Of all the factors that go into an estimate for building a deck,
labor costs are by far the most difficult to determine. Material
pricing is easy: Count the sticks and bricks that make up the
project and call your suppliers for the figures. Subcontracts are
easy, too: Call your sub and add his price to your bid. Labor
costs, on the other hand, take more effort because there are so
many variables that affect the number of hours a project will take
to complete: weather, site conditions, job size, design complexity,
and crew composition (what I call "the human factor").
With an organized approach, however, and the help of estimating
guides and your own experience, you can set up a system to take
those issues into account and make the estimating process easier.
First you'll need to determine what tasks make up a project and how
you are going to quantify those tasks (for example, by linear feet
of railing or by number of footings). Then, to arrive at your labor
cost, you'll apply a productivity rate that you've calculated for
each task. (You'll also need to establish an hourly labor rate, but
that's beyond the scope of this article.)
1. Identify Specific Tasks and
To price a job, first break it down into distinct tasks. Let's
start with a typical deck job, a simple 10-foot-by-20-foot deck,
approximately 3 feet above grade. Right off, you know you're going
to have at least footings, framing, decking, stairs, and railings
on your list; you may want to get a little more specific, as I have
in the example shown here (Figure 1). You can see that I've also
identified approximate quantities and units of measure for each
task, such as "200 square feet" for installing decking and "3 each"
for installing post bases.
Figure 1. The first step in developing an
estimating system is to make a list of the tasks involved in a
project. Next, the author determines how he wants to measure each
task and what the quantities are.
Once you've broken your project down like this, the next step is to
consult two reliable sources — published guides and your own
records — to determine the man-hours and productivity rates
for each task.
2. Consult Estimating Guides
A number of publishers, including the Craftsman Book Company
(www.craftsman-book.com) and RSMeans (www.rsmeans.com),
release yearly estimating cost books full of cost data for an
assortment of items. In my career as a professional estimator, I've
always recommended using these guides for productivity rates only.
I would not use them for actual cost information, as material
prices can change dramatically from the time the data is gathered
until it's published. Also, hourly labor rates can vary regionally
and should be specific to your business, so figures pulled from a
book are pretty useless. But, for productivity rates, these
guidebooks are an excellent source of reference material, if you
keep a few things in mind.
For one, each book has its own baseline assumption. Some use the
actual time required to perform each task, but others factor in
nonproductive time, such as setup and rollup, coffee breaks, and so
forth. Most guides provide a page or two up front to explain how
their rates are computed.
You also need to pay attention to the complete item description for
each task. If the book lists a productivity rate for framing a
2x10-joist system, for example, does that time include installing
the ledger, the rim board, and the joist hangers? If you can't tell
from the description, you can look to see if related items have
their own listings. If the "2x10-joist system" item doesn't specify
whether joist hangers are included, for instance, but there's a
separate line item nearby for "install 2x10 joist hanger," then
it's probably safe to assume that the time for installing the
hangers isn't included in the system rates.
Be aware, too, that general size and scope of projects vary from
book to book. Productivity rates found in a repair and remodeling
cost book are probably far more realistic and appropriate for a
residential deck contractor than rates pulled from a
commercial-construction guide geared to projects that are typically
While estimating guides can provide data for tasks you've never
done before or never tracked your time on, the figures in the
guides need to be taken with a grain of salt. Even if you
understand the issues listed above and believe you've found an
appropriate book for the type of projects you're estimating, you
should still keep in mind that the productivity rates are typically
compiled from national averages. Several dozen (or even several
hundred) companies may contribute data to the book's publishers,
and that data is then statistically analyzed to arrive at the
printed figures. Consider that your "mileage may vary," and that
you could be estimating less time (a bad thing) or more time (a
good thing, provided it doesn't price you out of a job) than you'll
actually need to complete the project.
3. Track Actual Task Hours
Because of the potential pitfalls of estimating guides, the best
possible labor productivity figures for you and your company will
come from tracking time on your own projects. Whether you're
already running your own company or still working for someone else,
you should keep a pocket notebook to note the time spent on
different tasks. At a minimum, you should also jot down the
• Weather: Was it exceptionally hot or cold, making it
difficult to keep working? Did rain turn the site into a slick mud
• Site conditions: Was the site on a steep slope? Were you
working in a huge backyard with plenty of room for material storage
and a production area, or were you building a 10-foot-by-20-foot
deck in the 12-foot-by-22-foot backyard of a townhouse?
• Material availability: Was all the material you needed on
site or was it stored 300 feet away in the street? Did you have to
cull through piles of bad material to get what you needed?
• Job size: Is this a 100-square-foot deck, or a
2,000-square-foot deck, and how does that affect your
• Design complexity: Was the project a 10-foot-by-20-foot box
or a four-level, curved deck?
• The "human factor": Who performed each task? Did you work
alone, or did you have help? Who was helping, your lead carpenter
or the new guy?
