require full replacement.

• Previous testing of the glazing compound found it contains PCBs, but below the EPA level that requires any special handling. However, paint has not been tested and likely contains lead. See Hazardous Materials section for further information.

• Alternate options to consider include restoring operability, repair in-place vs. in-shop repairs, energy-efficient glazing options, films, and replacement shades.

• Hardware is only of concern at windows that remain operable for access.

The following list includes unique issues or risks to be aware of:

• Lead paint abatement procedures required.

• Replacement windows for the three pairs of windows on the primary east elevation must match the existing in size, configuration, material and profiles.

• The entries will require protective covering. Sidewalks may also require covering.

20 GSA Seattle FOB Exterior Restoration o Stripping and Repainting Exterior Galvanized Metal Windows o Cleaning and Painting Steel Windows o Replacing Broken Glass in Wood and Metal Windows

• NPS Preservation Briefs o #13 The Repair and Thermal Upgrading of Historic Steel Windows o GSA Technical Preservation Guidelines - Upgrading Historic Building Windows

Hennebery Eddy Architects 21

ROOF

Of the fourteen roof areas that comprise the Federal Office Building, ten were evaluated for this assessment report. Two different types of roof systems cover these areas - Granule Surfaced BUR and Granule Surfaced Modified Asphalt BUR - each with differing conditions and estimated life spans as identified and summarized in the chart below.

The roof systems cover approximately 48,000 square feet. The evaluated areas (Roof Areas A through J) are believed to have been installed as part of the 1993 exterior rehabilitation project.

These existing roof systems are very near the end of the predictable performance service life.

Current Conditions

Roof Areas A+B

A single roof membrane is mechanically attached to a wood roof deck constructed on top of the level cast-in-place concrete roof deck. The wood roof deck consists predominantly of a 4x4 post-and-beam style framing system (sloped at approximately ¼” per foot) supporting 4x4 roof joists topped with 1x6 tongue and groove wood sheathing. Attachment of the framing system to the concrete roof deck is undetermined but employs 2x4s to at least stabilize the base of the posts. The exposed framing members appear to be minimally secured in a toe-nailed fashion (reference the construction drawing detail to the right). The wood over-framed structure is in good condition and exhibits no indication of insect or moisture related damage.

An attic space created between the concrete deck and the framing system is believed to have received an insulation upgrade in 1993 consisting of a 6mil visqueen vapor barrier overlaid on the original 1” wood fiber insulation board located on the surface of the concrete roof deck.

Approximately 10” of glass fiber insulation is installed on top of the vapor barrier. The attic space has no active ventilation provisions. The insulation and vapor barrier are in good condition, minor organic growth was noted between the vapor barrier and the wood fiber insulation. Electrical conduits were observed within the attic space, both abandoned and what appeared to be active runs.

An asphalt saturated base sheet is nailed to the wood deck over which one ply of Type IV asphalt saturated felt is fully adhered with hot asphalt. The ply sheet is topped with a hot asphalt fully adhered SBS modified asphalt top ply sheet manufactured with a mineral granule surface. The surface of the roof is aged and shows areas of additional wear and damage where staging for building maintenance activities have been taking place. The membrane is experiencing typical wrinkling and blistering, but no significant detrimental conditions were observed. The roof membrane remains functional and is performing without leakage; however the point where predictions of future performance can be reliably offered has likely been reached.

The roof drainage system appears to be in good working order and is expected to remain functional well into the future as a nearly complete replacement of roof drains and piping appears to have

22 GSA Seattle FOB Exterior Restoration been completed with Wade cast iron drains and piping. Observations made of the drain bodies and interior insulated piping on these roof areas revealed the presence of a typical obstruction within the overflow drain pipes which was confirmed to be a vane-style water flow alarm system manufactured by Potter Electric. Confirmation of the function and monitoring of this alarm system should be performed as part of any scheduled roof system maintenance. Other roof penetrations are limited to a few curbs and vent pipes, all of which are of no immediate concern.

Sheet metal wall flashing is installed extensively around the interior perimeter of the roof areas and consists of precoated galvanized steel S-lock seamed wall panels anchored to the brick masonry parapet wall. The wall panels are weather lapped by a matching lap seamed reglet mounted counter flashing inserted into the mortar joints at the base of the terra cotta wall caps. The counter flashing reglet is sealed into the mortar joint rather than mortared and the sealant is debonded and failing in most locations. The counter flashing has areas of significant corrosion at the reglet leg and at lap seams. The wall panels exhibit areas of corrosion at seams and where contact with the underlying parapet bracing occurs. Condensation and indications of moisture are present on the backside of the sheet metal wall treatments. Mechanical anchors are heavily corroded with several having been completely deteriorated just past the point of penetration into the masonry wall. The parapets are heavily occupied by seagulls and excrement is constantly on most horizontal exterior surfaces. Corrosion resistant metals, as was used for original construction, should be employed for flashing at all exposed areas.

At the time of the inspection, the masonry parapet wall was generally saturated with moisture. The face of the masonry under the counter flashing is characterized by extensive efflorescence and spalling brick faces. Past weatherization efforts are in the form of fluid applied asphaltic damp proofing and water block type coatings which have potentially contributed to the failing brick faces and saturation by limiting drying. The parapet wall has also been fitted with a 4x4 steel ‘L’ angle strap presumably intended to provide seismic bracing. The angle is positioned approximately halfway between the top of the parapet wall and where it meets the concrete deck below the over framed wood roof deck. The steel angle and anchor bolts were found to have surface rust in areas and active bulk water was migrating on the surfaces. Seismic bracing ‘kickers’ are not present from the wall to the concrete roof deck as with Areas G and H, although the parapet wall heights are similar; installation may not have occurred due to some rationale such as building height, wall thickness or funding restrictions. The need for kickers at the parapet walls should be evaluated at these areas.

