Cherberg Draft Report · Drawing Name Drawing Number 0303 08 November 2005 Date Revision Descriptio n Archit ect's Stamp Archit ect Proje ct Consultant's Stamp Consultant e: cardw

JOHN A. CHERBERG BUILDING EXTERIOR SURVEY Architect's Project Number 0303.95

23 June 2006

CardwellArchitects

1221 Second Avenue, Suite 300 Seattle WA 98101-2925

(206) 622-2311 f (206) 442-9165 cardwellarchitects.com

John A. Cherberg Building Exterior Survey

Cardwell Architects surveyed the exteriors of the O'Brien Building and the Cherberg Building on 16, 17, and 18 May 2006. Mark Liebman, of Krazan and Associates, joined us on the 16th and 18th to review mortar conditions and to take mortar samples for lab analysis. General Administration provided two staff and a man lift to support the work. On the Cherberg Building, we surveyed the stone and mortar and will make recommendations for repair and maintenance. Attached are a summary of our findings and a mortar analysis summary from Krazan and Associates. Granite Stone Base The granite stone base is typically in good shape, however, mortar should be repointed. Soil should be removed from stone and new grade should be created below granite base at waterproofed concrete. Local site regrading may be required to achieve necessary positive slope away from building base.

Photo: 90 Sandstone Building Envelope The Wilkeson sandstone face of the Cherberg Building is typically in good shape. Locations where there is surface stone deterioration are limited and obvious. Previous studies indicate localized spalling, and this is normal for sandstone panels of this age. More serious deterioration is located at expected locations such as beneath the large gutter at the cornice and at the portico ceiling. These locations receive penetrating water intrusion from above. Seeping moisture brings minerals from inside the stone to the stone surface, and there is no opportunity for wind and rain to wash these stone surfaces clean. The surfaces above should be repointed and repaired, and the areas below should be cleaned. The stone does not show significant damage from previous repointing jobs. Joint profile is typically beaded, but there are locations, such as at horizontal details and at the parapet, that are flush joints. Stone cracks are identified on the attached drawings. There are also a few locations where stone has chipped at corners and is missing. Cracks should be ground out and repaired with a color-matched stone repair mortar such as Jahn M70. Missing stone should be replaced with a color-matched stone repair mortar such as Jahn M70.

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Photo: 136 and 137 Mortar There are at least three types of mortar installed on the Cherberg Building. There are also two types of mortar joint profiles, a beaded joint and a flush joint. These profiles are in predictable locations on the Cherberg Building. The first mortar is the original mortar, and is only visible in a few isolated mortar joints. This mortar is typically gray, appears to have cement in it, and contains black sand that looks like pepper flakes. The second mortar is a repointing mortar that was installed on 95% of the building mortar joints, all at the same time. The mortar looks like a hydraulic lime mortar and has an ivory color. This mortar is typically in good shape, with localized deterioration. The third mortar is US Heritage Hydraulic Lime mortar installed at window jamb and head, as well as pilaster to wall joints beneath the two portico roofs. This mortar installation was performed by the GA, and is of varying workmanship quality. Repointing is required in approximately 20% of the building mortar joints. Mortar joints are typically in the worst shape in the vertical joints where the pilasters meet the wall, and at all window jambs and head joints. Horizontal details, such as the cornice/gutter and other horizontal trims are also candidates for the first attention for repointing. The attached report from Krazan & Associates provides an analysis of the original mortar, as well as the repointing mortar. Typically we would recommend matching the original mortar. On the Cherberg Building, however, there is a nearly complete repointing job that is in acceptable condition which does not match the appearance of the original mortar. Instead of removing all of this competent mortar, we recommend that the new repointing mortar match this ivory repointing mortar.

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Photo: 85 Parapet and Horizontal Details Parapets have relatively new, pvc membrane roofing and stainless steel parapet caps protecting the hidden vertical surface and sky-facing surface. The remaining exposed stone surface has eroding mortar as well as sealant in many of its mortar joints. Horizontal details have horizontal and vertical joints that receive a large amount of weather. These joints should be repointed to keep weather out of the building and to protect adjacent stone.

Photo: 144 Penthouse There was masonry work at the penthouse while we were surveying. Masons were replacing several of the south-facing stones with new louvers. The mortar on the penthouse was not uniformly repointed like the rest of the building below the parapets. Repointing work in this area is random, and has both flush and beaded joints. The penthouse shows signs that its weather exposure contributes to faster mortar erosion, and the whole structure should be repointed to improve its weather performance.

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Photo: 88 Gutters & Downspouts Gutter liner and copper are to be replaced as part of the current construction project. Provide regular gutter, drain, and downspout cleaning and maintenance - minimum twice a year in late spring and late fall. In addition, there are two surface drains on the base of each portico. These should also be part of a regular maintenance cleaning schedule.

