Construction Engineering Design Estimation (MEP)

[EE123]

Hi,

I am working for a small MEP(Mechanical/Electrical/Plumbing) Consulting firms, and recently we have been looking into finding a better way to estimated the cost for Mechanical and Electrical design to submit for the bid (Do not want to over bid, or under bid). Is there a rule of thumb on how to go about doing this; lets say based on the Total cost of the construction or the square footage of the over all building. What do you guys use at your firm to come up with a good number? Is there a software that can do this? When there is a construction, is there a set budget for a MEP based on the total cost?


Thanks,

 

[alehman]

The method depends on the objective. For rough order-of-magnitude costs, sometimes typical square-foot number are OK, especially for typical construction types. For specialties, there's no substitute for experience. For more accurate numbers, detailed plan take-offs are usually necessary.

There are several estimating guides and software packages available. These can lead you astray if you applied without the benefit of real-world experience however. Costs vary considerable with market prices for materials, labor and with location.

http://www.rsmeans.com/

 

[davidbeach]

Means is certainly a good point of departure, but nothing beats experience. Labor and materials will split about 50-50 for most projects.

 

[ramski]

There is no better way of estimating than verifying all the parameters one by one if you are bothered of having your Bid over and or under bid. If it is rush, working overtime on it will make a difference anyway its just for say: a week.

For me its not practical to compare the cost of MEP against the total Construction cost specially if it is a BIG project. There is a slim chance of hitting it right on target. BUT as other always says experience is always the best.

 

[waross]

I have seen electrical estimating so detailed that every wood screw was counted. (actually the conduit footage was used to estimate the number of straps and that number and the number of junction boxes was used to determine the number of screws)
The justification was that the price of the screws is not important, but if you miss the screws, you also miss the labor to instal the screws.
respectfully

 

[jghrist]

I assume you are asking about estimates of design cost, not construction cost.

What we do is list all of the tasks involved in as much detail as practicable, estimate the time that would be required for each task for each category of personnel, then multiply by the salaries and use a payroll and profit multiplier. After all of this is done, then we do a sanity check (how reasonable is the overall result - if you come up with 2000 manhours to do something that you think can be done in a month by two people, something is wrong). Usually, the boss sits down and talks me into cutting the time estimates.

You need a feel for how much money the client has available. If you estimate much more, then you have to restrict the scope.

It helps if you have kept good records of how much it has cost for similary projects in the past.

 

[EE123]

Thanks for all your help.

jghrist,

you are right I am looking for the design cost rather than the construction. Is there a way to estimate how much the client is willing to spend on the design? Or can you estimate the cost based on the something like square footage or total construction cost? e.g. let say the total construction cost is $10,000,000 then the total money dedicated for design is 10% of that; out of that 10% the Architect would take 50% and the rest is divided between Mech/Elec/Plumb/structural/landscape and ... is there a percentage that I could use to bid for example Mech is 5% of the design cost and elec is %6 of the design cost?

Is there such a thing as charging let say $0.30 per SF for Electrical. So one would just multiply that by the total SF and get a good estimate.

Thanks,

 

[jghrist]

For some types of design, the design cost can be estimated as a % of construction. Most of our work is with utilities, and this is generally not the case. Too many complicating factors, like designing the installation of a 100 MVA transformer station may not cost much more than for a 50 MVA transformer, but the installed cost will be much higher because of the transformer cost.

Designing relay/control additions to an old station with crummy drawings may be pretty large % of the cost of the relays.

 

[dpc]

Most people use a % of construction cost as at least a sanity check. But the percentage will vary depending on the type of project.

For mega public works projects, total engineering costs were traditionally pegged at around 6% of construction. But for projects where you don't have billions of cubic yards of concrete, the percentage can range up to 10% or even higher for high-tech work.

You'll have to figure out how much of this total should be for MEP.

You can get another check by looking at past projects and figuring out how much it cost per drawing and do an estimate that way.

I like to first do a zero-based cost estimate first, then do a check as % of construction and cost/sheet.

Also, if this is repetitive work, like designing Home Depots or Walmarts, engineering as a % of construction will be less.

You might check the NSPE website to see what resources they have. They used to have books available on the business side of consulting work.

You might also check US Army Corps of Engineers and Naval Facilities websites for available public data and guidelines.

(Don't forget to allow for the 15% that the architect or lead engineering firm will be tacking onto your fees.)