HOW TO ESTIMATE THE COST OF T-BAR
ACOUSTICAL CEILINGS
MICHAEL HILL
DATE WRITTEN: MAY OF 2007
The author is Michael Hill, Estimator with Kaiser Foundation
Hospitals, National Facilities Services Cost Engineering
Group. Michael has been a member of ASPE since 2006.
Michael has more than twenty-five years experience in the
construction and remodeling of hospitals and office buildings.
Experienced in all phases of construction including design,
computer aided drafting (CAD), space design, estimating,
scheduling, presentations, project management, supervision
and project inspections. Michael has worked in the
construction business with his father, a general contractor, and
then for Kaiser Foundation Hospitals as a journeyman
carpenter in 1980. Since then he has been in engineering,
worked as a CAD (computer aided drafting) designer,
designed databases for work order and equipment tracking, a
project superintendent, a project manager, a space designer
and an estimator. The Cost Engineering Group Michael works
with oversees the maintenance and renovation estimating for
eleven of the Kaiser Permanente Medical Centers.
TABLE OF CONTENTS
INTRODUCTION
• Main CSI Division
• Specific Subdivision/ Specification Section
• Brief Description
TYPES AND METHODS OF MEASUREMENT
• Material take-off review
FACTORS THAT AFFECT TAKE-OFF, PRICING, ETC
• Small versus large quantities
• Geographic location
OVERVIEW OF LABOR, EQUIPMENT, MATERIAL, AND
INDIRECT COSTS
• Sample of production rates
SPECIAL RISK CONSIDERATION
RATIOS AND ANALYSIS – TOOLS TO TEST FINAL BID
MISCELLANEOUS PERTINENT INFORMATION
• Sample ceiling specifications
CONCLUSION
DETAIL SHEETS
• Sample sketch
• Sample take-off sheet
• Sample pricing
INTRODUCTION
This paper will address the materials and methods used in cost
estimating for acoustical suspension ceilings with acoustic
ceiling tiles (commonly called “T-bar” because of the T shaped
supports). The T-bar acoustical ceiling system is an extremely
versatile product. Buildings that commonly use T-bar
acoustical ceilings are commercial buildings, hospital buildings,
schools, and residential modular homes. T-bar acoustical
ceiling systems can be installed in all types of structures made
from wood, metal, steel and concrete.
Main CSI Division – Division Nine, (9) “Finishes”
Subdivision – Specification Section 09100 Metal Support
Assemblies
09130 “Acoustical Suspension”
Specification Section 09500 “Ceilings”
09510 “Acoustical Ceiling”
Brief Description
The T-bar acoustical ceiling system provides the following
benefits; sound attenuation, access to utilities above,
architectural design enhancement, ease of maintenance, ease
of replacement of tiles, suspension of lighting and room
utilities.
The T-bar grid system consists of main runners, cross runners,
wall angles, support wires and struts. There are many methods
used to install the T-bar grid system, depending on the system
and design requirements. For example support wires are
dropped through the pan-deck, shot in the ceiling using power
actuated fasteners or anchored using drilled expansion anchors
(see Details 3 & 5). The sections of anchored wires are then
tied to the T-bar (see Detail 2). Additional grid wires are also
installed to support other trade’s ceiling installed items. For
example light fixtures and HVAC (heating ventilation & air
conditioning) registers which are also laid into the finished grid
system.
Acoustic tiles are then placed into the grid along with the other
trades items to finish the ceiling work. Many tiles will need to
be cut to provide openings needed for fire alarm, fire
sprinklers, special lighting cans and security components. The
support elements of these components are usually provided by
the other trades and are not figured in the estimate.
Acoustic tile sizes and material vary greatly depending on
usage. Sizes include: 24” x 24” panels and 48” x 24” panels.
There are fire rated tiles, fiberglass, plastic coated, aluminum
and material fiber tiles in many styles and colors. There are
also tin tiles with hundreds of patterns and colors. T-bar grid
also comes in a variety of materials and colors. This paper will
only review the heavy-duty T-bar acoustical ceiling system.
