COMMISSION 
AGENDA MEMORANDUM                        Item No.          6a 
ACTION ITEM                            Date of Meeting      January 24, 2017 
DATE:     January 17, 2017 
TO:        Ted Fick, Chief Executive Officer 
FROM:    Wayne Grotheer, Director, Aviation Project Management Group 
Stuart Mathews, Director, Aviation Maintenance 
Mike Tasker, Senior Manager, Aviation Facilities and Infrastructure 
SUBJECT:  Concourse B and Concourse C Roof Projects (CIPs #C800770 and C800702) 
Amount of this request:               $6,026,000 
Total estimated cost:                 $13,183,000 
ACTION REQUESTED 
Request Commission authorization for the Chief Executive Officer to (1) authorize construction
of the Concourse B Roof Replacement Project at Seattle-Tacoma International Airport  in the
amount of $6,026,000; (2) advertise and execute a single contract to construct the Concourse B 
and Concourse C Roof Replacements at the Airport. 
EXECUTIVE SUMMARY 
This project will overlay the current roofing systems on Concourses B and C at the Airport. The
portions of the Concourse B and C roof being overlaid were installed in 1991 and are beyond
their useful life expectancy. Warranties on existing roof system have expired and testing of roof
membranes by Airport maintenance staff indicates the membranes are deteriorating. 
Overlaying the roofs helps to assure a stronger positive customer experience and avoids
potential safety issues and concourse closures that can occur with roof leaks. These are the fifth
and sixth projects in a series of roofing projects that replace roofing systems in a prioritized
sequence. 
The Commission authorized construction of the Concourse C Roof Replacement project in
March 2016. A contract was awarded and the contractor mobilized to the site to begin
construction in July. Initial demolition efforts revealed sufficient differences between the design
and actual existing conditions that a lengthy redesign effort was required. It was determined
that the changes were significant enough to warrant a re-design and re-bidding effort. 
During the initial demolition, it was noted that the insulation and substrate beneath the roofing
membrane were in very good shape and the roof would be an ideal candidate for a roofing

Template revised September 22, 2016.

COMMISSION AGENDA  Action Item No. 6a                                  Page 2 of 7 
Meeting Date: January 24, 2017 
overlay instead of a complete roof system replacement. Proceeding with an overlay allows the
Port to retain the existing roofing, insulation and substrate, saving schedule, duration and cost. 
While the existing condition issues on the Concourse C roof were being worked through,
Concourse B roof was under design and also designated via the design process as a good
candidate for a roof overlay. Since Concourse C roof replacement was deferred until 2017 and
Concourse B was slated for 2017, staff decided, after review with Engineering, CPO,
Maintenance, and the Aviation Project Management Group, that these projects could be
procured as one construction project. This will allow the Port to potentially save costs by
initiating a single procurement and managing a single construction contract. 
JUSTIFICATION 
Replacing airport roofs extends the life of the building, an important Port asset. The Concourse
B and C roofs, similar to other critical systems, must be replaced as they age and deteriorate.
The current roofing systems on Concourse B and C are 25 years old and have reached the end
of their dependable leak-free lifespan. Because the roofs are exposed to the elements and
experience wear and tear, when they fail the risk to the traveling public increases, and the safe
availability  of  the  facility  becomes  impaired.  In  order  to  provide  a  leak-free  terminal
environment and safe experience for those who travel through and work in the facility, the
Concourse B and C roofs have been identified as the next roofs to be replaced. 
The recommended replacement age for this type of roof is between 15-20 years. The
warranties have expired as the roofs are beyond the industry standard life expectancy. While
the existing roofs are leaking, those leaks are considered relatively minor at this time. However,
as leaks occur there is the potential for leaking water to enter the public spaces and place both
tenants and passengers at risk of slips and falls. When leaks occur, the Airport may be required
to secure the portion of the concourse where the leaks are occurring during wet weather
events as a preventive measure. This is contrary to the Port's strategy of anticipating and
meeting the needs of our customers, as this action would take portions of the concourse out of
service during a time of increased usage and gate shortages. 
For Concourse B and Concourse C we are replacing the roof using a roof overlay. A roof overlay
replaces the topmost roofing membrane only. It allows the Port to retain and reuse the roofing
materials underneath the roofing membrane. While the existing roof membrane is breaking
down, it has protected the existing materials beneath it allowing for them to be reused. The
overlay will prevent the demolition and haul away of materials that are in good serviceable
condition. In addition, roofing membrane manufacturers will provide the same warranty the
Port receives on standard roof replacement projects that replace everything. As the alternatives
analysis highlights below, an overlay reduces the cost of replacing both roofs by $1.3 million to

Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. 6a                                  Page 3 of 7 
Meeting Date: January 24, 2017 
$2 million, reduces waste, and provides the same anticipated life and warranty as a full
replacement. 
As a result of the termination for convenience of the Concourse C contractor, materials remain
that cannot be returned to the manufacturer.   Staff will return to Commission  seeking
authorization to re-sell or dispose of the material with a company that will re-sell or recycle it 
rather than disposing of it in a landfill. 
Scope of Work 
(1)   Overlay existing roof with new roof 
(2)   Replace/refurbish the Kalwall Skylights 
(3)   Provide access ladders as needed to correct deficiencies 
(4)   Provide fall protection on the mechanical penthouse roofs 
Small Business 
The scopes of work within Concourse B and C related to this roofing project provide a number
of opportunities for small and diverse businesses within the construction and supplier
industries. 
Schedule 
Activity 
Construction start                                2017 Quarter 2 
In-use date                                       2017 Quarter 4 
Cost Breakdown (Concourse B)                         This Request           Total Project 
Design                                                           $0             $1,236,000 
Construction                                             $6,026,000             $6,026,000 
Total                                                         $6,026,000              $7,262,000 
Cost Breakdown (Concourse C)                         This Request           Total Project 
Design                                                           $0               $874,000 
Construction                                                     $0              5,047,000 
Total                                                                  $0              $5,921,000 




Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. 6a                                  Page 4 of 7 
Meeting Date: January 24, 2017 
ALTERNATIVES AND IMPLICATIONS CONSIDERED 
Alternative 1  Delay replacement of the Concourse roofs 
Cost Implications: $25,000-$50,000 potential ongoing annual expense cost per year for major
repairs. 
Pros: 
(1)   No capital funding required. Leaves capital funds available for other projects. 
Cons: 
(1)    Will likely increase maintenance and emergency repair overtime labor costs. 
(2)    As the roofs continue to age, the risk for leaks increases. The risk of significant or
catastrophic failure increases over time with the further breakdown of roof system
materials. 
(3)    Future roof leaks would damage the existing substrate and require a full replacement
in lieu of an overlay. 
(4)    Increases the risk of damage to the interior of the facility due to water infiltration. 
(5)    Damage to the interior of the facility and resulting repair work would negatively
impact customer service. 
(6)    Safety could be compromised due to slip hazards to traveling public and employees
caused by water infiltration to interior walking surfaces. 
This is not the recommended alternative. 
Alternative 2  Full Replacement of Concourse B and Concourse C Roofs 
Cost Implications: $14.5 - $15.2 million 
Pros: 
(1)   The roofing materials, insulation, and substrate will be replaced with new. 
Cons: 
(1)    While  the  roof  membrane  is  wearing  out,  the  underlying  roofing  material  and
substrate (insulation, cover-board, etc.) is in good serviceable condition. 
(2)    Sends 110,000 cubic feet of insulation that is in good condition to the landfill. 
(3)    Cost for a full replacement is more than the cost of an overlay. 
(4)    Concourse C will require additional funding. 
This is not the recommended alternative. 
Alternative 3  Overlay both Concourse B and Concourse C Roofs 
Cost Implications: $13,183,000 
Pros: 
(1)    Allows the Port to take advantage of existing material that is in good serviceable
condition. 
(2)    Saves money by reusing material. 

Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. 6a                                  Page 5 of 7 
Meeting Date: January 24, 2017 
(3)    Prevents 110,000 cubic feet of insulation that is in good condition from going to the
landfill. 
(4)    Manufacturers have verified that warranty and life expectancy will be the same, 20
year warranty, as on a full replacement.
(5)    Reduces the chance of leaks during construction since existing roof stays in place. 
Cons: 
(1)   A roof overlay, while a common industry practice, is an untried method for the
Airport. 
(2)   When the concourse is due for a new roof, two roofs will need to be removed and a
full replacement will need to be done. 
This is the recommended alternative. 
FINANCIAL IMPLICATIONS 
Cost Estimate/Authorization Summary              Capital        Expense           Total 
Concourse C 
COST ESTIMATE 
Original estimate                                 $5,596,000               $0      $5,596,000 
Previous budget adjustments                     $325,000              $0       $325,000 
Amount to be expensed due to termination      $(350,000)       $350,000              $0 
Revised budget / Authorization                  $5,571,000        $350,000      $5,921,000 
AUTHORIZATION 
Previous authorizations                          $5,571,000        $350,000      $5,921,000 
Current request for authorization                         $0               $0               $0 
Total authorizations, including this request       $5,571,000        $350,000      $5,921,000 
Remaining amount to be authorized                    $0             $0             $0 
Concourse B 
COST ESTIMATE 
Original estimate                                 $7,262,000               $0      $7,262,000 
AUTHORIZATION 
Previous authorizations                          $1,236,000               $0      $1,236,000 
Current request for authorization                $6,026,000               $0      $6,026,000 
Total authorizations, including this request       $7,262,000               $0      $7,262,000 
Remaining amount to be authorized                    $0             $0             $0 


Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. 6a                                  Page 6 of 7 
Meeting Date: January 24, 2017 

Annual Budget Status and Source of Funds 
Concourse C: 
The Concourse C Roof Replacement Project (CIP #C800702) is included in the 2017-2021 capital
budget and plan of finance with a budget of $5,921,000. The first project budget increase
(during design authorization) covered an increase in scope due to added skylight replacement.
The funding sources will include the Airport Development Fund and existing revenue bonds. 
Concourse B: 
The Concourse B Roof Replacement Project (CIP #C800770) is included in the 2016-2020 capital
budget and plan of finance with a budget of $7,262,000. The funding source for this project will
be the Airport Development Fund. 
Financial Analysis and Summary 
Project cost for analysis              $13,183,000 
Business Unit (BU)                  Terminal Building 
Effect on business performance     NOI after depreciation will increase 
(NOI after depreciation) 
IRR/NPV (if relevant)                N/A 
CPE Impact                       $0.03 in 2018. 
Future Revenues and Expenses (Total cost of ownership) 
The new roof system is not expected to have significant repair costs for the first 15 years. Preplanned
preventive maintenance tasks, and therefore costs, will be consistent with the current
maintenance program. Unplanned reactive maintenance call-outs, and those associated repair
costs are expected to be avoided in future years. 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
March 8, 2016  The Commission authorized design of Concourse B 
February 29, 2016  The Commission authorized construction for Concourse C 
May 19, 2015  The Commission authorized design of Concourse C 
June 10, 2014  the Commission authorized design funds for the 2014-2015 Roof
Replacement project. 
April 1, 2014  the Commission authorized a budget increase of $219,000 and execution
of a major public works construction contract with the low responsive and responsible
bidder for the Concourse D roof replacement. 
January 28, 2014  the Commission authorized construction funds for the Concourse D
roof replacement. 
July 9, 2013  the Commission authorized design funds for the Concourse D roof
replacement. 

Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. 6a                                  Page 7 of 7 
Meeting Date: January 24, 2017 
January 8, 2013  the commission authorized construction funds for the North End Main
terminal roof replacement. 
January 24, 2012  the Commission authorized construction funds for the Fire Station
roof replacement. 
July 26, 2011  the Commission authorized design funds for the second phase of the
Airport re-roofing program including design of the Fire Station and North End Main
Terminal roof replacements. 
November 30, 2010  the Commission authorized construction funds for the South End
Main terminal roof replacement. 
April 27, 2010  the Commission approved design funds for the South End Main terminal
roof replacement. 
September 22, 2009  the Commission was briefed on the facility renewal project that
was necessary in future years. The Airport re-roofing program was included in the
presentation. 












Template revised September 22, 2016; format updates October 19, 2016.