Photo: 160 Stair Structure, North Side of Cherberg Building The mortar in the entry stair structures is missing or deeply eroded and should be repointed.

23 June 2006 4 of 6


Photo: 138 Stone & Mortar Cleaning Areas near pediment roofs and at the parapet/cornice level are the typical locations of black staining. Biological growth is typically found on the north elevation details and especially at the north elevation parapet. More staining is also prevalent at the other two horizontal detail levels. The building appearance would improve dramatically with cleaning, but staining and biological growth should not be priorities at this time. The building should be on a cleaning schedule, and the work should be limited to low pressure (<200 psi) and hot water. Areas with more intense biological growth (parapets) may require a light treatment with a biological cleaner, such as Prosoco BioWash, but biological growth was not dramatic and low-pressure hot water may be sufficient.

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Project Recommendations 1) Use repointing mortar to match most recent repointing mortar. Mortar recipe to be determined

through analysis. 2) Repoint areas that are in worst shape first, which include the vertical joints where the pilasters meet

the wall, and at all window jambs and head joints. 3) Repoint the penthouse mortar joints. 4) Repoint mortar joints at all horizontal details. 5) Repoint parapet mortar joints. 6) Repoint loose or missing mortar over entire building. 7) Repoint entry stair structures, north side of building. Maintenance Recommendations 1) Remove soil at granite base and regrade adjacent soils for positive slope away from building. 2) Provide regular gutter, drain, and downspout cleaning and maintenance - minimum twice a year in

late spring and late fall. Construction Project Cost Estimates Repointing All Mortar Joints – For Information Only 45,370 LF of mortar joints @ $7.15/LF = $324,395.00 Repoint Window Jamb, Head, and Pilaster/Wall Joints 7,340 LF of mortar joints @ $7.15/LF = $52,481.00 Repoint Penthouse Joints 1,255 LF of mortar joints @ $7.15/LF = $8,975.00 Repoint Remaining Damaged Mortar Joints, except Window Jamb, Head, Pilaster/Wall & Penthouse, Approximately 20% of Remaining Mortar Joints (45,370 LF – (7,340 LF + 1,255 LF)) 0.20 = 7,355 LF 7,355 LF of mortar joints @ $7.15 = $52,590.00 Stone Repair, Approximately (14) Locations 14 Locations @$1000 each = $14,000.00

23 June 2006 6 of 6

ArchitectsCardwell

206 442.9165

206 622.2311

Seattle WA 98101

f:

t:

1221 Second Avenue . Suite 300

304 15th Avenue SW

RehabilitationBuilding

Olympia WA 98504

John A. Cherberg

Project Number

Date

Drawing Name

Drawing Number

0303

08 November 2005

Date Revision Description

Architect's Stamp

Architect

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Consultant

e: cardwellarchitects.com

John A. Cherberg

Bid Package #4GA: Project Number: 2004-100

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ArchitectsCardwell

206 442.9165

206 622.2311

Seattle WA 98101

f:

t:

1221 Second Avenue . Suite 300

304 15th Avenue SW

RehabilitationBuilding

Olympia WA 98504

John A. Cherberg

Project Number

Date

Drawing Name

Drawing Number

0303

08 November 2005

Date Revision Description

Architect's Stamp

Architect

Project

Consultant's Stamp

Consultant

e: cardwellarchitects.com

John A. Cherberg

Bid Package #4GA: Project Number: 2004-100

A4.1

EXTERIOR

2ELEVATION: FSCALE: 1/8" = 1'-0"

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8PENTHOUSE WEST ELEV.SCALE: 3/16" = 1'-0"

9PENTHOUSE EAST ELEV.SCALE: 3/16" = 1'-0"



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& A S S O C I A T E S , I N C .

G E O T E C H N I C A L E N G I N E E R I N G • E N V I R O N M E N T A L E N G I N E E R I N G F O R E N S I C I N V E S T I G A T I O N • C O N S T R U C T I O N T E S T I N G & I N S P E C T I O N

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REPORT

TO: Richard Price DEPARTMENT OF GENERAL ADMINISTRATION Division of Facilities Planning & Management PO Box 41001 Olympia, WA 98504-1019

RE: Mortar Analyses and Mix Design for the Cherberg Bldg; Olympia, WA Krazan Project #: 096-06034

