3. Development of Backer Board
The first exterior jobs of backer were attempted
with great success. Farrell’s Ice Cream was the
first commercial exterior use of concrete backer
board. No longer in existence, it was located in
Springdale, OH. It was surfaced with ceramic tile.
The first exterior direct applied stucco application
was Queen of Peace Church, Millville, OH. It was
finished with a direct applied stucco and embedded
marble chip finish.
5. Development of Backer Board
Soon after, knowledge of the new material,
and the time savings began to generate great
interest. Demand began to outpace hand
production.
Ted Clear invented the automatic process to
manufacture concrete backer.
Fin Pan, Inc. was begun to manufacture
“WonderBoard”. Modulars, Inc. went into sales
and marketing. The year was 1974.
6. Evolving Backer Board
Backer Board was beginning to catch on outside
out the Cincinnati Tri-State Area although it was
a few more years before other boards began.
Backer Board was produced in various sizes to fit
specific applications:
3’ x 5’ was produced for a tub surrounds
3’ x 64” was produced order to be used for standard stud spacing.
3’ x 4’ was produced for use on floors –
8’ was not available originally and extremely heavy
3’ x 5’ is still the most popular size for residential
construction. Fin Pan still manufactures the various
sizes for ease of installation and less waste on the
jobsite.
7. Evolving Backer Board
USG began producing Durock in 1987. Originally
USG only produced 3’ x 5’. It was not long before
Fin Pan and USG both developed an 8’ backer.
USG developed the 4’ wide format
and Fin Pan developed the 3’ wide.
During this time, the “WonderBoard” name was
sold by Modulars Inc. and rights given to
Custom Building Products to produce.
Fin Pan, Inc. named its board “Util-A-Crete”. It is
produced to the same quality standards as the
original “WonderBoard”.
8. Evolving Backer Board
The focus for most of the board manufacturers was lighter
weight. Experimentation with the core of concrete backer
boards lead USG and Custom to introduce other materials
into their cores in the attempt to lighten and reduce raw
material cost.
Some manufacturers reduced the glass mesh count to reduce
cost. The result is less flexural strength.
Bottom (Fly) Ash from coal fired electric plants and crushed
slag from steel factories were introduced into some board,
evidenced by the “coffee staining effect” or ferrous (rust)
leach.
Fly Ash (top ash) also were introduced into some board. A
cleaner and uncontaminated material fly ash bonds well with
Type 1 Portland Cement and does not produce rust staining.
9. Evolving Backer Board
Gypsum (Synthetic Gypsum) was also used in the
attempt to lighten board weights.
The next change came from a company based in
Canada, Unifix. Unifix introduce polystyrene bead
to its core. A lightweight and easily cutable
material, gained popularity and the attention of
National Gypsum Company. National Gypsum
acquired Unifix US and PermaBase was launched.
Type III Cements requiring high temperature
curing (oven) also is used in some boards as well
as entrained air to make them lighter.
10. Evolving Backer Board
Fiber cement boards were next in the development
path. Originally, not recommended for exterior,
some fiber cement boards are still not recommended
for exterior applications. James Hardie does not
warrant nor recommend HardieBacker for exteriors
Not to be forgotten, gypsum cored boards with
fiber glass wrapped skins began to emerge with
the success of DensGlass Gold for exteriors.
11. The Differences
The changes in the evolution of backer board
are evidenced in the materials composition of
each different type of backer and the effect on
board properties. (Published Values*)
Backer Board Manufacturer Compressive Flexural
Strength Strength
Util-A-Crete Fin Pan, Inc. >2600 psi >1500 psi
ProTEC Fin Pan, Inc. >2600 psi >1260 psi
Durock USG 2300 psi 750 psi
FiberRock
PermaBase Nat’l Gypsum 2250 psi 750 psi
WonderBoard Custom 1250 psi >750 psi
Bldg.Products
12. The Differences
What does Compressive Strength
and Density mean to external uses of
Backer Board?
The higher the compressive strength,
the higher the density.
The higher the density,
the slower the absorption rate.
The slower the absorption rate,
the better the performance in
freeze thaw conditions.
13. The Differences
All Concrete Backer Boards absorb some water.
The absorption of moisture is slowed in boards
that have denser cores. The introduction of
dissimilar materials, like polystyrene can leave
pathways to transmit water.
A more homogenous core will allow materials
to bond more thoroughly, become dense and
resist the absorption of water. The perceived
drawback is that the board is heavy and more
difficult to cut. A moisture barrier is needed with
all concrete based backer boards
14. The Differences
Some of the backer boards that are recommended
for exterior use have gone to a glass mat wrapped
exterior.
