|
COMMON WOOD CEILING ISSUES
Like every construction material, suspended wood ceilings have their
own details to consider. One design compared to another can
have radically different budget impacts.
Main Budget Boosters:
Below are some of the main elements that can raise the budget of
a wood ceiling, impacting either material costs or installation
costs. Each element can have a small or great range of cost impact.
They are listed in order of possible impact:
- Suspension System & Accessibility
- Species and Veneers
- Off-Module Sizes
- Finishes and Stains
- Fire Rating
- Acoustics
- LEED Credits and FSC
- Detailing
- Climatization
|
[also seismic
compliance]
 9Wood
suspended wood ceilings are designed to attach, in a variety of
ways, to commercial T-Bar grid. This means our products are specified
in CSI Division 9, FINISHES, usually 09545 with the ceiling subcontractor
trades in mind. Our Product Suite is designed to permit any experienced
Acoustical Subcontractor familiar with standard T-Bar grid to achieve
successful installs. Using T-Bar to suspend wood ceilings brings
the advantages of suspended ceilings: systems familiarity, low interstitial
suspension costs, ease of installing MEP assemblies, accessibility,
and lower costs.
|
A) Accessibility, such as Lift & Shift solutions, tend
to be least expensive; more elaborate accessibility options, such
as torsion spring and hinged panels, more expensive. Low tech but
elegant solutions, such as Cross Piece Backers with direct screw
to grid satisfy seismic issues and are cost effective. Four factors
should be considered
- Seismic Compliance: In non-seismic zones, Lift &
Shift styles are available without safety wires
- Access Locations: Certain areas are easier to access
than others.
- Access Frequency: Low frequency access can support screw
attachment, frequent access may require threaded bolt & nut
attachment (9Wood T-BoltTM).
- Ceiling Height/Plenum Depth: Some plenums do not have
space for upward panel lift-out.
B) Seismic Zones require designs that attach our wood ceiling
to seismically compliant Grid installations. For some Product Series
(e.g., Wood Tiles) safety tie-offs may be required. Locally stamped
engineering calcs may be required for permit compliance.
 Like all natural materials, variations in color, texture and
grain occur in wood ceilings. Understanding the differences
between species, between grades, between solid and veneer can
influence a wood ceiling budget and design. The complexity of
understanding the cost impact of each design decision, including
LEED credits, can be intimidating.
Several resources are available for further study and resource.
We recommend:
 Architectural
Woodworking Institute Quality Standards Illustrated, 8th
Edition; www.awinet.org.
This is the bible for the architectural-millwork trades, whose
standards can be usefully applied to wood ceilings.
Hardwood
Plywood Handbook, HPVA (Hardwood Plywood & Veneer
Association); www.hpva.org.
This industry association is a great resource for understanding
architectural veneers, species, slicing, veneer matching,
cores, etc.
A) Lumber: The following are typical domestic species.
They are usually specified as "clear"; that is, free
of knots and finger joints:
|
| |
 |
SOLIDS
|
|
VENEERS
|
|
|
| |
 |
|
|
|
|
|
| $$$$ |
|
Cherry |
|
Teak |
|
$$$$ |
| |
|
White Maple |
|
White Birch |
|
|
| |
|
Beech |
|
Cherry |
|
|
| |
|
Red Oak |
|
White Oak |
|
|
| $$$ |
|
White Oak |
|
Walnut |
|
$$$ |
| |
|
Alder |
|
VG Doug Fir |
|
|
| |
|
White Ash |
|
White Ash |
|
|
| |
|
Natural Maple |
|
Red Oak |
|
|
| $$ |
|
Natural Birch |
|
White Maple |
|
$$ |
| |
|
Natural Ash |
|
Beech |
|
|
| |
|
Doug Fir |
|
Khaya African Mahogany |
|
|
| |
|
Hemlock |
|
Natural Birch |
|
|
| $ |
|
Poplar |
|
Natural Ash |
|
$ |
| |
 |
|
|
|
|
|
Of course, dozens of additional domestic and import species
are available.
This price chart is only intended to be a general guide.
Please contact a local rep or the factory for specific pricing.
Factors such as stains may drastically affect pricing. |
B) Veneers: As a company we commonly recommend veneers to architects.
