CARLETON HART ARCHITECTURE - Portland, Oregon

MULTNOMAH COUNTY

MEAD BUILDING

Portland Metro Area, Oregon

Eco‐Roof Final Report

February 2011

CARLETON HART ARCHITECTURE

Architecture Planning & Development

322 nw 8th avenue, portland, oregon

Page 2 Mead Eco-Roof Final Report

MEAD CARLETON HART ARCHITECTURE

TABLE OF CONTENTS Table of Contents ................................................................................................................ 2

Project Team ....................................................................................................................... 3

Summary ............................................................................................................................. 4

Project Description .............................................................................................................. 5

Re Roof ............................................................................................................................... 7

Eco Roof ............................................................................................................................. 8

Project Budget ................................................................................................................... 16

Conclusion ........................................................................................................................ 17



PROJECT TEAM Multnomah County Facilities and Property Management Owner Alan Proffitt, Project Manager KPFF Consulting Engineers Engineer Anne Monnier, Structural Engineer MacDonald Environmental Planning, PC Landscape Architect for Feasibility Study Laurel Macdonald Bonnell, Principal Green Living Technologies, LLC Green Roof Installer George Irwin, Principal Snyder Roofing of Oregon, LLC General Contractor Dave Layton, Project Manager Carleton Hart Architecture Architect Brian Carleton, Principal Scott Palmer, Project Manager Lisa Goslow, Project Architect



SUMMARY In 2010, the aging roof of the Mead Building, a Multnomah County facility in downtown Portland, Oregon was in need of replacement. Multnomah County Facilities and Property management engaged Carleton Hart Architecture to assess the condition of the existing roof, review replacement options and to study the feasibility of including an eco-roof as a potential component of a new roofing assembly. Carleton Hart Architecture consulted with KPFF Consulting Engineers to evaluate the structural capacity of the building’s roof structure to accommodate the additional loads imposed by an eco-roof. The results indicated the capacity of the existing roof structure to accommodate additional loads was very low. An eco-roof could weigh no more than10 to 15 pounds per sf. Macdonald Environmental Planning was asked to accept the challenge of designing an eco-roof system that could meet this stringent weight limitation. Tremco roofing in consultation with Carleton Hart Architecture, provided assistance in selecting and detailing the appropriate roof system for the use with an eco-roof assembly. Based on the findings from the Feasibility Study, an eco roof was installed on the Mead Building during roof membrane replacement and is expected to provide the following benefits:

Protects the roof membrane from UV exposure Protects the roof membrane from thermal shock Reduces expansion and contraction of the roof membrane Provides storm water detention Provides filtering of storm water Provides additional insulation Reduces cooling loads through the damping effect of thermal mass Reduces cooling loads through plant transporation Reduces the heat island affect Provides insect and animal habitat Enhances the appearance of the roof Qualifies for incentives from the City of Portland

Based on a storm water retention study by Green Living Technologies, a 65% storm water retention rate could be expected even though the profile of the medium is very thin. It is still too early to determine this. It is also expected that the overall air conditioning and heating loads will be reduced as a result of the installation of the eco roof.



