Summary

These notes are a rough guide for the beginning of Estimating, students should refer to their book for in depth discussion.

i

CMGT 343 Estimating Table of Contents

Summary...........................................................................................................................................iTable of Contents............................................................................................................................iiiChapt 1.............................................................................................................................................5

Why Estimate?...........................................................................................................................5Owners perspective........................................................................................................5Contractor’s perspective................................................................................................5Who are estimators?.......................................................................................................5

Estimating Process.....................................................................................................................6Types of Estimates.....................................................................................................................7

/ Project Comparison/ Parametric (Conceptual)............................................................7Square Foot or SF (Preliminary)....................................................................................7Assembly........................................................................................................................7Unit Price/ Item/ Quantity survey (Detailed).................................................................7

The Estimator (1-4)....................................................................................................................7Contract Documents 1-7............................................................................................................8Plans and Specs..........................................................................................................................8

Addenda.........................................................................................................................8Chapt 2.............................................................................................................................................8

Agreement Provisions................................................................................................................8Bonds.........................................................................................................................................8Insurance....................................................................................................................................8

Chapt 3.............................................................................................................................................8CSI MASTERFORMAT...........................................................................................................8General Conditions (3-7)...........................................................................................................9Supplemental Conditions (3-8)..................................................................................................9Technical Trade sections (3-9)...................................................................................................9Alternates (3-10)........................................................................................................................9Addenda (3-11)..........................................................................................................................9Errors in Specs (3-12)................................................................................................................9

Chapt 6.............................................................................................................................................9Overhead, Contingencies or Mark ups.......................................................................................9

Overhead (6-1,2,3).......................................................................................................10Contingency (6-5)........................................................................................................10Profit 10Escalation.....................................................................................................................10

Chapt 7...........................................................................................................................................10Labor........................................................................................................................................10

Union Labor.................................................................................................................11

ii

Non union labor (open shop).......................................................................................11State/ Local Public Works...........................................................................................11Davis Bacon wage........................................................................................................11

Other Resources.............................................................................................................................11Equipment................................................................................................................................11

Rental Rates.................................................................................................................11Contractor owned.........................................................................................................12

Materials..................................................................................................................................12Time 12Money......................................................................................................................................13Subcontracts.............................................................................................................................13

Estimating......................................................................................................................................13Parametric Estimating Total Cost Method (TCM)..................................................................13Procedure for Preliminary/ Parametric Example (Total Cost Method)...................................13Preliminary/ Parametric Example............................................................................................13Square Foot Estimate...............................................................................................................14Procedure for SF Estimate.......................................................................................................14SF Example..............................................................................................................................15Unit Price/ item estimate..........................................................................................................16Unit Price Data Book Data......................................................................................................16Line Item Bid Procedure..........................................................................................................16Line Item Example...................................................................................................................17Excavation................................................................................................................................19

Soil Type......................................................................................................................19Swell & Compaction....................................................................................................19Equipment....................................................................................................................19New Site Grades and Rough Grading..........................................................................20Top Soil Removal........................................................................................................20General Excavation......................................................................................................20Backfilling....................................................................................................................21Asphalt Paving.............................................................................................................21

Concrete...................................................................................................................................21Estimating Procedure...................................................................................................21Reinforcing..................................................................................................................22Vapor Barrier...............................................................................................................22Expansion Joint fillers..................................................................................................22Concrete finishing........................................................................................................22Concrete Curing...........................................................................................................23Forms 23

Wood........................................................................................................................................23Floor Framing..............................................................................................................23Wall Framing...............................................................................................................24Ceiling Assembly.........................................................................................................25Roof Assembly.............................................................................................................25

Thermal and Moisture Protection............................................................................................26Insulation......................................................................................................................26

iii

Roofing........................................................................................................................26Doors and Windows.................................................................................................................26

Windows......................................................................................................................26Doors 26

Finishes....................................................................................................................................27Drywall........................................................................................................................27Flooring........................................................................................................................27

Electrical..................................................................................................................................27Mechanical...............................................................................................................................27

iv

Chapt 1Course goal: expose students to the process of estimating and develop skills need to produce quantity estimates. This course will not make you a skilled estimator, only OJT in the construction field can to that. This course will provide a solid background in the tools, processes, and techniques to apply in the field.