Advantages:
Protects hygroscopic core
Protects against core damage
Resists Freeze Thaw
Disadvantages:
Screw Penetration may cause moisture
migration and core degradation
Can not direct apply finishes
15. The Differences
Glass Mesh count also plays a large role in
flexural strength and values.
Woven fiberglass embedded has the
highest flexural strengths. They provide
the best tension and compression
assembly translating to flat backer board.
Some manufacturers have an 8 x 8 count weave,
some 8 x10, 8 x 12 and some 10 x 16. Flexural
strength numbers directly correlate to weave
counts.
16. The Differences
Backer Board Manufacturer Compressive Flexural
Strength Strength
Util-A-Crete Fin Pan, Inc. >2600 psi >1500 psi
ProTEC Fin Pan, Inc. >2600 psi >1260 psi
Durock USG 2300 psi 750 psi
FiberRock
PermaBase Nat’l Gypsum 2250 psi 750 psi
WonderBoard Custom 1250 psi >750 psi
Bldg.Products
17. Current Accepted Exterior
Assemblies
These two assemblies are similar in
their details.
One has a polystyrene insulation
board in the assembly
In the assembly:
Gypsum Board (Int.)
Stud Framing & Cavity
Cavity Insulation
Structural Sheathing
Moisture Barrier
Concrete Backer Board
Mesh Joint Tape
Low Density Polystyrene Insulation
Mesh Reinforcement
Base Coat
Textured Finish
18. Advantages and Disadvantages of
Current Assemblies
Advantages:
Quick Assembly
Budget Friendly Materials
Durable
Disadvantages:
Studs Are Un-insulated Allowing Heat/Cold
Transfer
Can Increase HVAC Loads on the Building
Envelope- Energy Inefficiency
Low Density Polystyrene May Not Resist
Damage Compromising Exterior Finish
Cavity Insulation May Become Saturated
Many Layers of Labor To Install
19. Thermal Bridging-Disadvantage
“These ties should be connected to the steel studs with screws. About two
threads hold this screw in the 16-gauge outside flange of the metal stud.
Thermal bridging at the stud could cause condensation to form at the inside
face of this outside flange in the cold weather months.
A rust or a galvanic cell reaction could develop at the juncture between the
screw and the stud. The connection between the two could eventually
deteriorate and become loose, which means that the masonry tie and the brick
veneer also could become loose, causing cracks in the horizontal (bed) joints of
the brick veneer.
Cracks lead to water penetration through a brick veneer and provide an avenue
for moisture to get inside the building, All associated problems could then be
blamed on the masonry contractor who installed the brick veneer and masonry
ties. However, it is actually a design problem.”
Masonry Construction , Jan, 2003 by Michael Gurevich
20. Only In Cold Climates – Right?
The purpose of
insulation is to
separate
one environment from
the other.
Warm Climates Need Insulation Too!
21. Emerging Sustainable &
Energy Efficient Design
Insulation Needs to Be Applied on the Exterior of Stud
or Frame Wall
What about EIF’s?
22. Emerging Sustainable &
Energy Efficient Design
EIF’s – Right Concept – Wrong Assembly
Why Did It Experience Failures?
Surface could be “Spongy” and Damage Prone
Leading to Water Intrusion and Gypsum Degradation.
Too many site applied layers to be reliable
23. Emerging Sustainable &
Energy Efficient Design
EIF’s – Right Concept – Wrong Assembly
Why Did It Experience Failures?
Surface could be “Spongy” and Damage Prone
Leading to Water Intrusion and Gypsum Degradation.
Too many site applied layers to be reliable
24. Emerging Sustainable &
Energy Efficient Design
The Solution Is to :
Insulate the Exterior of the Frame Wall
Provide Wind and Moisture Barrier
Remove Hygroscopic Materials From the Assembly
Provide a Durable Damage Resistant Surface
That Will Accept Direct Applied Elastomeric,
Faux Stone, Exterior Rated Ceramic Tile or
Brick Veneer
Move the Dew Point Outside the Wall Cavity
25. Emerging Sustainable &
Energy Efficient Design
Concrete Backer Board is a Perfect Solution
This is a new
& emerging
technology
Provides in a
pre-assembled
panel…
Insulation
Vapor and Durable Surface
Wind Barrier
27. Sustainable Energy Efficient
Design – The Time is Now!
Since the energy crisis of the 1970’s, the U.S.
has flirted with energy efficient materials.
When times are flush, energy efficient design
gets forgotten – immediate cost rules!
The use of Concrete Backer Board has developed
over the course of the last 40 years to be a
material of choice in sustainable design.
Emerging technologies and materials will
continue to contribute to not only sustainable but
energy efficient design.