They provide many advantages: cost, color consistency, tight tolerances,
fire rating in the core. In general the more expensive the species,
the more likely a veneer will prove economical. The advantage of using
fire rated particleboard brings another savings to the equation. Two
criteria can mitigate this option:
- the amount of edgebanding required in any given wood ceiling product, or
- the need for extensive field cutting that would expose the core
material and require expensive field edgebanding/endbanding (see
Perimeter Detailing)
C) Veneer Matching
Veneer matching involves 4 elements each with significant cost and
design impacts. (See AWI for detailed reference):
- Veneer Slice (Quarter, Plain or Rotary)
- Leaf Match (Slip, Book or Random)
- Panel Match (Center, Balanced or Running)
- Ceiling Sequence (Custom, End-Match or Random Sequence)
| |
Veneer
Slice |
Leaf
Match |
Panel
Match |
Ceiling Sequence |
| $$$ |
Quarter
Slice
 |
Slip
Match
 |
Center
Match
 |
Custom Sequence
- Blueprint
- Uniform
- Pre-Manufactured
|
| $$ |
Plain
Slice
 |
Book
Match
 |
Balance
Match
 |
End-Match Sequence
- Architectural
- Continuous End
- Panel End
|
| $ |
Rotary
Slice
 |
Random
Match
 |
Running
Match
 |
Random Sequence
|
When seeking a cost-effective veneer specification to a suspended
wood ceiling, three different wood ceiling products need to be considered:
- Wood Tiles: The most common specification for this product
is "Running Bookmatch, Plain Sliced, A grade."
- Perforated Tiles or Acoustic Planks: The most cost-effective
specification for this product is "Running Multi-face, Rotary
Sliced, A or B grade."
- Grilles, Linears, other products: The most cost-effective
specification for this product is "Running Multi-face, Rotary
Sliced, A-B grade."
Traditional millwork specs such as Center Balanced and Endmatching
between Panels is unusual in ceilings because they are not cost
effective.
The economic advantage of specifying standard module sizes is clear.
What is not so clear is the decision tree necessary to determine
what constitutes the standard module in any given application. In
general, industry-wide module sizes follow one of three raw material
selections:
- Veneers (standard raw material module is a 4'x8' sheet
good)
e.g., Specifying a 24" x 24" panel produces a good yield,
a 30" x 30" panel produces a poor yield.
- Hardwood (standard modules 3/4" Net thickness
by random width)
e.g., Specifying a 3/4" x 2-1/4" member produces
a good yield, 1" thick x 2-1/4 " wide produces a poor yield.
- Softwood (nominal dimensional sizes; that is a 2"x4"
nets out at 1-1/2 " x 2-1/2 ")
e.g., Specifying a 3/4" x 2-1/4" member produces
a good yield, a 1" x 1-3/4" produces a poor yield.
Of course, off-module sizes are available. For extra information and
cost impacts of various options, please contact 9Wood Tech Support
or your local architectural rep.
A) Clear Finishes: Factory finishing is usually selected
for high-quality work where superior appearance and performance
of the finish is desired. The purpose of finishing woodwork is twofold.
First, the finish is used traditionally as a means to enhance or
alter the natural beauty of the wood. Second, the finish protects
the wood from damage by moisture, contaminants, and handling.
The most commonly used finish we offer is a clear catalyzed lacquer.
Because ceilings do not require a durable finish, this is our recommended
finish. It is an excellent choice and comes with brilliant finish
clarity. The cost of the finish system varies, with the higher performing
finishes usually costing more. Unnecessary cost can be added to
a ceiling project through over-specification.
| Finish System |
Standard
Lacquer |
Catalyzed
Lacquer
(our most common) |
Water Acrylic Lacquer
(Low VOC LEED EQ 4.2) |
Conversion
Varnish |
| General Durability |
Fair |
Average |
Fair |
Good |
| Finish Clarity |
Excellent |
Excellent |
Good |
Average |
| Finish Flexibility |
Poor |
Average |
Average |
Good |
| Stain Resistance |
Good |
Excellent |
Good |
Excellent |
| Heat Resistance |
Poor |
Excellent |
Poor |
Excellent |
| Moisture Resistance |
Average |
Good |
Average |
Good |
| Solvent Resistance |
Poor |
Good |
Poor |
Excellent |
B) Stains: Stains beautify wood, but can also be a tricky
element in specifying a wood ceiling because they are relatively
expensive, frequently doubling or tripling the finish costs associated
with manufacturing a wood ceiling and because color matching is
often subjective. Often a custom match is required. The key to a
good outcome is providing all trades with sufficient color control
samples, typically 3 different samples showing acceptable color
variation. AWI is a good resource for explanation of stain processes,
including tinted lacquers, dye stains and wiping stains.