PROJECT DESCRIPTION EcoRoof Size: 5743sf Project Type: Light weight, panelized pre-planted Zoning and Building The building is located in downtown Portland in the Central Commercial zone (CX). The building currently holds office space and is located within the design overlay district as well as the Central City plan district. Even though the eco-roof is not seen from the street below, it is viewed from the adjacent building windows. As a result of these overlays, the addition of the eco-roof was submitted for a Type II Land-Use Review process. Building Description The Mead Building was originally designed by Doyle, Patterson and Beach Architects in 1911. The building underwent an alteration in 1931 with the addition of the light well. A preliminary structural seismic evaluation was conducted in 1995 by Walker/DiLoretto/Younie. The building is located at 408 SW 5th Avenue. The building is surrounded by on-street parking and is very close to the MAX lightrail system. The existing roof structure consists of a 7-inch thick two-way concrete slab system. The column bay spacing is approximately 19'-2" in both directions, 3-inch deep by 5'-0"x5'-0" octagonal shaped drop panels are placed at each concrete column to strengthen the slab. The ceiling system below the roof slab currently consists of the original lath and plaster ceiling with a more recent suspended acoustical tile ceiling system located approximately 18-inches below the plaster ceiling. The double ceiling system utilizes much of the load-carrying capacity of the slab. The upper mechanical room penthouse roof and the main level of the roof is the location of the proposed eco-roof. The combined overall rooftop square footage is 8740 square feet with 1488 square feet of the total square footage existing on top of the penthouse. The lightwell houses a skylight and has a narrow walkway around the area which is used for maintenance. There is a small mechanical room penthouse which houses equipment and accessories. These two areas do not contain the eco-roof. The main roof level houses the bulk of mechanical equipment and accessories. Two main roof drains and several roof ladders are located at this level. There are water pipes and electrical conduit located across the main roof level. The location of the eco-roof system will allow for adequate access to all mechanical equipment and accessories. There are no plumbing outlet spigots located on the roof but, there is water hookup inside the penthouse adjacent to the main roof level. Main access to the roof is through a "man door" from this penthouse.



Existing Mead Roof prior to eco roof installation.

New mechanical unit, piping and equipment maintenance clearances.



RE ROOF The existing roofing system consisted of a single ply roof membrane and the insulation was mechanically fastened to a concrete deck. Due to the roof leaking at random, the membrane was scheduled to be replaced. A new built-up 3-ply asphalt roof was installed along with new rigid insulation and counter flashing. An existing roof top mechanical equipment was replaced. A fall restraint system was installed at the upper mechanical room penthouse to meet safety requirements for the eco-roof. System components The Mead Building was re-roofed by Snyder Roofing Company of Oregon. The roofing product installed was manufactured by Tremco. The new roofing membrane is composed of the following:

Tremprime WB water based primber BURmastic Composite Ply HT (3 plies) - cold applied PowerPly Supreme FR Root barrier and Tremco Polymat Loose layers of DOW Plazamate extruded insulation T-Clear Light Guard PMR insulation pavers at walkways LG PMR board with Tremco ICE reflective coating

Installation of built up roof.



ECO ROOF The existing roof membrane was scheduled for replacement. Early in the study it became apparent that the installation of the eco-roof would need to be completed as a part of the re-roofing process and that the identified eco-roof system will need to be light-weight to meet structural requirements. A pregrown palletized system was chosen to meet the stringent weight restrictions and soil depth considerations. Eco-Roof Products The Feasibility Study prepared by Carleton Hart Architecture and MacDonald Environmental Planning, assessed two eco-roof systems. The first system considered, was Columbia Green Technologies, a local company out of Wilsonville, Oregon. The second system was Live Roof from Spring Lake, Michigan partnered with Blooming Nursery located in Cornelius, Oregon. These systems are “tray” systems and are applicable to roof dead loads of 20 pounds per square feet or more. These systems were compared based on early findings of structural capacity. The concrete core tests have shown that the dead load capacity is 10 pounds per square foot for the eco-roof system. As a result, an examination of a lightweight system by Green Living Technologies was the recommended system for this application, which at the time of the project and bidding was the only system that could meet the saturated weight requirements. System components The Mead Building required the installation of a lightweight system due to structural constraints. The weight was limited to a maximum, fully saturated weight of10lbs/sf on the main roof and 15lbs/sf on the penthouse. In the Feasibility Study, the panel system Green Living Technologies, LLC based in Rochester, New York, was recommended. The proprietor, George Irwin, is recognized internationally. Green Living Technologies provided an integral, panelized system. The components are as follows:

1-2" of proprietary lightweight growing media Pre-planted plugs grown at a local, certified nursery A light weight, plastic drain carrier and water retention mat Filter fabric Drain mat Metal edging and drip irrigation



System Specifications

GLT -Detail of Panel System Installation Method The panels were installed pre-planted and craned up to roof level. The panels can be temporarily stacked without long term injury to the plantings. The panels are lifted into place by hand and the edges are "snapped" together to make a large, integral mat of plantings and placed over a filter fabric and drain mat. The edging is metal and keeps the panels from shifting over time.

