The Guaranty Building: The Restoration of a Terra Cotta Landmark - - PowerPoint PPT Presentation

The Guaranty Building: The Restoration of a Terra Cotta Landmark

Student Scholar: Jon Sargent Savannah College of Art and Design Candidate, Master’s of Historic Preservation

Photo by Jim Cavanaugh

Overview

• I. Building Details
• II. Restoration Details
• III. Contributing Factors to Terra Cotta’s Survival:

Original Design

• a. Building Siting
• b. Unglazed Terra Cotta
• c. Anchoring System
• d. Recessed Window System
• IV. Contributing Factors to Terra Cotta’s Survival:

Restoration a. Crack, Surface and Joint Repair b. Corrosion Prevention

• c. Material Matching
• V. Conclusion

Photo by Jim Cavanaugh

Building Details

• Pinnacle of Louis Sullivan’s work
• Early steel skyscraper
• Downtown Buffalo
• Constructed 1896

(Prudential Building)

• 13 stories
• Northwestern Terra Cotta Co., Chicago
• 1974 – Fire (30% occupancy

pre-fire/15% post-fire)

• 1975 - NHL Designation

Restoration Details: 1980

1980: Initial Restoration

• Cannon Design
• Scope of work:

– Replacement of all windows – Restoration of terra cotta at lower two floors – 60-80 locations of tile repair/ replacement – Cleaning of façade

Photo by Pat Bazelon Photo by Pat Bazelon

1980 Restoration

• Complete cleaning of two facades

– Prosoco masonry cleaner – Pressure wash (750-1000 psi), bristle brushes

Photo by Pat Bazelon Photo by Pat Bazelon Photo by Jon Sargent

Restoration Details: 2002

2002: Second Restoration

• Hodgson Russ purchases building

and funds restoration

• Flynn Battaglia Architects
• Swing staging used for window

and minor cornice repairs

Photo by Michael Lennon, Flynn Battaglia Architects Photo by Michael Lennon, Flynn Battaglia Architects

Restoration Details: 2007-2010

2007-2010: Third Restoration

• Flynn Battaglia Architects
• Morris Masonry Restoration, LLC
• Details:

– Mast climbing scaffold tower anchored to building – Nearly all replacement tiles occurred at floor level where water infiltration had

• ccurred

– Petrographic testing in some cases to match makeup of mortar – Popped tiles at column due to rust jacking – Repairs to terra cotta at first two floors

Photo by Michael Lennon, Flynn Battaglia Architects

Factors for Terra Cotta Survival: Original Design

• Building siting
• Nature of unglazed terra cotta
• Successful anchoring system
• Recessed window system

Photo by Michael Lennon, Flynn Battaglia Architects

Building Siting

• Decorative facades facing

North and East – Lee side of prevailing winds – Protection from elements coming off of Lake Erie

• Focus on city rather than lake

1849 Map of Buffalo, www.buffaloresearch.com

Unglazed Terra Cotta

• Manufactured in Chicago

– Northwestern Terra Cotta known as quality supplier with 500 employees at that time

• Unglazed 4” terra cotta tiles
• Building allowed to breathe, similar to

brick construction

• Material worked hand-in-hand with

surrounding mortar

Photo by Jon Sargent

Anchoring Systems

• Primarily built-in masonry with outrigger elements (Transitional phase)

– Mortar packed tight (8 inch thick typical) – Surrounded steel angles and j-hooks – Steel cramps welded back to steel at cornice, tiles notched to sit on flange of I-beam

Tile failure at steel outrigger prior to 2007 restoration

Photo by Michael Lennon, Flynn Battaglia Architects

Damaged tiles showing built-in masonry attachment

Photo by Michael Lennon, Flynn Battaglia Architects

Built-in Masonry Steel J-Hooks

Elements from Typical Terra Cotta Applications

Anchoring Systems

Photos care of Jeff Morris, Morris Masonry Restoration, LLP

Recessed Window System

• 8” setback at windows
• Originally painted yellow pine
• Replaced with mahogany sash

with thermal glass in 1980

• Lion’s head gargoyles to divert

water at cornice windows

Photo by Michael Lennon, Flynn Battaglia Architects Photo by Mary Ann Sullivan Photo by Sarah Reid, Flynn Battaglia Architects

Factors for Terra Cotta Survival: Restoration

• Crack, surface and joint repair
• Corrosion prevention
• Material matching

Photo by Jim Cavanaugh Photo by Pat Bazelon

Crack, Surface, and Joint Repair

• Hairline cracks at nearly all steel columns

– No structural concerns – Significant cracks: Silicone injection with color match

• Surface rust at columns and cornice

Photos by Michael Lennon, Flynn Battaglia Architects

Crack, Surface, and Joint Repair

• Removal of past joint treatments

– Urethane used in joints at 12th and 13th floor in 1960s – Alligatored surface/ flowing out of joints

• Original: Local mortar with classic 1:1:6 ratio
• Restoration: Jahn mortar

– Different colors used depending on surrounding tiles – 200 areas of application (none larger than 6”)

Photo by Michael Lennon, Flynn Battaglia Architects

Corrosion Prevention

• Tile failures at cornice and column surround both linked to rust jacking

– Steel cramps primary culprit at cornice

• Steel exposed by failed tiles painted with zinc-rich primer
• Cramps replaced with stainless steel counterparts

Photo by Michael Lennon, Flynn Battaglia Architects

Material Matching

Photo by Pat Bazelon

• Compatibility of materials
• Sandblasted finish in areas where tiles were blasted in 1958
• Thoroughbody clay in first two restorations
• Red thoroughbody clay with red slip used in 2007 restoration
• Color matching
• Faced issues during 1980 restoration
• 12 different shades in color (purple to red to bright orange)
• Use of cleaned control samples

Photo by Jon Sargent

Conclusion

• Ideal siting and selection of materials

based on environmental conditions

• Built-in masonry system successful at

preventing water infiltration

• Careful attention to compatibility of

materials

• Owner’s dedication to building

preservation and maintenance

Photo by Jon Sargent

Credits

Thank you to the following parties for providing valuable information and images:

• Flynn Battaglia Architects
• Morris Masonry Restoration LLC
• Boston Valley Terra Cotta
• Hodgson Russ LLP

Photo by Michael Lennon, Flynn Battaglia Architects