Most wood ceilings are specified Class 1(A), which actually exceeds
the standard code requirements (see relevant codes, Section 8 Interiors).
The Flame Spread Index (now called the Surface Burning Characteristics
Rating) fixed Concrete-board at 0 and Red Oak at 100. This is an
arbitrary scale, not a rate at which flame actually spreads along
material's surface.
The Steiner Tunnel Test is used to calibrate a material's Flame
Spread Index and is called the "Method of Test of Surface Burning
Characteristics of Building Materials" (NFPA No. 255, ASTM E
84, UL No. 723). It is commonly known as the Steiner Tunnel Test.
A 2' x 20' sample of the material to be tested is placed along the
inside top of a long metal tank. A gas flame is applied at one end
and a regulated constant draft is directed through the tunnel from
the flame end. The progress of the flame front along the sample
is observed through side windows and timed to fix the Flame Spread
Index (FSI). Smoke is also collected to fix the Smoke Developed
Index (SDI)
 |
| Ed points out the results of the Steiner Tunnel
Test on some common materials. |
A) Lumber is naturally Class 3(C) with a flame spread of
around 100 (though some species are considerably higher (e.g., Poplar
FS=185), others actually achieve a Class 1(A); (e.g., Ipe FS=10);
still others a Class 2(B); [e.g., Hemlock (FS 72)]. To reduce the
flame spread to less than 26, topical coatings are applied to the raw
wood. 9Wood uses a product called Flame Stop II™, a clear pyrolytic
surfactant. For most purposes, the majority of wood finishes, veneers,
or lumber require some type of treatment to achieve a Class 1(A)
Rating.
B) Veneered products are generally 130-160 flame spread.
No clear topical coating that we know of can reduce an hardwood
plywood down to a Class 1(A). To achieve Class 1(A) veneered products
we utilize a Class 1(A) particleboard core substrate with wood veneers.
The Section 8 Interiors code stipulates that if the veneer face
is less than 1/28" (having surface burning characteristics
no greater than paper), the substrate confers the fire rating.
9Wood utilizes Duraflake® by Flakeboard of Canada Fire-Rated particleboard. Several advantages of veneers
on FR cores exist, including grain and color consistency, tolerance
control, and often cost efficiencies. For LEED Credit MR-2 Recycled
Content contribution, we also use Medite FR (FR MDF), though the
base cost is higher.
The 9Wood Product Suite offers a variety of acoustic performances:
1) Absorptive, 2) Reflective, or 3) Conductive. In blending science
and art for room acoustics, nothing compares with the expert advice
of an acoustical engineer. Our goal is to provide wood surfaces that
bridge architect and consultant.
Consistent with good acoustics is employing the ceiling surface
to influence the sound performance of a space. The wrong material,
such as metal, can impart a "tinny" or "metallic" signature to the
sound. Plastic and fiberglass tend to be "drummy". On the other
hand, wood is acoustically warm and organic—one reason acoustic
instruments are normally made from wood.1 |
Wood surfaces are naturally Sound Reflective with an NRC
(Noise Reduction Coefficient) of .05-.15.
Reflection, where sound bounces off a flat surface back
into the room, can be used strategically in room acoustics where
bright, lively sound is desired, or where other wall or floor absorption
is sufficient.
Diffusion, the scattering of reflective sound, can be achieved
by means of a Wood Wave Tile (a curved surface) or scattered by
means of irregular surfaces like wood grilles or cubes. |
|
Broad-band and narrower-range Sound Absorption (NRCs of
.65-.90) can be economically achieved by means of different openings
in the wood ceiling; perforations, reveals, grooves, or openings
allow for a percentage of sound energy to pass through the wood
ceiling into the plenum and be absorbed by fiberglass acoustic backing
material. In general, the thicker the fiberglass backing (3-6# density,
1" to 6" thick) the greater absorption will be achieved,
especially at lower (bass) frequencies.