At areas without seismic bracing and wall panels, reglet mounted counter flashing ties the brick to the roof termination. In most cases the counter flashing allows for the minimum appropriate eight inch high vertical roof termination. At the east end where these roof areas abut the dome shoulder, potentially original copper reglet mounted counter flashing exist with seams soldered watertight. At the penthouses (Roof Areas C and D) newer precoated galvanized steel counter flashing has been provided and has been caulked into the mortar reglet and the seams have been sealed.

Roof Areas C-J

Hennebery Eddy Architects 23

In general, these roof areas are all supported by level cast-in-place concrete roof decks which have just one existing roof assembly consisting of a self-adhering polyethylene-faced bituthene sheet type vapor barrier onto which a ¼” per foot tapered rigid polyisocyanurate insulation system is adhered. The roof membrane is believed to have been adhered to the surface of an adhered ¾” perlite cover board and consists of an asphalt saturated base sheet to which an SBS modified asphalt top ply sheet with a mineral granule surface is fully adhered with cold asphalt based adhesive. The surfaces of the roofs are aged and show areas of additional wear and damage where building maintenance activities have been taking place on the mechanical decks on Roof

Areas G, H, I, and J. The surfaces of roof membranes are in much better condition on Roof Areas E and F and these are very infrequently accessed. Roof Area I is the only roof which was noted to have active leaks.

In general, the membranes on these roof areas are experiencing only minor granule loss, remain functional and performing without leakage; however the point where predictions of future performance can be reliably offered has likely been reached.

The newer roof drainage system appeared to be in good working order and is expected to remain functional well into the future, as a nearly complete replacement of roof drains and piping appear to have been completed with Wade cast iron drains and piping. As with Roof Areas A and B, the interior insulated overflow drain pipes have been fitted with a vane-style water flow alarm system manufactured by Potter Electric with the exception of Roof Areas C and D. It was noted that the overflow alarms were operating in the main roof drain on Roof Areas I and J. Verification and correction of drain ring position or alarm system position should be performed. Confirmation of the function and monitoring of this alarm system should be performed as part of any scheduled roof system maintenance.

The roof drainage and insulation provisions are negatively impacted by a trough that extends from the roof drain to the roof access door on Roof Areas F and G only. The original access door on

Roof Area H has been removed and access is obtained via a window. Roof access to Area E appears to have always been intended to be through a window. At these roof areas the relatively low threshold of the roof access door could not accommodate the increase in elevation that resulted from the addition of the insulation assembly to the concrete roof deck. The trough seems to be the solution to reducing the possibility of water intrusion into the door opening on these roof areas. The base of the door frames exhibit corrosion. Consideration should be given to replacing or modifying the doors with a raised threshold eliminating the need for the troughs.

Original drawings indicate a waterproofing membrane with a terra cotta tile deck surface at Roof

Areas E, F,G,H. Evidence of the tile system was not observed, however historical photographs may reveal the tile system in service. Consideration should be given to restoring these terrace deck surfaces, though more recent mechanical equipment additions and seismic bracing may make this approach less practical.

Roof penetrations are fairly dense and generally do not permit an appropriate roof membrane termination height. Over-roof ductwork and related flashings are sealant dependent. Ductwork and

24 GSA Seattle FOB Exterior Restoration chiller piping are low to the surface of the roof and render parts of the roof unserviceable. Several mechanical curb clearances from other roof terminations are insufficient and problematic. Several mechanical units are mounted on spring isolators which are no longer supporting the units. Use of high maintenance pitch pocket style flashing at structural type penetrations is pervasive. Significant mechanical upgrades should be considered in tandem with roof replacement as shut down and removal will be required for effective long term leak free integration into the roofing system.

Sheet metal wall flashing has been installed extensively around the interior perimeter of the roof areas and consists of precoated galvanized steel S-lock seamed wall panels anchored to the brick masonry parapet wall. The wall panels are weather lapped by a matching lap seamed reglet mounted counter flashing inserted into the mortar joints at the base of the terra cotta wall caps. The general condition of the wall flashing is similar to that of Roof Areas A and B. Metal wall panels were utilized to weatherize all brick surfaces exposed on the interior faces of the parapet walls, as well as to cover and protect recent seismic bracing.

The parapet walls have also been fitted with a 4x4 steel ‘L’ angle strap presumably intended to provide seismic bracing. The angle is positioned approximately halfway between the top of the parapet wall and where it meets the concrete roof deck. Only Roof Areas G, H, I and J were noted to be fitted with additional bracing which extends from the steel angle outward and downward to the roof deck. The round pipe braces have been unconventionally flashed with EPDM graduated pipe boots which have been incorporated into the SBS penetration flashing system; however, past performance appears to have been adequate. Seismic bracing ‘kickers’ are not present on Roof

Areas E and F from the wall to the concrete roof deck as with other roof areas in this group, though the parapet wall heights are similar; installation may not have occurred according to some rationale such as building height, wall thickness or funding restrictions.