Why Estimate?

Owners perspective

Need a way to develop budgets and cost proposals. Owners estimates are often done before design is completed, design may only be about 5% complete, really only conceptual.

Contractor’s perspective

Contractors will “Bid” a project. Need to understand what it will cost and best method to build a project. Contractor estimate will be the most accurate. Normally done after design is finalized.

Who are estimators?

Typically people who do the grunt work to win the jobs. Extremely knowledgeable about construction cost and methods. Their knowledge combined with PM’s field and contract smarts will win profitable jobs. Sample organizations:

5

What are the wages of these individuals?Occupation Guess IndustryOwner 0 - ?President $100K +PM $60 – 80KEngineer $50 – 60KScheduler $40 – 60KSafety $40 – 60KSuper $40 – 70 KEstimator $40 – 100K

Estimating Process

Review overhead10 factors to consider when deciding to bid:1. Type of project2. Size of project3. Location4. Who the A/E or Architect is & quality of plans & specs5. Who the owner is6. Specialized work7. Anticipated problems

6

8. Safety considerations9. Need for work10. Bonding capacity

Types of Estimates

/ Project Comparison/ Parametric (Conceptual)

The roughest estimate. Normally only done to determine a “ball park” price. Cost of new construction based on past projects. Need to be careful with this approach, must use recent and similar projects. Used by owners to determine if project is go no go.

Square Foot or SF (Preliminary)

A little better than preliminary but still typically only used as a guide. Again mostly used by owners to gain approval of project/ or decide if project is viable. Design is incomplete, maybe only 20-40%. Use published data on SF cost to estimate proposed cost of project. Data is published in means BCCD book.

Assembly

Intermediate estimate. Assembles typical work into groups ie excavating, forming, and pouring concrete spread footers, find a price by LF. Need to know how project will be built, design may be 40-70% complete. Normally used by engineering and architectural firms when developing cost of a project. Used by Contractors for repetitive things they do in combination with unit price estimate. Will not be done in this class, but next term we will learn how to build assemblies.

Unit Price/ Item/ Quantity survey (Detailed)

Final and most accurate estimate. Based on completed design and how construction will actually be performed. This combined with assemblies is how contractors bid projects. The item estimate take the most amount of time, it is expensive for contractor to do, yet very important. This class will focus on this type of estimate. Quantity Survey are typical of Highway jobs.

The Estimator (1-4)

Must have…1. Read & quantify plans2. Knowledge of math3. Patience4. Able to visualize project5. Construction experience6. Knowledge of labor productivity and operations7. Computer guru, excel, data base, specialized commercial software8. Work under pressure

7

Contract Documents 1-7

Plans and Specs

Projects designed and let for bid or negotiation. Specifications, particularly the “general conditions” form the rule of how project will be administered. These add cost to a project but a subject for an entire other class. Need to understand the plans are not by themselves, specs also form the contract and need to be gone over before a project is bid.

Addenda

Modifications to the contract documents before bids are received.

Bids must be made based on the contract documents not just the plans

Chapt 2

Agreement Provisions

Scope of the workTime to completionProgress PaymentsRetainageSchedule of values

Bonds

Bid bond, ensures contractor will enter into contract if bid is accepted.Performance bond, guarantees to the owner that the project will be completed if contractor defaultsPayment bond, guarantees workers and suppliers will get paid

Bonding rates based on experience, total cost of work, past record, 1-3%

Insurance

L&I required by law, rates based on incidence rate & type of work, 1-30% General Liability use of motor vehicles, third party, in this class use 3%

Chapt 3

CSI MASTERFORMAT

Most widely used method of organizing and coding construction work. You need to memorize the CSI MASTERFORMAT. All construction documents, estimates, costs, budgets, bids etc are organized after the CSI MASTERFORMAT.Divisions:1. General Conditions, the rules of the contract, payments, submittals, etc2. Site Work, excavation, backfilling, pavement, landscaping

