Facade Restoration of the Wilshire Boulevard Temple

Figure 1 – Finished south-facing façade, main entry.
Figure 2 – Cracked and
peeling paint.
Figure 3 – Friable weathered
and cracked surfaces.
10
•
Interface
T
he Wilshire Boulevard Temple at 3663 Wilshire Boulevard in Los
Angeles, California, was the first synagogue built in Los Angeles and
was dedicated in 1929. Designed in the Byzantine architectural style,
it is constructed of concrete with a painted Portland cement stucco
exterior (Figure 1).
Unfortunately, the building had experienced water infiltration into
the interior, believed to be from cold joints in the concrete placement and cracks in
the exterior concrete and stucco fabric. Over time, many surface treatments had been
applied in an attempt to abate the water infiltration.
In 2011, Levin & Associates Architects was consulted. Examination showed the
general condition of the painted surfaces demonstrated adhesion failure, blistering,
peeling paint layers, open cracks, faded color, and pollution discoloration (Figure
2). The appearance hinted at a rough, unevenly textured substrate underneath.
Unpainted concrete surfaces
were badly weathered, revealing
coarse aggregates and friable
surfaces (Figure 3). The impact
of these conditions diminished
the beauty of the architecture,
lending an unnatural look to
the cementitious and stone construction.
An examination of the
façade revealed a collection of
many different coatings and
water-repellent
strategies,
ranging from Tung oil/cement
paint, asphalt tar, and epoxies
to oil- and water-based polymer
paints (Figure 4). These paints
May/June 2016
and treatments form a continuous film or ly high vapor permeabiliskin that prevents moisture from entering ty. Sol-silicate coatings are
the cementitious substrate. Openings in unaffected by acids, UV
this film—whether from cracks in the exte- exposure, or airborne polrior concrete and stucco fabric, failed flash- lutants.
ings, or open caulk joints—permit water to
The renovation process
enter by capillary action. Conversely, these was to remove the old paint
multiple layers of film-forming treatments layers, make concrete and
serve to block vapor permeability, trapping stucco patch repairs, fill
moisture within.
cracks, and recoat with a
In nature, substrate humidity will sol-silicate mineral coating.
attempt to find equilibrium with the humid- Exposed concrete surfaces
ity of the surrounding air. This is beneficial would receive a 100%
to maintain dry mass masonry, stucco, active-ingredient silane
and concrete. For the Wilshire Boulevard water repellent. Friable,
Temple, it is a problem. Solar surface heat- exposed concrete surfaces
ing is one of many factors that contribute would be stabilized with a
to the movement of moisture in and out of consolidation product and
mineral substrates. As the sun warms sur- protected with the same
faces, water vapor will move to the warmth water-repellent treatment.
where it is trapped by the multiple paint
The Byzantine revival
layers. On cool nights, the water vapor will dome is a large mass at
condense to a liquid against the paint film. 100 feet in diameter and
If water continues to come into the façade, climbing to a height of 135
these thermal cycles will eventually cause feet. Over time, cracks and
the coating film to delaminate, blister, peel, spalls developed through
or crack so that the water vapor can escape. natural stresses and therEvidence of this phenomenon was observed mal movement in the conat the Temple.
What was needed was
a highly vapor-permeable
decorative finish that would
protect against water intrusion while complementing
the architecture and natural beauty of the temple.
For this purpose, Levin
& Associates chose a solsilicate mineral coating
system composed of a
group of complementary
water-repellent and stuccorepair products for functional performance and
aesthetics that met the
requirements.
Sol-silicate mineral
coatings are made of sand,
potassium carbonate, and Figure 5 – Some paint and tar remained after stripping.
water. Upon application,
they penetrate the surface by capillary crete shell and the hard stucco layer. After
action and, in a chemical reaction, miner- the paint coatings were removed, the conalize the coating with the substrate. The crete and stucco revealed surface cracks
unique sol chemistry provides mechani- from hairline to 1/8 inch wide, with some
cal bonding over acrylic- and resin-based cracks extending through the concrete shell
paints. The resulting crystalline mineral to the interior space.
surface has millions of distinctive irregularThe coating surfaces were stripped of
shaped micropores that naturally resist the previous coats of paint and rinsed with
wind-driven rain while providing extreme- clean water at 1200 to 1500 psi. Despite
May/June 2016
Figure 4 – Delaminating
paint layers. Photo courtesy
of John Fidler, John Fidler
Preservation Technology Inc.
aggressive paint stripping,
some of the previous water
barrier and paint product
applications remained.