Our Perforated Wood Tiles and Acoustic Plank products create Tuned
Resonant Sound Absorbers which means they provide peak absorption
at certain, typically mid-range frequencies.
 |
Frequency graph of 3100 Acoustic Plank -
'A' Mount Test |
In general, the more holes required in a perforated wood tile,
the higher the price. On the other hand, larger diameters holes
(up to 12mm (1/2")) do not add cost to a perforated tile if
the number of holes remains the same.
9Wood's Acoustic Plank products achieve an NRC of .90 with fiberglass
backing. Acoustic Test results for a number of 9Wood products can be found on our "Acoustic Test Results" page.
Standard % Opening Ranges:
Wood Grilles (S1000): 50-70%
Linear Wood (S2000): 13-25%
Acoustic Wood (S3000): 15%
Perfed Wood Tiles (S5000): 5-22%
Finally, Conduction refers to sound passing entirely through
the wood surface and out of the room entirely. It is not absorbed;
it is transferred into the plenum space.
 Learn more about LEED Credits & FSC in 9Wood products.
Several opportunities exist for suspended wood ceilings to earn LEED (Leadership
on Energy and Environmental Design) credits. LEED provides a definitive
standard for what constitutes a "green building". Created
by the U.S. Green Building Council, the LEED Green Building Rating
System™ evaluates a building’s environmental performance
from a "whole building" perspective over its entire life
cycle.
A choice of 69 credits is available to the design team. They serve
as voluntary, market-driven building criteria, each representing
effective practices and emerging concepts in energy and environmental
design. In the words of the US Green Building Council, "LEED
was created to define what is a 'green building' by establishing
a common standard of measurement, promote integrated, whole-building
design practices, recognize environmental leadership in the building
industry, stimulate green competition, raise consumer awareness
of green building benefits and transform the building market."
Hard and fast rules are not easy to establish, but in general, the
cost impact range for each option is as follows:
| LEED |
|
LEED Element |
|
Points Opportunity |
|
Final Cost Impact |
| MR 3.1 / 3.2 |
|
Materials Reuse: 5% / 10% |
|
1-2 points |
|
+30-40% |
| MR 4.1 / 4.2 |
|
Recycled Content: 10% / 20% (post-consumer + 1/2 pre-consumer) |
|
1-2 points |
|
+30-40% |
| MR 5.1 / 5.2 |
|
Regional Materials: 10% / 20% Extracted, Processed and Manufactured Regionally |
|
1-2 points |
|
-5%-0% |
| MR 6 |
|
Rapidly Renewable Materials |
|
1 point |
|
+10-15% |
| MR 7 |
|
FSC Certified Wood |
|
1 point |
|
+5-10% |
| EQ 4.4 |
|
Low-Emitting Materials: Composite Wood and Agrifiber Products |
|
1 points |
|
+5-10% |
|
MR-7: FSC — the "Well Managed Forest" Credit
 The
LEED program gives "green" credits when Forest Stewardship
Council certified wood is used to fabricate your wood ceiling. LEED
gives this credit because FSC certification guarantees that the
lumber used in your wood ceiling comes from wood harvested responsibly
from an eco-friendly commercial forest. |
How does this work? It involves a pedigree program, beginning with
a certified forest and traveling to the final wood product. The
international Forest Stewardship Council oversees local organizations
that certify well-managed forests and their wood products. The operative
word is well-managed when talking technically about
certified wood. 9Wood carries a Chain-of-Custody FSC certified manufacturer
identifier, SCS-COC-0667. This means that we have the privilege
of carrying the FSC logo through our quarantined and audited fabrication
processes to the end project for your LEED credit.
FSC History
The environmental movement along with a remarkable number of commercial
timber concerns birthed the independent, third party forest certification
program called the Forest Stewardship Council. The idea was to create
market demand by guaranteeing consumers that their purchases of wood
products truly came from well-managed forests. Market demand for
"green" lumber, not government intervention or industry
self-watch groups, would be the ultimate safety net for the world’s
forests. The worldwide Forest Stewardship Council was created in
1993 along with the FSC eco-label imprimatur.