8

3. Concrete, footings, slabs, beams, walls, reinforcing4. Masonry, CMU, brick, rock5. Metals, fasteners, structural steel, metal studs, stairs6. Wood and Plastics, framing, floors, wood decking, fiberglass, countertops7. Thermal & Moisture Protection, insulation, roofs, sealant8. Doors & Windows, all shapes and sizes, curtain walls 9. Finishes, Gypsum board, terrazzo, wood floors, carpet, painting, wall papr10. Specialties, wall hangings, partitions, bathroom accessories11. Equipment, food service, retail, medical12. Furnishings, casework, furniture13. Special Construction, clean rooms, pre-engineered buildings, underground tanks14. Conveying Systems, elevators, moving walks, bridge cranes15. Mechanical, plumbing, fire systems, HVAC16. Electrical, wiring, receptacles, lighting

General Conditions (3-7)

Generally how owners does biz, right and responsibilities of all parties

Supplemental Conditions (3-8)

Specific to this job

Technical Trade sections (3-9)

Follow CSI, details that accompany plans, ie paint requirements, steel type, performance requirements ie work in –20 to 110 degrees F

Alternates (3-10)

Typically deductive or additive items because the owner has a tight budget and not sure he can afford them.Also gets up front competitive if he adds them later on

Addenda (3-11)

Errors in Specs (3-12)

How are plans and specs made?Will have errors or holesRFI = Request For Information = ClarificationBecomes Change Order = Modification when RFI answer involves more time or $

Chapt 6

Overhead, Contingencies or Mark ups

Things added to the final cost of items and subcontractors to include cost that are not included in an item by item estimate.

9

Overhead (6-1,2,3)

For small contractor may be a small normally 10% to large contractor that calculate a different OH # for each project.OH cost normally separated in field and home Home Office OH salaries, office rent, electricity, etc, generally stated as a percentageField or job OH cost: trailer, super, materials handling, Bonds, telephone, etc, generally listed by line item + a percentage.

In this class we will not detail this out in our bids or estimates. But you need to understand normally an estimator will make a list of line items of these things and account for them in an estimate. We will use a straight 10%.

Contingency (6-5)

May put this into a bid if rushed to finish estimate or the work is particularly difficult ie rehabilitation work. May add to you bid if you are second low on a number of bids. This value may be about 1-10%.

Profit

How much $ does the company want to make on this project after all cost? Depends on the market, in tight markets this number is 3-5%, in good times it may go as high as 15%.

Escalation

May put this into the bid if not expected to do the work for awhile, or you are escalating the cost of due to a particular owner or Architect. Ie brother’s car shop in Bellingham, GC who doesn’t really want to but builds custom home (mansion) for client.

Chapt 7

Labor

Very general rule of thumb, labor is about ½ the cost of construction.Labor rates are published in cost books or required by state, federal or union rules. Labor is very much a function of supply and demand. In Seattle a skilled carpenters can do very well, in Klictitat co carpenters make only $10/ hour.

Labor in terms of cost to a contractor is not just $ paid to workers. Contractors must pay what is called labor burden. Burden is fringe benefits, mandatory taxes, (FICA, L&I), unemployment insurance etc.

When using labor rates must make sure you know what is included in the $/hr figure.

Labor productivity is a function of: labor availability, working conditions, climatic conditions, job site set up

10

Union Labor

Mandated rates for contractor that are union shops. Must make sure are estimating with currently negotiated contract.

Non union labor (open shop)

Contractor will maintain database of labor cost per region, city they do work in. If haven’t done work in this city for awhile, may use cost guides to adjust labor cost. Ie Means location codes.

State/ Local Public Works

Mandate a labor rate to be paid in areas of the state. Go over hand out in class. But estimate needs to reflect cost of obtaining good skilled labor. IE VK Powell in Kickitat county with carpenters State wage says $10/hr, but his skilled carpenters from Yakima won’t work for that wage. If you want an efficient job, need to pay more than the “state” required wage sometimes.

Davis Bacon wage

Federally mandated wage rate, normally based on what unions are paying in metropolitan areas. As above need to use care in applying to rural settings.