Remnants of asphalt tar
were primed with a specialized stain blocker to prevent bleeding through the
sol-silicate finish (Figure
5). What was left of the
well-adhered acrylic paint,
which constituted less than
one percent of the coating
surfaces, did not require
further preparation, as the
unique chemical and mechanical bonding
properties of the sol-silicate coating permitted application over these remnants.
There were no debonded areas of original stucco per se; however, some stucco
around larger cracks had been forced apart
from the concrete shell. In addition, there
were stucco patches from earlier campaigns
that exhibited poor workmanship where
Interface
•
11
Figure 7 – Nonmoving crack repair drawing,
courtesy of Carolyn Searls, Simpson
Gumpertz & Heger.
Figure 6 – Previous repair to stucco.
no e ffort had been made to match the
patch to adjacent surface textures (Figure
6). These two conditions required removal
and replacement, matching the surrounding
surface textures.
The general contractor reported surface
cracks in some newly placed stucco patches.
These were the result of shrinkage from placing layers too thickly. The warm daily temperatures accelerated surface drying before
the core cured. An adjustment to the placement technique included following maximum recommended
layer thicknesses and curing times, along with moisture curing in hot weather to allow the core of each layer to harden
before the top surface dried.
The surface crack-filling strategy incorporated nonmoving
and moving cracks. Cracks were defined as either hairline or
larger than hairline.
• Nonmoving hairline cracks required no tooling. The
fine-grained mineral fillers in the sol-silicate base coat
would fill them with the brush-and-roller application.
• Nonmoving cracks larger than hairline were tooled to a
V-shape, opening the surface to 3/8 inch wide, creating
a funnel to receive trowel-applied lime-cement glassfiber-reinforced filling mortar (Figure 7). The filling
Figure 8 – Properly repaired crack.
Figure 9 – Properly repaired stucco patch and crack.
12
•
I n t e r f a c e
May/June 2016
mortar had 1/32-inch fine grains to match the surrounding surface texture. The mortar was tooled smooth and left proud of the surface (its plane left higher than the
adjacent surface), allowed to firm up, and then gently wiped with a damp sponge to
blend into the
surrounding
surfaces (Fig­
ures 8 and 9).
Vigilance with
application quality
ensured over-tooled
mortar surfaces (as
shown in Figure 10)
were properly refinished flush to prevent trace shadowing
on the dome’s surfaces.
Practical tests
were required to
determine if throughcracks were static
or moving. A representative throughcrack was select- Figure 10 – Straight edge reveals surface depressions.
ed for examination
Figure 11 – Representative through-crack.
(Figure 11).
Trinty|ERD is pleased to
announce the opening of its new
wind testing laboratory in
Oxford, CT., the latest expansion
in its service offering. Having conducted static uplift testing of
commercial roofing systems for over 20 years, Trinity|ERD now offers
its customers testing to the CAN/CSA A123.21 dynamic wind uplift
resistance standard, which is the only codified wind uplift standard in
the National Building Code of Canada (NBCC 2015).
 One of two laboratories in the world that is ISO 17025 accredited
(IAS TL-689) using equipment commissioned through the National
Research Council of Canada (NRC).
 UL Client Test Data Program Participant (DA2667) for UL TGIK
(static) and TGFY7 (dynamic) uplift certification listings.
 12x24 ft chamber size to mirror historical static testing.
 Criticality analysis for selection of critical components.
 Also ISO 17025 accredited for static wind uplift standards codified
in the International Building Code and Florida Building Code.
- ANSI/FM Standard 4474
- UL 1897
- Florida HVHZ TAS 114, Appendix D & J
 Also ISO 17025 accredited for field (in-situ) static wind uplift
standards.
- ANSI/SPRI IA-1
- ASTM E907
- FM Loss Prevention Data Sheet 1-52
- Florida HVHZ TAS 124
353 Christian Street, Unit 13, Oxford, CT 06478  Phone 203-262-9245  [email protected]
M a y / J u n e 2 0 1 6
Interface
•
13
The plaster surface was removed about
two inches to either side of the crack,
reaching depths varying from ½ to ¾ of an
inch into the concrete substrate. A wood
block, presumed to be part of the original
concrete forming, was revealed, positioned
in the path of the vertical crack. The block
was ground flush to the repair depth, as
complete removal was deemed undesirable.