Materials required to build a T-bar ceiling include:
1)
Hanging wires
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Estimating Today | 17
2)
3)
4)
5)
6)
Seismic posts
Wall angle
Main runners
Cross runners
Acoustic drop in panels
TYPES AND METHODS OF MEASUREMENT
Methods used to create a material take-off used by T-bar
acoustical ceiling estimators, are accomplished by using the
following units of measurement: square feet, item count and
linear feet. Direction of tiles needs to be reviewed. The layout
of fire sprinklers, HVAC registers, lighting and fire alarm work
all needs to be reviewed. Often the T-bar ceiling subcontractor
is asked to supply and install hanger wires for the other trades.
Information needed to estimate quantity of support wire
counts, needs to include HVAC registers and light fixtures.
Material take-off review
The material take-off is done by first measuring the room for
width and length. Material can be figured using a spreadsheet
with calculations added (see Sample Material Take-off).
AREA
PANEL
MR
CR 4’
CR 2’
WA
Area is calculated – width of room multiplied
by the length of room.
Panel count is calculated – Divide area by
eight square feet for 2’X4’ ceiling panels
(subtract light and HVAC register square
footage).
Main runners are calculated in linear feet –
Area divided by four.
Four foot cross runners are calculated – Main
runners multiplied by two.
Two foot cross runners are calculated – 2’x2’
lights and HVAC registers multiplied by two.
Wall angle length is calculated – Width of
room plus length of room multiplied by two.
Note: The wall angle length may vary depending on the
amount of cuts in a room, so a linear foot take-off may be
required here.
2’ STRUT
4’ STRUT
V WIRE
P WIRE
Two foot strut calculation – Width of room
divided by two.
Four foot strut calculation – Width of room
divided by two.
V wire (vertical) is calculated - Main runner
total length divided by four.
P wire (perimeter) is calculated – Width of
room divided by two plus length of room
divided by four multiplied by two.
conditioning) registers are counted from the
reflected ceiling plan and multiplied by four
square feet usually. There are many styles of
registers, including 4’ slot registers, that will
needed to be reviewed so your take-off
reflects the required wires and runners.
Additional materials that need to be figured for the estimate
includes the wall angle fasteners, pop and grid fasteners. These
items are calculated on the Pricing sheet along with labor,
taxes and mark-up.
•
Wall angle fasteners are calculated – One for each wall
angle.
•
Pop and grid fasteners are calculated – Wall angles divided
by five.
FACTORS THAT MAY AFFECT TAKE-OFF, PRICING,
ETC.
Small versus large quantities of material can affect the overall
productivity on projects. Factors that may affect productivity
include manpower, material, jobsite stocking and equipment.
Shop drawings, engineering and sub consultants may be
required on larger projects.
Large projects can increase installation efficiency by assigning
labor to specific tasks and for use of full days to complete
tasks. Material can be stock piled on larger projects where
there is room to do so. If man lift equipment is required, larger
projects may increase installation productivity. Some buildings
have continuous T-bar grid systems with walls that abut the
ceiling. These walls will not have edge support angles except at
firewalls or exterior walls, where the wall runs’ above the
ceiling.
On small projects the material quantity minimum purchase
may exceed the actual quantity needed for installation. Smaller
rooms use more wall angles per square foot. The estimator may
need to include a full days pay for a partial days work.
Geographic location does affect the labor and material costs of
any project. This needs to be reviewed prior to finalizing the
estimate. Geographic location is affected mostly on small
projects. Travel time may also need to be included due to
distance between small projects. Local labor availability, skill
levels & cost per hour are also factored into costs. Material
and Labor rates are always factored into the estimate and
should reflect local costs. Uniform Building Code and state
building code standards are to be reviewed, as some states may
have other requirements.
Example: (W/2+L/4)x2.
S POST
S WIRE S
LIGHTS 2X4
LIGHTS 2X2
HVAC
S Posts (seismic) are calculated – Area
divided by 96.
wire (seismic) is calculated – Total S posts
multiplied by five.