Other ResourcesConstruction involves combining or managing 5 resources1. Labor2. Equipment3. Materials4. Time5. MoneySubcontractors may constitute a major portion of 1-3

Equipment

Basically two types; contractor owned and rental. Your Means book provides rental rates in the General Requirements section. When we estimate work in this class we will use items that include the cost of the equipment in the crew listings. But if you need to estimate equipment cost for a specific project, type or phase of work Means is a good place to start.

Rental Rates

Rental rates include: vendors cost of ownership, OH, & profit.We will use the means book in this class.For rental rates go to Division 1, section 016 in MeansMeans list “operating cost” less operator ie fuel, etc and “rental cost” If you need an hourly rate for both operating and rental cost you must calculate it.Note Means lists “Crew Equipment Cost” which is based on a weekly rental rate.

(Operating cost +rental rate)/ per hour = Crew equipment cost/8

What’s the hourly rate that includes both rental and operation cost for a “whacky packer” page 19.

11

$31.55/day /8 hr/ day = approx $4/hr

What’s the hourly rate that includes both rental and operation cost for a “Backhoe, ¾ Cy capacity” page 19.$218/day/ 8 hr/ day = $27.25

Need to be real careful what cost you quoate from Means or any book, be sure you understand what they are including.

How do contractor estimate rental costs?Get copies of rental rates from vendors they normally use, or in the location of the job site, this can change drastically. Also need to be aware of delivery cost. For a small piece of equipment the contractor may just throw it in the truck, for heavy equipment there may be a $500 charge for both pick up and delivery.

Contractor owned

Cost continues whether or not the equipment is being used or not. (reason a lot of contractor don’t own a lot of equipment)

General rule of thumb is that Contractor ownership cost is about 70% of rental cost.So for “Whacky packer” above contractor ownership cost is about(0.&) x ($31.55/day) = approx $22/day

Contractors use various methods to establish ownership cost to include in their bids. But this rule of thumb is what State/ federal and Architect use to establish “fair and reasonable” price during change orders or force account work.

What is Force Account work? Typical of highway work, when in a changed condition the contract will specify what rate equipment will be paid at.

Materials

In this class we will use the Means BCCD book for material prices. Real contractor’s use quotes from local vendors. This is done over the phone or through price list. Typicall a formal process is developed so estimators are on mailers form vendors and prices are adjusted accordingly. This is going to electronic data…but not quite there yet.

Also Sweets Catalog is a collection of Manufactures Catalogs. Contractors use this to find material that will meet specs & call vendors to get current prices. Sweets has several books and generally laid out following the CSI MASTERFORMAT.

Need to include the cost of taxes

Time

Topic of another course, scheduling. Estimates on big jobs are done in conjunction with the schedule to determine the # of crews, shifts, and method of construction.

12

For this class you need to know time has a value associated with it. As a general rule the contractor that can complete a project on time or ahead of schedule will make $.

Money

Major resource to contractors. They typically have to fund a certain portion of the work until they are paid. Generally a contractors is paid for his work by periodic payments. Example of the ships building when $1M invoice got delayed.

In this class we will assume $ is available to finance the start and finish of all projects.

Subcontracts

How most of the work gets done nowadays. Some consider the subcontractors as resources that need to be managed. In this class we may get prices from subs to perform a portion of the work.

Estimating

Parametric Estimating Total Cost Method (TCM)

Method to estimate cost of similar construction. Used a rough guide for preliminary, feasibility or check on detailed estimate. Most contractors will contain data bases that contain this type of information.Uses a TCM to adjust cost based on complexity or projectTCM= SF0.9 buildingsTCM= SF0.6 complex projects, hospitals, plantsWhere SF = Size Factor = Proposed size/comparison size

Procedure for Preliminary/ Parametric Example (Total Cost Method)

1. Find similar projects to the one you are estimating, establish $/SF cost2. Set up an organized table to work from3. Find Size Factor, SF= Proposed Size/ Comparison size4. Find Total Cost Multiplier, TCM= SF0.9 buildings, TCM= SF0.6 complex projects5. Find Adjusted Unit Cost by multiplying TCM x comparison unit cost.6. Find Projected Total Cost by multiplying Adjusted Unit Cost by project SF.7. Round to an appropriate value. Never use cents in final answer. For preliminary estimates

round to nearest $100 or $1000.8. Ask your self does this value make sense?

