ny life project
DESCRIPTION
The investigation and remediation of the failing gilding on the roof and lantern of the NY Life headquarters in New York City in 2007.TRANSCRIPT
Fading Lustre: Investigation and
Remediation of the Golden Roof and Lantern
atop the NY Life Headquarters in New
York CityPresented by Michael Kramer, President, The Gilders’
Studio, Inc.
APTI Meeting in Montreal, October 15, 2008
Designed by Cass Gilbert
Opened in 1928 the building featured 35 occupied floors with a crenellated masonry roof. On top of the roof was a 65’ tall gilded bronze lantern.
Another view of the roof.
Leaks were always a problem.
Roof was re-designed in 1967
35th floor was removed.
22,000 enameled gold tiles were installed.
Lantern was made watertight and re-gilded
After 30 years the finish on the tiles began to fail and were replaced with all new tiles in 1996.
Roof in 2004
After four years the gold glaze on the new tiles showed signs of
failure.
While the tiles are initially fired at over 2,000° F, the gold enamel glaze is only fired at @ 1,200 °F.
Changes in the glaze formula from 1967 to 1995 may have also played a factor.
An investigation and testing program was initiated in 2001.
Observations in situ
Note the relationship between the areas of least gold and the wash patterns of the rain.
Potential Avenues of Failure
Note crazing in gold glaze.
Uneven application of the glaze.
Investigation and Testing
Various approaches were explored 1. New gold tiles – Manufacturer no longer offered them.
2. Replace tiles with copper shingles and then gild - $$$$!!!!
3. Apply gilding system to the existing tiles- Testing of various abrasive and priming/gilding systems was approved.
Tile blasted with two different abrasives
Accelerated Weathering to ASTM standards and more
QUV Ultraviolet and Freeze Thaw.
Salt Fog
Acid Deposition
“Quenching” i.e. raising the samples to high temperatures and quenching with water to stress the system beyond conventional freeze thaw.
Testing was completed in 2003 - Six systems were tested and one in particular outperformed the others.
Notice to Proceed – late 2006
Completion slated for October 2007.
Scaffold the roof , lantern and tourelles
Remove failing gold glaze layer
Strip lantern and make repairs
Prime and re-gild all elements
23 levels of scaffolding
January 1, 2007, New VOC regulations– priming system from 2003 became illegal.
Rush Testing – 3 additional priming systems
Accelerated weathering of the systems while the scaffold was being designed and built.
Hydraulic adhesion tests after weathering provided quantifiable results.
New VOC Compliant system performed better than the one originally chosen.
Paint manufacturer supplied a 5 year warrantee based on the test results.
Enclosed with mesh
Tiles blasted with Sponge Jet system
Removed the gold glaze layer without damaging the fired tiles.
Recyclable - Collect and re-use up to 8 times
Virtually no dust
Blasted tiles
Application of epoxy primertwo coats - brushed and rolled
The Lantern
65 feet tall – originally gilded
Top 40’ is cast bronze
Lower portions are copper from 1928 and lead coated copper from 1967
Different coatings on the lantern
Lantern DetailsBandaids from 1996
and 1967
Inappropriate repairs
Unexpected Conditions Bituminous tar layer from 1967, covered with powdered lead then lead paint, size and gold leaf.
In 1996 repainted over the gilding, then new gilding atop
140x
Stripping options for the Lantern
Original Gilding from 1928
AlternativesHeatguns Advantages
Controlled release of lead
Worked in one pass
After Sponge Jet blasting
Lead coated copper chemically stripped
Deterioration due to previous interventions
Repairs to the bronze
Primed Bronze
The Gilding Process
Sizing
Slow oil size tinted with oil color
Gilding
Using 195mm ribbon leaf
Sized Finial
Gilding the Finials
Completed Finial
Scaffold Dismantle
Tile touch up and replacement
Summary of the Priming and Gilding Process
Tiles – 1.Blasted with Sponge Jet system2.Primed with 2 coats of epoxy3.Sized with slow oil size
Lantern –1.Heat stripped and blasted with Sponge Jet system.2.Bronze- primed with zinc chromate3.Lead coated copper- primed with epoxy.
All surfaces had a slow oil size applied followed by 23.75KT gold leaf in a extra heavy weight.
Expected service life – 35 years
Challenges of the Project
Determining the avenues of failure and proper remediation
Working in Manhattan
Adapting to new VOC standards “on the fly”
Dealing with the lantern nightmare