After the repair surfaces were pre-wetted,
the ½-in.-deep repair area received two
layers of filling mortar and the ¾-in.-deep
repair area, three layers of filling mortar.
Proper curing was observed at each step.
After curing, a hairline crack reappeared at the repaired surface, indicating the through-crack was moving beyond
the thermal stress of the soft lime-cement
render (the filling mortar). The repair procedure was modified to accommodate this
movement with a flexible sealant protected
from weathering with the
sol-silicate mineral coating.
• The crack was
enlarged to ½ in. wide, extending
through the existing stucco layer to a depth of 1 inch into the concrete
shell.
• A backer rod and a ½-in. layer of sealant were placed at Figure 12 – Moving crack repair drawing, courtesy of Carolyn
the bottom of the Searls with Simpson, Gumpertz & Heger.
enlargement and
again at the stucco surface. face and provided a silica chemi• Sand, matching the grain size of the
cal bond for the sol-silicate mineral
surrounding stucco, was pressed
coating (Figure 12).
into the wet caulk surface. The sand
Cracks filled or surfaces finished with
camouflaged the smooth caulk sur- lime-cement render were treated with an
Figure 13 – Typical wall section with filled cracks.
14
•
I n t e r f a c e
May/June 2016
application
of
diluted silicic acid
to open-surface
sinter layers (a
dense sediment
surface
layer
composed of mineral fines, lime,
and cement) to
improve penetration for the solsilicate
mineral coating (Figure
13). The silicic acid
reacts with the
free lime, producing calcium carbonate granules
that are rinsed
from the surface
with clean water.
This reaction with
lime neutralizes Figure 14 – Finished southeast corner façade.
the silicic acid.
The sol-silicate mineral-coating system a sol-silicate top coat without the mineral
comprised a sol-silicate base coat having fillers. The mineral fillers function to fill
mineral fillers in grains up to 1/32 in. and hairline cracks, to help soften the uneven
textures of the weathered surfaces, and to
blend the crack repairs and stucco repairs
into the façade for an overall harmonized
SO YOU DON T TAKE YOUR LAST
USM-IBC GUARDRAIL
COST EFFECTIVE
PERMANENT GUARDRAIL
May/June 2016
Our unique mounting and upright design
allows our guardrail system to remain in place
whether it’s a complete re-roof project, edge
metal replacement, equipment maintenance,
facility lighting or security camera work. Our
guardrail remains in place providing
full-perimeter fall protection.
Custom designed to meet and exceed OSHA,
Cal-OSHA, ANSI/ASSE and
USACE standards
Interface
•
15
chemically cure for a minimum of 12 hours.
Three years later, the repairs and
sol-silicate coating are in perfect condition
(Figures 1, 14, and 15). In this climate, the
sol-silicate coating system will protect the
temple for decades. At the end of the coating’s service life, the surfaces are simply
cleaned and recoated; stripping is never
required.
Figure 15 – Finished east façade.
appearance while respecting the character
of the aged structure.
The base coat was diluted ten percent with a sol-silicate dilution to counter
the absorbency of the coating surfaces to
ensure complete mineralization with the
substrate. The top coat was applied undiluted to ensure color consistency. Although
sol-silicate coatings dry to the touch before
ten minutes, each coat was allowed to
Tom Tipps is a
product special­
ist and technical
advisor with KEIM
Mineral Coatings
of America, Inc.
Passionate about
old buildings and
structures
that
form the history of
people and hab­
itation, he helps
Tom Tipps
develop strategies
that remain faithful to the design intent and
function of buildings and reduce costs while
providing healthier working, learning, and
living environments.
Stucco and Exterior Finish
Cladding Systems
An RCI, Inc. Educational Program
August 25-26 | Phoenix, AS
The Stucco and Exterior Finish Cladding Systems course is the second exterior-wall-specific course
that builds on the fundamentals presented in the Exterior Walls Technology and Science program.
The purpose of the course is to provide essential information on material properties, design principles, evaluation techniques, and repair methods for stucco and EIFS.
Topics covered in this course include sound transmission, thermal bridging, coatings, testing methods,
and the various codes and standards impacting stucco and EIFS systems.
Masonry Wall Systems
August 23-24
Phoenix, AZ
Also offered at the same location:
16 CEHs | RCI Member Rate: $500
To register, visit: www.rci-online.org/education.html
16
•
Interface
RCI, Inc.
800-828-1902
May/June 2016