When I learned to estimate we had
printed estimate sheets which had all the fittings listed in a column
and I would go over the drawings making little marks, in groups of
five, beside each fitting. Then I would count up all the pieces of
pipe. Hub pipe has to be counted in 10', 5', and 30” lengths –
single hubs and double hubs. Next I added up all of the marks,
extended the fitting and pipe prices to find my material cost.
After that came hangers, pounds of
lead, rolls of solder, tanks of gas, etc. until all the material was
accounted for. Labor required a little experience as to how long
things take men to do – everything from digging trenches to pouring
joints to setting fixtures. But everything was done on paper and
calculations were done on an old adding machine. We stapled the tape
from the adding machine to the quote when we were done in case we
needed to go back and check something.
Today everything is electronics and
spread sheets. That's not a bad thing. We do take-offs from .pdf
drawings, enter quantities into spread sheets and automate as much as
we can. On a spread sheet you can include labor in a column right
beside material cost and Excel will calculate both when you enter a
quantity of fittings or pipe. I even have equations that pull the
pipe and fitting quantities from one sheet and calculate the hangers
and no-hub couplings I need on another sheet. Same with copper pipe
and fittings extending to flux, solder, and mapp gas.
Saving steps saves time and increases
accuracy. If I'm tallying pipe on one sheet and then jumping to
another sheet to tally couplings and another to tally hangers, I
could get in a hurry and miss something. The spread sheet does it
automatically and doesn't miss a thing – as long as your macros are
set up right. I add a fitting and it adds solder and flux and sand
cloth and the labor it takes to make the joint! Everything is fast,
efficient, and accurate.
Now as we move into Revit we have tools
to cut those steps even more. In Revit we can throw out the process
of counting all together. Revit schedules are basic spread sheets.
You probably already use them as schedules on your drawings –
listing the pipe, fittings, equipment and fixtures. You may even go
to your Revit schedules to get your take-off numbers to plug into
your estimating spread sheet. But why are you using two spread
sheets? Remember, schedules in Revit are just spread sheets you fill
with data from families.
Revit schedules have all the basic
functions of Excel spread sheets. You can export them as spread
sheets. You can print them as spread sheets. And you can apply
calculations and formatting JUST LIKE EXCEL SPREAD SHEETS. Now let
that sink in.... I can set up my schedule to bring in material and
quantities. I can add calcs to the schedule to use those quantities
in equations. Now, if my families and calcs are right, when I draw a
copper tee Revit adds solder, flux, sand cloth, and labor to the
schedule in correct quantities. Revit does my material takeoff as I
design and if I delete that tee, Revit adjusts everything!
You can take that to the logical
conclusion. If I set my “Estimate Schedule” up like my estimate
spreadsheet – with labor burden, overhead, profit, etc – the
estimate does itself as I design. When the model is complete, the
estimate is complete, and if I make changes – the estimate updates.
If I'm given a finished model all I do is create my estimate schedule
and I'm done. The estimate fills itself in! If I make changes during
coordination, I can compare the new estimate against the old and know
exactly what dollar figure that change represents. Instantly!
Disclaimer. As I've said over and over
– the model must be an accurate representation of what will be
built in the field. If a designer stuck a sanitary tee where there
should be a combination, Revit will count a sanitary tee in the
estimate. Revit is just a dumb program. You need to survey the model
for accuracy and code compliance before you just export a quote.
You'll also need to make sure nothing is being missed, like a boiler
with a screw-up in the family that keeps it from being listed in the
schedule. We're not to the point of AI plumbers yet, so get a plumber
to sign off on the model. Better yet, as I've said before You
Need a Plumber designing your model in the first place!