Preliminary/ Parametric Example

Given: 4000 SqF small office building, and want preliminary cost

13

Known: 5500 SqF office building @ $675K, 2000 SqF office building @ $215K

Example # 1 Example # 2Total Area SF 5500 2000Total Cost $475K $215KUnit Cost $/SF $675K/5500= $122.73/SF $215K/2000= $107.50/SFSize factor 4000/5500= 0.73 4000/2000= 2Cost Multiplier 0.730.9= 0.75 2.00.9= 1.87Adjusted Unit Cost $122.73 x 0.75= $92.1/SF $107.5 x 1.87= $200.6/SFProjected Total Cost $92.1 x 4000= $368K $200.6 x 4000= $802K

Cost MultiplierTCM= SF0.9 for buildings

Rounded to nearest $1000, notice range $368K to $802K. Need to be very careful with these types of estimates, should use higher value when giving to client or management. Why? If project gets approved at higher cost and actually cost less can add things. If a project gets approved at lower cost and actually comes in higher, project may get killed, or will cause plenty of “illwill”.

Square Foot Estimate

Similar to preliminary and only a little more accurate. This method uses published data, e.g. Means Square Foot Cost and your book BCCD has a section in the back with SF cost. This is used much more often in industry by A/E firms to get an early estimate of a projects cost. Must be very careful when using this method because it’s not very accurate. Joe Robbie stadium in Miami, owners or A & E firms tried to use this as a bench mark SF cost guide. What they didn’t know was the owner ran low on money at the end, and lot of “extras” were cut from the project like paving the parking lots, finishes were left “rough”, etc. When A/E firms used this as a SF guide the value was mistakenly low.

SF cost are also useful as a rough guide for estimators bidding projects. If bid has a SF cost that is out of line something may be wrong.

Procedure for SF Estimate

1. Determine the type, SF, # stories, and perimeter of proposed building.2. Determine the general type of construction, i.e. steel frame, exterior cladding, and generally

if proposed building is economy, average or luxury.3. Look up SF cost from Means and multiply proposed building SF times look up value.4. Preferable to use SF cost book but in this class we will use Division 17 in your book for SF

cost, remember these are average prices.5. Use ¼, median, ¾, e.g. ¼ means 25% had lower cost the this value, ¾ means 75% had lower

cost than this value. Use “judgement” to choose correct percentage.6. Find your SF cost then multiply by the city code.7. Then multiply it by the size code. Get credit for size factor.

14

SF Example

Want to build a 128,000 SF Fred Myer in Ellensburg, What is an estimated cost based on SF? City of Ellensburg has many histrotical requirements & site work with moving a stream.Only information we have is a department store @ 128,000 SF

Got to table in BCCD page 473 find total cost of ¾ based on stringent requirements of city of Ellensburg of $63.80/ SF. What if Bi-Mart was coming to current location?

Cost = 128,000 x $63.80/ SF = $8,166,400

City code, or Location factor, page 650 use Yakima$7,942,400 x 102.2 = $8,346,100 rounded to nearest $100

Size factor page 574 (explain why you wouldn’t use retail store)Proposed / typical size from chart128,000/90,000 = 1.42 SHOW OH

Enter area conversion scale on chart on pg 574Find cost multiplier of .97

$8,346,100 x 0.97 = $8,096,000 rounded to nearest $1000

A/E may use this value as a preliminary figure. Bidder may use this to check unit price bid, e.g. what if bid estimate came in around $5M?SF ExampleFred MyerSF BCCD

$/SF pg 473

Cost

128,000 63.8 8166400

Location Factor costBCCD pg 650 Yakima

1.022 8166400 8346061

Size Factor 128000/90000

1.42 Final Cost rounded to $1000

Cost multiplyer from page 574

0.97 8346061 8096000

15

Unit Price/ item estimate

Construction Estimate deals with 5 or 6 resources, need to account for:1. Labor, trades and OH types2. Equipment, bulldozers, cranes, rentals3. Materials, bricks and mortar4. Time, how long something takes and scheduling5. Money, how much the contractor has to finance, mark ups6. SubcontractorsIn this class we will use Means for costing data to develop unit price estimates. Very few contractors use Means, except for a check or starting point. They use their own “means” developed over the years of contracting. So what we use is similar but not the same as each contractor will have developed.

