manhour estimate

huangyhg

manhour estimate
i am doing a estimate of manhours. i did it items by items but i got a extremely low hour/drawing ratio. i mean way lower than normal. how do you guys adjust your estimate if you run into the same situation. thanks
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usually calculating a fee by task does run a lot lower than % of construction or $ per sheet.  the key is that you try to list all the tasks, but many times there are tasks you don't include (but obviously should) and there are tasks that many times have to be done twice due to project decision flows and changes of mind.
estimating hours is more an art than a science.  think of the times communicating with the architect to obtain information you need to actually start something.  also, as a whole, the design team does not operate at 100% efficiency.
if you are trying to get a figure to come up with a bid, compare the final $ to some percentage of construction costs, then adjust up or down to make the fee competetive.  if you've already won the bid, designate percentages to each stages design, assign percentages to them and see if the manhours based on the $ for each design phase is manageable.
unless you get a very detailed scope of work and a good set of drawings from the architect, estimating the manhour is a wag.  generally, the best info i ever get is a verbal description of the project.  i estimate the number of hours for design team meetings, analysis and design, detailing, coordinating my work with other consultants... and then double that number to account for extra meetings, the inevitable redesign effort for some part of the project, and the whatevers that always occur during any project.  i've been doing this for almost 15 years and the method has worked well for me to put together a fee, which i compare to % of construction cost and $$ per square feet.
thank you very much. what is the percentage of construction cost do you usually use in both commercial and petro chemical industries? i am following some guidelines but just like i said in the first post different mathods give me vast different result. just try to get good advice from the experienced.
the % of construction costs vary depending on the type of project.  the rs means building construction cost data handbook shows engineering fees to be 1% to 2.5% of project costs.  architects generally get 4% to 6% of the project costs.  supposedly, architects pay some consultants' fees out of their fee, but i'm not 100% convinced that happens for all projects.  some architects have told me they pay 15% of their fee to structural.  again, i'm not certain that's always the case.  perhaps they use 15% of their fee to pay for all consultants except mep.  some architects want my fee to be 0.75% to 1% of the project costs.  i've used the 4% to 6% to determine a fee based on expected costs of the structural portion of the project costs.
at one of my previous employers (an a/e firm), we used the following percentages:
* total fee = 6% to 8 % of construction cost (or more if possible)
* m/e/p and civil engineers get 40% of total fee
* structural engineer gets 18% of the remaining 60%
this works out to be roughly 1% of construction cost for the structural engineer.
i work for an engineering firm now, and i use between 1/2% and 1% of construction cost for a fee estimate, assuming all phases of work are included (calculations, drafting, submittal review, site visits).  obviously if my client does the drafting, doesn't want site visits, etc., then my fee is less.
daveatkins
thanks a lot everyone. happy holidays!
in refinery industry, how do you allocate engineering hours for different trades. i am talking about structural, instrumental, mech/piping, electrical... engineering. thanks