Cost Estimating Guidelines

[OneManWolfpack]

Construction cost estimating is not my forte. My go-to methods are RS Means and emailing reps. My firm attempts to compile bid price records from previous projects, which is extremely helpful when I find relevant items; however, I often find this resource lacking.

Most of the estimating I do is for long term planning and alternatives analysis, so coming up with "ballpark" numbers without spending too much time is more important than getting precise, project-specific estimates.

What are your typical methods/resources for budget cost estimating?

For example, right now I'm evaluating a WWTP expansion against pumping excess capacity needed to another WWTP. I have a prelim designs for both alternatives, and a good handle on lifecycle costs outside of construction cost estimates - this is where I feel like I spend WAY too much time.

Any advice would be greatly appreciated.

 

[QualityTime]

If your company is big enough you should have a base of historical actual tendered construction cost data from constructioning similiar WWTP's. Reduce it down to $/Mgal.

As far as operating costs speak to the owner for that data

 

[QualityTime]

If your company is big enough you should have a base of historical actual tendered construction cost data from constructioning similiar WWTP's. Reduce it down to $/Mgal.

As far as operating costs speak to the owner for that data. Break out the energy and chemicals and manpower and maintenance and reduce it down to $/Mgal

 

[BenJohnson]

If the cost estimate if to be the "engineer's cost estimate" to include in bid documents, then you must be as accurate as possible. That means you need to spend a lot of time calling manufacturer's representative, contractors, and other engineers to get a reasonably accurate estimate.

If this is for advanced planning and alternative analysis, then you don't need quite the accuracy.

Honestly, this is a good time for you to gain some knowledge on the subject. Cost estimating is a vital part of every engineer's career.

Whatever you do, don't give the board or council (or whoever is paying for the project) and cost number that is too low! Hell knows no wrath like an engineer who gives a low cost estimate.

 

[sjohns4]

I dont hesitate to call up and send a sketch to one of the local, reputable contractors. If you're looking at $/MGD be sure you're comparing apples to apples...secondary treatment plants vs. enhanced nutrient removal plants are apples to oranges.

We'll often do plant and large PS project estimates in pieces: $/yd of reinforced concrete + equipment costs + $/SF of building area + asphalt per ton + site work + anticipated manhours x rate + etc. I've found the more items I estimate individually the higher my estimate usually is, but the more accurate it is.

Assigning a labor estimate can be a tedious process but if nothing else if you're forcing yourself to think through what is required to install various pieces of equipment you'll get a better handle on how things are built and ultimately end up with a much "smoother" construction phase.

Labor costs can vary depending on the region where the project is too, for example just across the state line where prevailing wages do not apply labor is about half what it is here.

I'll second the caution of throwing out a low number to the owner...It's much easier to explain why an estimate was high rather than low.