Unit Price Data Book Data

How we will do our estimates, by using the Means BCCD book.Labor, Equipment, & Materials are combined to form the estimate. OH is included in these line items or added at the end. In this class we will develop estimates with “bare cost” then add our own mark ups.Estimate is set up with a hierarchy: Phase (one of the 16 divisions) Task, work that requires resources of material, time, equipment, material to complete e.g.

build concrete retaining wall (excavate, form, pour concrete, finish) or lay pipe (excavate, place bedding stone, place pipe, backfill)

Line item, the smallest individual unit of work listed in BCCD. E.g. excavate, form, pour concrete, finish are all line items.

Line Item Bid Procedure

This is a process I want you to follow, most companies do something similar, mostly what is different is amounts of mark ups and where or when they are applied in the estimate. Try to keep it simple.1. Determine unit quantities from plans and specs. Try and do the same procedure every time,

ie go left to right or clockwise on drawings. Estimate as the job gets built, ie excavation, footers, floors, etc

2. Apply means BCCD to find bare cost for Materials, labor and equipment.3. Apply mark ups to bare cost: Materials 8% Labor Mark up 25-50 %, based on crew Type and inside back cover of BCCD. Only apply

Column B & C. For example 022-286-0010 uses crew B-10B, mostly equipment operator (med), from inside back cover Column B=11.4% then mark up = 11.4+16.5 or about 28%

Equipment mark up 10%4. Combine Materials + Labor + Equipment to obtain subtotal5. Add mark ups:

16

B & O Tax use 0.5% this is mandated by state and is based on volume and type of work contractor is classified as

Insurance, use 1.5% percent we’ll use this as liability and builders risk, rates based on industry and developed track record

Bond use 2%, normally these are prorated by value ie 0-$1M is 2% , $1-10M is 1.5% Overhead is 1-10% depends on how much you account for in general conditions Profit 2-10%, based on size, complexity, need, etc

Line Item Example

Example from page 180 Framing, Sills Treated LumberShow a line item for framing using 2” x 4” treated lumber, 06110-560-4600See “UNIT” in means is in MBF or 1000 Board Feet, also known as mfbm or 1000 feet of board measure:BF=(WxTxL)/12, W = with, T=Thickness, L=LengthHow many MBF in 800 studs?, where stud is 2”x4” by 8’MBF = ((2”x4”x 8’)/12)x800studs/1000BF/MBF = 4.27MBFTypically dealing with wood you include a waste factor, depends on project, amount and type of framing, ie small project not a lot of cuts 2-3%, large custom built houses framing project 5-10%.

If your project required 850BF of treated 2”x4” lumber for sills the material would cost:BCCD ref 06110-560-4600 page 180($985/1000BF) 850 = $837.25 remember this is bare must add mark ups, O & P

Labor to frame is similar, Wood framing Studs, 8’ wall, manual nailing say 2MBF2” x 4”, your labor cost would be: pg 181 BCCD ref 0611-560-6020

($850/MBF) x (2MBF) = $1700 remember this is bare must add mark ups, O & P

Backyard Basketball Court, just form, WWF & CreteForm with 2”x6”x10’ boardsSOG 20’ x 20’, 400ft2, 80LF, (400SF)x(51/2”x1’/12”)/27CY/CF=6.79CY Plus 10% waste, use 71/2 CY crete