Plugs grown on the panels at Van Essen Nursery



Crane pick at the Mead Building.

Stacked panels prior to placement.



Typical pre-planted panel.

Placement of the panels on the main roof.



Metal edging at penthouse level.



Irrigation Due to high temperatures on roof tops during the summer months, a permanent irrigation system was installed to allow for successful plant establishment. The plantings are irrigated with an automated drip system. The controller is programmable and the area is divided into six zones. The controller has the capacity to tie into a computer system allowing the irrigation for this roof to be monitored remotely by the County.

Drip system at time of installation. Plantings

The eco roof is composed of several different species of sedum. The plant list is as follows:

Delosperma nubigenum - drought tolerant 3,290 plants Sexangulare 3,220 plants J. Creech - drought tolerant 2,590 plants Hybridum immergrunchen 2,520 plants Sedum acre "Aurea" 25% main roof area Sedum Stefco 25% main roof area Sedum Boehmeri 25% main roof area Sedum Spathifolium 25% penthouse roof Sedum Oreganum 25% penthouse roof Sedum Reflexum "Blue Spruce" 25% penthouse roof Sedum Reflexum "Angelina" 25% penthouse roof



Typical pre-planted panel on filter fabric.

Overview of plantings at main roof at time of installation.



Overview of plantings at penthouse roof at time of installation.



PROJECT BUDGET Cost Component Breakdown The following table is a cost breakdown for the project: Components Cost Design Team and Consultants $ 30,433.00 Re-Roofing and Sheet Metal (permit n.i.c.) $ 305,036.00 Eco-Roof system $ 200,758.00 Actual Eco Roof Cost $ 34.84/sf Cost Comparison from the Feasibility Study

Columbia Green Technology: $21-23.00 sq.ft. ($104,391-114,333.00)

LiveRoof: $22-24.00 sq.ft. ($109,362-119,304.00)

Green Living Technologies $14-18.00/sq ft. ($69,595-89,478.00)



CONCLUSION During construction Green Living Technologies stated that they felt only a limited number of species would be viable on the roof in the Northwest. The design team disagreed and pushed for more species diversity. The thought is that the increase in diversity allows for greater plant success over time. There was much debate over this compounded by the fact that the company is not local. Several nurseries were contacted to determine a wider diversity of sedum that would thrive in the thin medium. This discussion led to a delay of the project installation from spring to the fall of 2011, as additional plants needed to be obtained from a local source. The panels were initially pre-planted at a local nursery and allowed for the roof to become established early, prior to winter. This is already evident from the plant spread. New budding was observed a few days after installation and growth is healthy. The Mead Building roof can be seen from several buildings, including a hotel across the street. Several individuals observed installation. The eco roof's immediate benefit is an improved view for the occupants in neighboring buildings. Initial studies by Green Living Technologies, based on the company's other projects, anticipates the reduction in storm water may be as much as 60%. Although this is Green Living Technologies first project in Oregon, they have demonstrated this success in other parts of the country. It is predicted, based on findings at other buildings owned by Multnomah County, that the life of the roof membrane will be extended due to protection from UV exposure and thermal shock. The county is also predicting there will be a decrease in cooling loads although this will be difficult to measure in this particular project since the cooling tower was upgraded and has a much higher efficiency than the older cooling tower. Unfortunately there will not be any data for comparison prior to installation of the green roof.

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CARLETON HART ARCHITECTURE - Portland, Oregon