Lights are counted from the reflected ceiling
plan and multiplied by eight square feet.
Lights are counted from the reflected ceiling
plan and multiplied by four square feet.
HVAC (heating ventilation & air
18 | Estimating Today
Commonly, the grid system is installed in an enclosed envelope
of the building so weather is not a large consideration.
However, support wires are typically installed in a new building
after structural steel and pan deck are in place. In cold or
windy weather this could affect the installation efficiency.
OVERVIEW OF LABOR, EQUIPMENT, MATERIAL AND
INDIRECT COSTS
The T-bar acoustical ceiling systems are available in many
styles many, which require special installation procedures and
production costs. This paper will only review the heavy-duty Tbar acoustical ceiling system.
A review of the construction documents will reveal conditions
that will determine the production costs, type of material,
equipment and any indirect costs. A hospital will require
additional labor due to the need for drilled inserts for the
seismic wires. Also, a hospital demands additional wire
supports due to the additional HVAC ducts in the plenum
above. For standard commercial applications, powder-actuated
fasteners are used.
Sample of production rates
The information below is used in the example-pricing sheet
(see page 26)
•
•
•
•
•
One man can install about 300 wires a day, using a power
actuated fastener or drill. One man can install about 60
wires a day using drilled in expansion anchors. Wires will be
about 25% of the overall area. (100 square feet has
approximately 25 wires).
Grid installation rate is about 600 square feet per day, per
man.
One man can install approximately 800 square feet of drop
in tile per day.
One man can install approximately 25 seismic posts per
day. One seismic post is required every 96 square feet of area.
Wall angle installation is approximately 300 linear feet per
day. Wall angle is approximately 25% of the area. (1,000
square feet has approximately 250 linear feet of wall
angle).
installations and ceiling panel installations, which means labor
will need to be on hand and ready when other trades are
complete (labor will have to come back twice to complete the
ceiling work). Going on a job walk of the site to review
conditions can eliminate many risks.
RATIOS AND ANALYSIS – TOOLS TO TEST FINAL BID
Reviews of past projects of a similar type can be gathered.
Historical data is used for ratios and reviews. This is
particularity useful when figuring for man-hours and material.
Projects may vary greatly depending on scope. Maintaining
historical data from previous projects and post construction
evaluations will support new estimates with true baseline
information. Many percentages will hold true and assist in the
analysis of the estimate.
Post construction evaluations are preformed after your project
is completed. This evaluation is a useful tool in looking into
costs incurred, processes, products, services and review of any
errors or changes from your final estimate. This process allows
you to learn the best practices to estimate future projects. You
will need to evaluate your final estimate versus actual costs,
general requirements, direct costs, schedule impacts and
change orders that affected the ceiling work. In a post
construction evaluation you can review your production rates
and update them as needed.
Many computer programs can utilize this historical data to
graph a project, creating a visual representation. The following
Figures No. 1 and No. 2 show the sample pricing sheet (see
page 26) percentages in two different formats. The sample
displays the ratios of tasks needed to complete the estimate.
Journeyman Carpenter cost in the San Francisco Bay Area
including burden is, approximately $620.00 per day*.
SPECIAL RISK CONSIDERATION
Risk considerations include:
Schedule of work.
• Phasing of the project.
• Relationships with bidding general contractors and access
to project location.
Types of ceiling installations.
• Deck structure & material.
• Wall type.
• Anchor type.
• Grid type.
• Ceiling tile style.
All the items above factor into the final costs and must be
reviewed prior to completing the estimate. Complex ceiling
designs will also need to be reflected in the estimate such as,
curves, soffits, special curtain and lighting. Other trade
commodities and their schedule can affect the estimate,
including light fixture wires and installation of HVAC register
wires. When reviewing the contract documents the reflective
ceiling plan is the main drawing for review, it is also prudent to
review the plumbing, HVAC and electrical drawings prior to
completion of your take-off. A review of the ceiling
specifications of a project is also required as they may explain
items not shown on the plans (see Sample Specification).