17

SOG 20' x 20' basket ball courtForm, WWF, cretePerimeter is 80LF

80

SF is 400SF

400

CY of crete is 7.5CY

7.5

Item pg BCCD ref MTL Labor

Equip

unit measure

unit $mtl $lab $equip total

Form 96 03110-445-3000

0.32 1.42 0 80 LF 26 114 0

WWF 107 03220-200-0200

10.55 16.25

0 4 CSF 42 65 0

Crete 110 03310-240-4700

74 26.5 0.41 7.5 CY 555 199 3

623 377 38% mtl

0.08 50

C-14e use 11.5+16.5 28%

0.36 135.85

Equip 10%

0.1 0

673 513 3 1189B&O 0.005 6Insurance

0.015 17

Bond 0.02 23OH 0.05 59Profit 0.1 118

total 1415Bid 1415

18

Excavation

The first work typically done on a construction project. Need to determine amount of soil to be excavated , cut or filled, back filled, compacted etc.You will learn to calculate excavation quanitites from topographic maps, excavation requirements for footings, slabs, and parking lots. Also we’ll learn how to calculate asphalt paving requirements.

Soil Type

1st thing an estimator will consider. Type of soil impacts cost of excavation, fill or disposal. For example, most specs say to remove excess material from the site. If this material is clean topsoil, the topsoil may be sold or at least delivered for free, but if material is unsuitable for topsoil contractor may have to pay to have this material deposited somewhere.

Example, building Child Care Center, had a change order to increase the size of the parking lot. This requires excavating more soil than in original contract. But also had a ball field project that needed fill material. I had the Child Care Center contractor deliver the soil to the ball field and got a credit from the ball field builder.

Swell & Compaction

Soil expands when it is dug up, called swell, or % gained above original volume. When soil is delivered to the site and compacted this is called shrinkage, % of volume loss.

Percentage of Swell and ShrinkageMaterial Swell Percentage Shrinkage PercentageSand and Loam 10-18% 95-100%Loam 15-25% 90-100%Dense clay 20-30% 90-100%Solid Rock 40-60% 85%

ExampleGravel sub-base for concrete slab. 100’ x 100’ x 6”, How many CY do you order from the pit? Assume shrinkage of 95%Required CY=(100’ x 100’ x 6”/12’)/12ft3/CY = 185.2 CYCY with allowance for shrinkage = 185.2CY/0.95 = 195CY

Equipment

Should know generally what equipment is used for what jobs. Selection is of prime importance, based on economics, ie backhoe or large excavator, backhoe is cheaper but less efficient, large excavator very productive but very expensive.Shovel, all excavations require some hand work, but always kept to a minimum.Front End Loaded, wheel or track, used in pits, large excavations, can load trucks directly.Bulldozer, shallow excavations, clear and grub, roads, leveling.

19

Backhoe, mainstay of smaller construction because is so versatile, basements, trenches, pier footings etc.Scrapper, mostly just for roads or very large sites, can cut, transport and fill soil.Grader, just for leveling.Excavator, digs large holes, attachments for breaking and moving rock.Small “landscaping” ie bobcats use in tight locations, residential.

New Site Grades and Rough Grading

From site plans can get topographic information to calculate the amount of cut or fill required at a site. Cutting is removing soil, fill is bring soil to the site to raise it to the requires level.GO OVER EXAMPLE FROM SITE WORK HANDOUTCLASS ASSIGNMENT SIMILAR TO EXAMPLE.

Top Soil Removal

Specs normally require top soil be spread over any areas that were disturbed. Top soil depth varies from almost nothing to many feet. Specs will say to what depth to save topsoil. If there isn’t enough soil, may be required to buy topsoil. Typically this topsoil is striped off and saved on site.

General Excavation

Handout copies of pages 107-117Normally need to dig for footings, basements, parking lots etc. For footings need to account for space for the workers to form up footers. Normally this distance is 1-2’. Deep excavations need to be sloped to prevent cave in, this slope is determined from the “angle of repose”. If not sloped must use sheet piling, in trenches must use cave in protection devices.

MaterialAngle of ReposeWet Moist Dry

Gravel 15-25 20-30 24-40Clay 15-25 25-40 40-60Sand 20-35 35-50 25-40

Depth of cut = Top of the grade – bottom of fill under slab or footing. If top soil has been removed then deduct this from depth of cut.