Three global criteria were developed to evaluate a well-managed forest:
- Healthy maintenance of the total forest ecosystem
- Production of wood on a sustained, renewable basis
- A positive social and economic impact on surrounding communities
Learn more about LEED Credits & FSC in 9Wood products.
A) Perimeter Details
Perimeter conditions are often overlooked when specifying a suspended
wood ceiling, despite having a substantial impact on cost and design
details. Four suspended wood ceiling perimeters are used—Ledgers,
Reveals, Floating, or Custom Perimeters:
- Floating (3-6" or greater) permit factory cutting
based on approved shop drawings and can be quite cost effective.
- Ledgers using wall angle, shadow molding, or a wood ledger
are the most cost effective perimeter detail because a ledger
covers over field cut edges, making the installation cost effective
and detailing attractive. This is an especially useful detail
when specifying a veneered product, which otherwise might require
costly endbanding.
- Reveals (1/2-1") often require precision field cutting
or a high degree of As-Built dimension coordination between 9Wood
and the field. This can be expensive.
- Custom (see Series 9000) requiring custom or non-perforated
borders at the perimeter become a significant design decision.
9Wood has three methods for achieving custom or non-perfed borders
at the perimeter:
- Plexiglas jigs for field perfing or routing
- Factory perfing or routing to approved shop drawings
- Factory perfing or routing to As-Built field dimensions
B) Penetrations details
The primary issue involving MEP (Mechanical, Electrical, Plumbing)
penetrations in the ceiling surface are the following:
- Will penetrations use escutcheon plates or flanges to cover
the cut-out?
- Can fixture cutouts (sprinklers typically excluded) be factory
located based on approved shop drawings, general "centering"
rules, or do they require coordination with an As-Built condition?
Higher As-Built coordination requires higher cost.
- Fixtures must be independently suspended from the structure
and not from the wood ceilings.
- Linear diffusers require special consideration to accommodate
the interaction with the T-Bar grid lay-out. Send the diffuser
cut-sheets to 9Wood for assistance in detailing the lay-out and
suspension.
C) Small reveals
The "rule of 8" applies to all reveal tolerances: 1. Wood
tolerance, 2. Product tolerance, 3. T-Grid Hardware tolerance, 4.
Installation Tolerance x 2. The smaller the reveal, the tighter the
tolerances required, increasing cost and the likelihood that the
reveal will open or close displeasingly following installation.
And, of course, all wood products are subject to expansion and contraction.
Reveals of less than 1/4" are unrealistic considering
the reality of T-Bar grid installation. We generally recommend the
following reveals:
- Wood Tiles and Perforated Wood Tiles: 3/8" or larger
- Grilles or Linear Panels: 3/4"
D) Sample Shop Drawings: See example (PDF, 1.2mb)
Temperature & humidity changes will cause moisture to move in
and out of all wood products. It is important to specify and insure
that controlled environments are utilized during storage, installation
and maintenance. Warpage and reveal problems can result if climatization
is not controlled.
Quoting from the Architectural Woodworking Institute:
Wood is a hygroscopic material, and under normal use all wood
products contain some moisture. Wood readily exchanges this molecular
moisture with the water vapor in the surrounding atmosphere according
to the existing relative humidity. In high humidity, wood picks
up moisture and swells; in low humidity wood releases moisture and
shrinks. As normal minor fluctuations in humidity occur, the resulting
dimensional response in properly designed construction will be insignificant.
To avoid problems, it is recommended that relative humidity be maintained
within the range of 25-55%. Uncontrolled extremes—below 20%
or above 80% relative humidity—can likely [sic] cause problems.
9Wood, Inc. offers the building owner a standard one-year warranty
as a guarantee of good material and workmanship. The warranty is
limited, with the standard boilerplate disclaimers, including fitness
for use and merchantability.
 |
| "Bill, I just don't get the concept...
a bench on the ceiling?" |
See the Story of 9Wood (with a brief history
of commercial wood ceilings). And yes, it began with a bench on the
ceiling.
|
| |
|
|
| |
|
|
| |
|
|
|