Schedules may indicate large periods between support wire
Figure No. 1
Figure No. 2
Estimating Today | 19
MISCELLANEOUS PERTINENT INFORMATION
This paper is a review of how to estimate a T-bar acoustical
ceiling system. The larger ceiling contractors utilize take-off
digitizers and estimating programs. “On Screen” is the take off
program of choice and “Quick Bid” is an estimating program
that is very popular. The choice of which program or take-off
method used depends on your company and specific type of
work. Your company and labor resources will determine which
method works best to meet the project needs.
prevent lateral spreading. A metal strut or a 16-gauge
wire with a positive mechanical connection to the runner
may be used (see Detail 1). Where the perpendicular
distance from the wall to the first parallel runner is 12”
or less, this interlock is not required.
1.6
SAMPLE CEILING SPECIFICATIONS
Ceiling Notes For Metal Suspension System For Lay In Panel
Ceilings:
Provide bracing assemblies consisting of a compression
strut and four (4) 12 gauge splayed bracing wires
oriented 90 degrees from each other at the following
spacing (see Detail 1).
1.
2.
Provide metal suspension system for lay in panel ceilings as
follows:
General: Requirements for design and installation of
suspended acoustical ceiling systems are contained in the
Uniform Building Code, and in the building code standards of
the local state that work is being completed.
4.
Place bracing assemblies at a spacing not more
than 8 feet 12 feet on center.
Provide bracing assemblies at locations not more
than one-half (1/2) the spacing given in 1 (1.6) 1
above from each perimeter wall and at the edge of
vertical ceiling offsets.
The slope of these wires shall not exceed 45
degrees from the plane of the ceiling and shall be
taut. Splices in bracing wires are not to be
permitted without special approval.
Suspended acoustical ceiling systems with a ceiling
area of 144 square feet or less, and fire rated
suspended acoustical ceiling systems with a ceiling
area of 96 square feet or less, surrounded by walls
which connect directly to the structure above, do
not require bracing assemblies when attached to
two adjacent walls.
1.0
Ceiling Notes: The following notes are examples of
specifications for ceiling systems whose total weight,
including air conditioning grills and light fixtures, does
not exceed four pounds per square foot. Heavier systems
and those supporting lateral loads from partitions will
require special design details.
1.1
12 gauge (minimum) hanger wires may be used for up to
and including 4’ - 0” x 4’ -0” grid and shall be attached to
main runners (see Detail 2).
1.2
Provide 12 gauge hanger wires at the ends of all main
and cross runners within eight inches (8”) of the support
or within one-fourth (1/4) of the length of the end tee,
whichever is least, for the perimeter of the ceiling area.
Fasten hanger wires with not less than three (3) tight
turns (see Detail 5). Fasten bracing wires with four (4)
tight turns (see Detail 3). Make all tight turns within a
distance of 1-1/2 inches. Hanger or bracing wire anchors
to the structure should be installed in such a manner
that the direction of the wire aligns as closely as possible
with the direction of the forces acting on the wire (see
Details 3 & 5).
In some cases end connections for runners, which are
designed and detailed to resist the applied vertical and
horizontal forces may be used in lieu of the 12 gauge
hanger wires, subject to review and approval.
Note: Wire turns made by machine where both strands
have been deformed or bent in wrapping can waive the
1-1/2” requirement, but the number of turns should be
maintained, and as tight as possible.
1.3
Provide trapeze or other supplementary support
members at obstructions to typical hanger spacing.
Provide additional hangers, struts, or braces as required
at all ceiling breaks, soffits or discontinuous areas.
Hanger wires that are more than 1 in 6 out of plumb are
to have counter-sloping wires. Obstructions such as large
ductwork will require extra wires and will need to be
added to the take-off.
1.4
Ceiling grid members may be attached to not more than
2 adjacent walls run diagonally to ceiling grid members
shall be at least 1/2 inch free of other walls. If walls run
diagonally to ceiling grid system runners, one end of
main and cross runners should be free, and a minimum
of 1/2 inch clear of wall (see Detail 2).
