construction cost estimate

huangyhg

construction cost estimate
i'm facing another dreaded construction cost estimate. this is for a water treatment facility in the northeast u.s.
here are my installed unit costs:
foundation wall concrete: $430/yd3
retaining wall concrete:  $430/yd3
slab on grade (finished): $350/yd3
footings:  $260/yd3
reinforcing:  $0.70/lb
steel roof deck ((22 ga): $1.30/ft2
steel joists (up to 50ft): $.75/ft2
cmu (8" reinforced):  $8.00/ft2
honestly, i don't have a lot of confidence in these numbers.  so, i'm wondering what others in my vicinity are using for these items.
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your concrete and rebar are about 80 - 90% of what i use for bridge projects.  most state dot's have unit prices and previous bid tabs available through their websites.  that should get you close on some of the items, and you may even be able to find some "building" or facility items.
another thought is to use the dot prices to correlate prices from other sources (means, etc).
bridge projects tend to be a bit higher due to the fact that they are under the purview of state dots (i.e. gov't regulations galore)
some notes to ponder:
1. i would compare these to rs means published data? you can correct for your locale.
2. is this a union job or non-union> this makes a difference.
3. is davis-bacon wage determination applicable?
4. how is the locale economy in the construction area?
5. io live in florida, for a period of almost two months, no one could get concrete. lots of job sites shut down and the price of a yard hit near $100!! are you having similar crises in the construction site?
regards,
regards,
lutfi
we don't subscribe to rs means anymore.  when we did, it seems that there was a big discrepancy between means estimates and dot unit prices....on the order of 50 to 100%.  our non-dot estimates using means always seemed to come out low, even when adjusting for region, etc.  dot unit prices work ok for dot projects, but gave high estimates for other construction.  for non-dot work, both guidelines seem way off to me.  i think this municipal project will be union work, and i don't think we are seeing any unusual economic circumstances.  oh, i much prefer stresses and strains to dollars and cents.
you can also get ahold of recent issues of enr which has a section in each issue discussing price trends.
i agree that rebar seems low, same with masonry.
of course, costs are also tied to the size of the job, complexity, non-pay items that are lumped in with the bid items as well as how busy your local economy is.  for example, around here, the contractors are so busy, they are not inclined to lowball the bids just to get it.  therefor, the bids are coming in quite high.  be careful because the rising fuel costs are really playing havoc on all construction costs.
unit prices are so variable because so much goes into determinining what it will be: is it at the beginning of the job or later, how much profit is on the item, how much overhead is assigned to the item, is the job complex, what is the access...
as a contractor, we never use unit prices to prepare bids, it is simply the output required by the agencies.  we do use them for a reality check but the most important aspect for us is the mh/unit.  the risk is in the labor (usually), and provided your have your takeoff correct, the job costs will come from labor productivity, not unit cost.  material costs are what they are, call around and see what the market is, and subcontractor quotes are an unknown until bid day.  it is always a little bit of a competition to see whos subcontractor "plugs" were closest when bid day comes around.
also, most estimating manuals seriously underestimate the overhead and profit.  it's usually 15% (+/-) of total cost, which include field indirects.  that means that the project manager, engineers, superintendent, field office, etc. are not inlcuded in the 15%, so add them in.
regarding your specific costs...in california, on a union water treatment plant, we did the following...
concrete: we averaged $850 / cy concrete in-place (not including excavation)so i think your costs are low.  (our plant was half retrofit/half new construction.  $600/cy may be closer for a new plant.
reinforcing:  go up to $1/lb, $2/lb if it is epoxy coated.
steel roof deck ((22 ga): not sure, but it usually costs about $1.5 just for the materials.
hope that helps.
the prices look awfully cheap. material prices have been sky rocketing for the last two years. also, unit prices, especially for concrete, is very dependent on the complexity of the work. the bulk of the cost for concrete is forming. a common measure of complexity of the for forming is the form factor which is the ratio of the square foot of forms requred for a pour to the volume of concrete in cubic yards - the result (a ratio with out units) indicates the amount of forming in the unit price. the higher the ratio, the more expsive the work. i would suggest you strike up a relationship with a local contractor or two who could give you some pricing help. i provide complimentary budget estimates, and i occasionally hear about private work that i might otherwise have missed.
means is a good gude if used properly. they provide a lot of info on the the price breakdown, incuding enough to adjust for specfic projects. for examle if their model wall has a form factor of 12 and yours has 24, double the cost of the carpenters.
thanks for the tips.  great advice.  in addition, i have a lot of excuses if my estimates are off.  no wonder i'd rather deal with stresses and strains.  the solutions don't change from day to day...