By tracking the time spent on different tasks, you'll begin to see
the effects that these factors have on productivity rates. If you
find that framing a 10-foot-by-20-foot joist system took four hours
on a mild, sunny day, for instance, and it took six hours to
perform the same task on a cold, rainy day, you can quickly see
that the bad weather caused a 50 percent decrease in productivity
(assuming everything else was equal).
You should also track nonproductive time, which will help later
when you're computing hourly rates. As in the sample notebook sheet
(Figure 2), a record of activities includes a lot of information
that can be used to determine productivity rates (among other
Figure 2. Records of actual production time
provide the best data for creating future estimates. Conditions
such as weather, project size, crew composition, and anything else
that might affect productivity should be noted.
In my sample day, 18 man-hours were worked (assuming that the
company does not pay for lunch). Of those 18 hours, one hour was
spent on setup in the morning, one hour on cleanup at the end of
the day, and a half-hour on coffee break. That leaves 15.5
production hours, which is approximately 86 percent of the total
The 200-square-foot joist system in this example took 11.5
man-hours to frame, not including joist hangers. This is a
productivity rate of 0.0575 hours per square foot (11.5 hours
divided by 200 square feet).
However, the joist hangers took 0.75 hour to install. We didn't
identify those as a separate task in our list in Figure 1, so 0.75
hour needs to be added to the 11.5 hours already allotted to
joist-system time; and when the joist-hanger time is accounted for,
the productivity rate becomes 0.0613 hour per square foot (12.25
hours divided by 200 square feet).
Laying out the decking and installing the first 50 square feet took
3.25 hours, which would yield a productivity rate of 0.0650 hours
per square foot of decking (3.25 hours divided by 50 square
If we tracked the next day's activities and found it took 7.5 hours
to install the remaining 150 square feet of decking, the rate on
that day would be 0.0500 hours per square foot (7.5 hours divided
by 150 square feet). This number makes it look like we worked
faster on the second day, until we take into account that the first
day's activity also included the time taken to lay out the decking
pattern and get started.
Combining the two figures tells us that it took 10.75 man-hours to
complete the entire task. Dividing this by the full 200 square feet
of decking gives us a productivity rate of 0.0538 man-hours per
square foot, which is probably a more accurate accounting. It is
also likely what we would have seen if all the layout and
installation had occurred on the same day.
4. Compare Your Data With the Estimating
Once you've compiled some productivity figures from your own
projects, you can compare them with the figures listed in the
estimating guide for the same tasks and get a better feel for how
well the guide applies to your company. Then you can use the book
more comfortably when computing productivity rates for new tasks
that you've never tracked yourself.
Let's say, for example, you need to prepare an estimate for
installing composite decking with concealed fasteners, but you've
never tracked your time for this task before. You know that your
actual time for installing 5/4-inch-by-6-inch cedar decking with
exposed fasteners is approximately 20 percent higher than the time
shown in the estimating guide. Thus, you can likely assume that
applying a similar variance in your current situation will give you
a reasonable estimate. But if you used the book data without having
that point of reference, your actual hours for installing the
decking would likely have exceeded your estimate by 20 percent
— which wouldn't be good for the bottom line.
5. Organize the Data
So, you've been scribbling notes and times in a pocket notebook for
six months, and you've tattered the pages of a few estimating
guides. Now, what do you do with all this information? The answer
depends on how you currently prepare your estimates and how you
plan to prepare them in the future.
If you're still using a yellow pad and a pencil to prepare
estimates, you can compile all the productivity data for your tasks
in a three-ring binder, with tabs for different types of tasks. You
might have a tab for footings and foundations, one for structure,
another for decking, and still others for railings, stairs,
accessories, and so forth. Each tab could then contain a sheet for
each task within that category, on which you've recorded
productivity data for that task from previous jobs. You should
transfer all the pertinent data that you've collected from each
job, so that you can get a good understanding of what caused the
differences in productivity rates for the same task on different
jobs (Figure 3).
Figure 3. While it is possible to track
productivity rates manually in a tabbed notebook, it's faster to
use a spreadsheet program that automatically recalculates the rates
whenever data is added.
While the manual-entry system obviously works, it has its
drawbacks. You have to manually compute all the productivity rates
— highs, lows, and averages — and every time you add
another piece of data, you need to recalculate the rates. Also, the
information is all contained in one book, which creates a major
problem if the book is lost, stolen, or damaged.
By placing the information in a spreadsheet program such as
Microsoft Excel, you alleviate the problems noted above and gain
the ability to build your estimates quickly and accurately. If
you're new to spreadsheets, there are plenty of reference books
available (in bookstores and libraries) to help you learn how to
track data and prepare estimates.
You can also look into canned estimating software. Like estimating
cost books, most estimating software packages come preloaded with
productivity-rate data, and like the books, much of this data can
vary dramatically from your actual figures. By inputting your own
data into the program in place of the preloaded data, however, you
can get all the benefits of the automation and other features of
the software, as well as more accurate estimates.
While estimating labor costs can seem daunting, especially for
those new to the business, with a few simple tracking tools it can
become almost as easy as getting that material quote faxed over
from the lumberyard.
Bob Kovacs is a construction estimator and
manager who frequently consults with contractors on business and