1.5
At the perimeter of the ceiling area where main or cross
runners are not connected to the adjacent wall. Provide
interconnection between the runners at the free end to
20 | Estimating Today
1.7
1.8
Separate all ceiling hanging and bracing wires at least six
inches (6”) from all un-braced ducts, pipes, conduits,
etc. It is acceptable to attach lightweight items, such as
single electrical conduit, not exceeding 3/4” nominal
diameter, to hanger wires.
1.9
When drill-in concrete anchors or shot-in anchors are
used in reinforced concrete for hanger wires, 1 out of 10
must be field tested for 200 pounds of tension, when
drilled-in anchors are used for bracing wires, 1 out of 2
must be field tested to 440 pounds in tension. Shot-in
anchors are not permitted for bracing wires. If any shotin or drilled-in anchors fail, a review of local building
codes will be required.
Note: Drilled-in or shot-in anchors will require special
approval when used in pre-stressed concrete.
1.10 Attach all light fixtures and ceiling mounted air
terminals or service, to the ceiling grid runners to resist a
horizontal force equal to the weight of the fixtures.
Screws or approved fastener are required.
1.11 Flush or recessed light fixtures and air terminals or
services weighing 56 pounds or more must be supported
directly on the runners of a heavy duty grid system but,
in addition, they must have a minimum of two 12 gauge
slack safety wires attached to the fixture at diagonal
corners and anchored to the structure above. All flush or
recessed light fixtures and air terminals or services
weighing 56 pounds or more must be independently
supported by not less than four (4) taut 12 gauge wires
each attached to the fixture and anchored to the
structure above regardless of the type of ceiling grid
system used.
SUSPENDED CEILING BRACING ASSEMBLY
SCALE: NOT TO SCALE
DETAIL 1
The four (4) taut 12 gauge wires including their
attachment to the structure above must be capable of
supporting four (4) times the weight of the unit.
1.12 Support surface mounted light fixtures by at least two
positive devices which surround the ceiling runner and
which are each supported from the structure above by a
12-gauge wire. Spring clips or clamps that connect only
to the runner are not acceptable.
Provide additional supports when light fixtures are 8
feet or longer.
1.13 Support pendant mounted light fixtures directly from the
structure above with hanger wires or cables passing
through each pendant hanger and capable of supporting
four (4) times the weight of the fixture. A bracing
assembly is required where the pendant hanger
penetrates the ceiling. Special details are required to
attach the pendant hanger to the bracing assembly to
transmit horizontal forces.
1.14 Classification of ceiling grid (Manufacturer)
Classification of ceiling grid is heavy duty for this
paper.
Manufacturer’s catalog number - main runner heavy duty.
Manufacturer’s catalog number - cross runner heavy duty.
Manufacturer’s catalog number of detail for runner
splice (see Detail 6).
CONCLUSION
In summary, this paper explains how to estimate the cost of Tbar acoustical ceilings. There are many factors that affect your
take-off. For example, the project size, geographic locations
and special risk considerations. In addition, a review of labor,
equipment, material, and indirect costs are needed to complete
the T-bar acoustical ceiling estimate. The types and methods of
measurement used for take-offs are item count, square footage
and linear footage. Lastly, an estimator should incorporate
historical ratios and analysis tools to test final bid.
HANGER WIRE CONNECTION TO GRID
SCALE: NOT TO SCALE
DETAIL 2
Estimating Today | 21
SIESMIC (SPLAY) WIRE ATTACHMENT
SCALE: NOT TO SCALE
DETAIL 3
RUNNER SPLICE
SCALE: NOT TO SCALE
DETAIL 6
HANGER WIRE SPLICE
SCALE: NOT TO SCALE
DETAIL 4
VERTICAL WIRE ATTACHMENT
SCALE: NOT TO SCALE
DETAIL 5
22 | Estimating Today
SAMPLE SKETCH
SAMPLE TAKE-OFF AND PRICING SHEETS
(See material take-off review for details)
**
Carpenter Northern California trade union agreement with AGC dated January 2007.
Estimating Today | 23