Date: June 21, 2006

On May 18, 2006 a visual survey was performed at the John A. Cherberg Building. The purpose of this survey was to identify the original mortar used in the building and to note the areas where repointing mortars and caulking had been installed. Jim Cary of Cardwell Architects led the documentation process. It was determined during the investigation that a significant percentage of the mortar seen in the building is material used for repointing at some previous point in time. The predominance of this material necessitated that it, along with the original mortar, be analyzed as part of the documentation process. As a result of the survey, it was determined that three mortars in the building should be sampled. A sample of the original pointing mortar was secured at various locations along the south and east sides. During this sampling it was noted that the bedding mortar appeared to be comprised of different components, so a sample of this mortar was also secured in these regions. Finally, a sample of the repointing mortar was secured at numerous elevations along the south side. The samples were sent to England for specialized analysis via Differential Thermal Analysis (DTA) and polarized light microscopy, which allow for the most concise evaluation of the binder components of a mortar. Lime, hydraulic lime, and varying cement types are all made by the process of burning limestone. While inherent components in the stone contribute to the characteristics of the resultant material, the temperature at which the material is fired is the defining factor between lime and cement. DTA reverses the process and documents the subsequent breakdown of the materials. What is important about this process is that the evolution of lime to cement has occurred in stages. Limestone fired in a coal or wood burning kiln was rarely subjected to temperatures in excess of 900 degrees C. This resulted in traditional lime that was slaked into lime putty. When lime was fired at slightly higher temperatures (1100 - 1200o C), hydraulic properties became more pronounced and predictable. When temperatures of 1400o C became possible, due to advances in technology, Portland cement became a reality. And, with current cement kilns achieving 1600o C +, a whole new range of cements has been made possible.

Mortar Analyses and Mix Design for the Cherberg Bldg

Krazan Project #: 096-06034 pg 2 of 12

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Turning our attention to the mortars in question, we see in the laboratory results (see appendix), that the components of the original bedding and pointing mortars while similar, do vary. It appears that the bedding mortar may contain a higher percentage of cement in the binder then the pointing mortar. It likewise appears that an effort was made to use a lighter mortar, such as that seen in the O’Brien Bldg, to help disguise the mortar joint against the sandstone background. However, given the extent of the repointing mortar in the building, it seems appropriate to concentrate our analysis on this material. The repointing mortar represents a reasonable attempt to repoint with a material similar to that used originally. The laboratory analysis reveals a binder that has some pozzolanic properties, but not to the extent of modern materials, resulting in a mortar that is not as hard or dense as modern type ‘N’ or ‘S’ material. For this reason, there are a variety of possible scenarios for this mortar. But, the most likely composition consists of lime, white cement and sand. What is somewhat unique, however, about this mortar is the ivory coloration. This may be the result of the sand used for the mortar mix, but may have been influenced by the cement component. It is interesting to note that, while the original mortar features some exposed black aggregate, no attempt to match this appears to have been part of the repointing effort, though the beaded joint finish has been maintained. For any maintenance or replacement pointing at the Cherberg Building, we recommend replicating the appearance and properties of the repointing mortar. The Secretary of the Interior’s Guidelines and the National Park Service Preservation Brief #2 favor matching the original material and, as this previous repointing effort appears to have been guided by this approach, we recommend using a similar material as the baseline for future work. Following is our mortar mix design for this mortar. It should be noted that, as this material contains a percentage of cement in the binder, the standard specifications for repointing on current capitol campus projects would need to be revised. Mortar Mix Design (volumetric): 1 part white Portland cement, 2 parts hydrate lime, 6 parts fine sand After a review of the lab data, we have concluded that the binder proportions noted above should best duplicate the properties of the repointing mortar. It should be noted that achieving the ivory color of the existing mortar may necessitate the use of a coloring agent if a suitable sand cannot be found to replicate the appearance. The manner in which the joint is finished will also be critical to insuring a suitable mortar match, as the beaded joint is a necessary component of the repointing work Therefore, not only will an appropriate color match need to be part of the submittal for approval, but a test section demonstrating the beaded joint should be utilized as part of both the initial acceptance criteria and for reference during the repointing. The option exists to purchase a pre-blended mortar from US Heritage Group that meets the criteria or to mix the material onsite. To insure uniformity, we recommend that site mixed mortar be subject to periodic special inspection during the mixing process. We also feel it would be prudent to include special inspection of the repointing in the project specifications. It is entirely possible that, had inspection been required on other capitol campus repointing programs (specifying an inspector trained in historic masonry techniques and materials), problems associated with some of these previous efforts may have been avoided.



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If desirable, we would be pleased to offer our support to the design team in (re)writing the standard repointing specifications for the GA. With the pending adoption of the Preservation Brief #2 guidelines, a generic specification could be created for the entire capitol campus, or a specific spec written for the Cherberg Bldg. We are confident we could make a significant contribution to either effort.

Mark Liebman Senior Forensic Investigator



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APPENDIX

Laboratory Results



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Documents

Cherberg Draft Report · Drawing Name Drawing Number 0303 08 November 2005 Date Revision Descriptio n Archit ect's Stamp Archit ect Proje ct Consultant's Stamp Consultant e: cardw