Estimating costs on land development projects?

[nutbutter]

Hello,

I'm wondering if anyone has a good reference for estimating costs on land development projects? Unfortunately, I've had poor mentors who were unable to provide insight into their cost estimating numbers. I used to have a large spreadsheet that broke out costs according to units (created by an engineer I don't have much faith in). This is ultimately what I would like to re-create, however, I'd like to have a little background on how the prices were determined.

I'm basically looking to be able to put together a bid for large land development projects. For instance, I'd like to come up with some cost figures for the following (this is by no means all inclusive):

Installed HDPE per LF (12" - 60")
Installed RCP and CMP per LF (12" - 60")
Installed PVC per LF (6"-18")
Fill material per CY
Asphalt pavement per CY
PCC pavement per CY
Wetland mitigation (per acre)
Curb and gutter per LF
Silt fence per LF
Sedimentation basin (LS)
Catch basins and manholes (Each)
SWPPP development and land disturbance permit (per acre or lump sum)
Archaelogical study (per acre or lump sum)
Sanitary lift station (LS)

Now, I know a lot of these costs are going to be highly variable. They'll change from site to site and region to region obviously. What I'm really looking for is how some of you other engineers come up with these estimates. Does it really require calling contractors, manufacturers, vendors, etc.? Or do many of you have a standard spreadsheet that's tailored to your area that you use to whip up a cost estimate in a matter of minutes? Cost estimating, like hydrology, is not an exact science, so I would think a general spreadsheet would be very helpful if one peforms work in a specific region where prices aren't likely to fluctuate as much.

Anyway, is there any reference/book out there that provides guidance for pricing land development jobs? Or do most of you do research with the contractors, vendors, suppliers, etc. to determine your prices for bidding?

Any help would be VERY appreciated! I've been wondering about this for awhile. I have no immediate need for my job, but some developer friends are always asking me to review bids from other engineers and I don't really have the experience to help them. I really want to get that experience so I can help them.

Peace,
Stoddardvilla

 

[LHA]

Free:

http://www.get-a-quote.net

For sale, web-based, books and/or CDs:

http://www.meanscostworks.com/

Engineering is the practice of the art of science - Steve

 

[civilperson]

State Department of Roads and DOT's publish bid sheets for projects. Use the items and units of the these compilations in a size comparable to the magnitude of your project. Apply inflation factors and material increase percentages as noted in Dodge Reports or Means. Do not forget mobilization and erosion control, (fewest items lumped into overhead gives most accurate estimate). Catch basins by types and MH's by vertical foot is my preference. Grading averages at 1700 cy/acre for a 1' change,(include no grading as a 1' change).

 

[BelspringKen]

The DOT bid tabs are a great place to start. As noted, make sure you use find a price based on a comparable amount of a product. Beyond that, you should probably call a couple contractors in the area.

Calculate your grading in CY. MH by vertical foot is generally the way I have seen it done. I often see sidewalk pavement done in SF or SY, not CY. A reinf. conc. retaining wall will have the concrete estimated in CY, and the steel in LB (pounds). Don't forget about disposal fees if you have a lot of demo.

You will have to call the locality in question for the permit fees.

As far as the lift station goes, I always have to talk to the guys who do that kind of work. Perhaps you could contact a vendor for that.

 

[cvg]

note that prices vary constantly. if you are creating a unit cost database you need to also keep track of the date so that you can adjust the unit prices to current dollars. Also keep track of quantities as most unit costs go down when volume goes up. Also be aware that contractors have to recoup all their costs for overhead and for items that are not estimated or bid. They will wrap all of this up in some of the bid items (usually the items that they feel will overrun). It is a bit of a gamble on their part, but often works to make more money. So, unbalanced bidding is commonplace, and can really skew the average prices in your database if you are not aware of it.

 

[LHA]

Regarding DOT Bid Tabs, the dates shown are the Awarded Dates, not the Bid Dates. A contractor is held to costs at Bid Date. No big deal usually; but heed cvg's advice RE: varying pricing.

With volatile items (such as bitum during an unstable oil market) and/or long bid time projects (a ten-year Turnpike extention): keep in mind you are not reading the prices when they were Awarded, but when they were Bid. You don't know the Bid Date.

Engineering is the practice of the art of science - Steve

 

[rmadrid]

best place is call the local contractors in that area to get prices if the public agencies do not have any number you may use.