To determine amount of excavation, need to find:1. Building footprint2. Distance footing projects from wall3. Working space required between footing and soil (normally 2’)

20

Angle of Repose

ExcavationSoil

4. Elevation of existing land5. Type of soil, found from boring samples.6. Whether excavation is sloped or sheet piled.7. Required depth of excavation, found by subtracting bottom of excavation elevation from site

elevation.

Show average length of cut as shown on page 109

Go thru example on page 110.

Backfilling

Need to replace soil back against the footing. Best method is to calculate area of back fill required and multiply be LF of footer to find CY. Will also need to spread topsoil to get to finish grade. Specs normally require at the very least reseeding and normally will require landscaping ( almost always subcontracted out.

Asphalt Paving

Typically has four layersCompacted subgrade (compacted the existing material)Subbase course (normally 6” of gravel or crushed rock) Binding Course (asphalt normally about 2”)Wearing course (asphalt normally about 1”)

Asphalt paving is almost always subcontracted due to specialized equipment required.Will want to plan you project normally put the binding course down early, to get the site out of the mud, then wearing course is done last to look good.

Concrete

Handout copies of pages 126-129One of the most versatile construction materials. Easy to work with, very strong, and made into almost any shape. Mostly use for foundations, slabs, beams and columns, but can be used as an architectural feature, ie Psychology building.

Concrete is made form Cement, water and aggregates(sand and rocks) Too much water makes weak concrete. Can be specified to various strength levels, typically get 3000psi concrete from the batch plant (this is called ready mix). But with certain admixes can get concrete over 10ksi. Always sold by the CY, includes delivery, may be additional fees for short loads ie less than 4CY, or on Saturdays. Concrete take time to cure, normally about 3 days, wait at least a couple of days before putting materials on it.

Estimating Procedure

1. Review the specs for: Type, strength, color of concrete required.2. List each concrete item required on the project.

21

3. Determine the quantities from the drawings, footings can be found on the profile views of wall sections.

Go thru example on page 126 & 127, show how to build spread sheet like one on page 132.

Explain: Footings, simple spread footing. Formed piers, foundation walls, grade beams, SOG, roof slabs.

Reinforcing

Handout pages 138-142Reinforcing bars, or rebar or deformed bars, what gives concrete it’s tensile strength. Rebar is sized by #’s, #’s represent the # of 1/8th of an inch it’s diametr is eg #3 rebar ahs a bar diameter of 3/8”. Rebar is estimated by the LF but bought by $/100 pounds or $cwt. Specs may require special costing, ie zinc/ galvanized or painted, this thyoe of rebar is much more expensive and must be special ordered. Need to allow for splicing & waste, see splicing lengths on page 140. Normally rebar is mostly fabricated in the shop and sent to the site, less waste and easier to work on in the shop. Also rebar needs to be specially placed in the concrete, to ensure it provide the proper tensile strength and coverage. Use “chairs” or blocks to raise rebar.

WWF or Welded Wire Fabric, used mostly in slabs but also as “temperature” steel in columns and beams. This mesh is specified as 6x6 10/10 which means the wire spacing is 6” x 6” and it uses #10 gage wire. WWF is sold by the roll, (roll = 750 SF), unless very small quantity is required. Therefore when estimated need to determine how many rols to buy.

Show example pages 141-142, go thru continuous footing long and short bars, Vertical & Hz wall bars, and dowels (error, should read 2’ dowels)

Do example of wire mesh reinforcing, page 146, find # of rolls.

Vapor Barrier

Polyethylene is laid down under concrete to prevent moisture from coming up through the slab. This is division 7 stuff but normally estimated with the concrete work.

Expansion Joint fillers

Made from ashpaltic materials, or sponge rubber, as required by the specs. Almost always between a slab and a vertical surface. Estimates by the LF and come in sizes ranging from ¼” to 8 “.

Concrete finishing

Depends on the finish required, but all exposed concrete will require some finish if even to just knock off the rough spots.Specs will define:Troweling, SOG, walks, stairs can be mechanical or by handFloat, SOG, walks, stairsBroom, mostly for walks & stairs

22

Sandblasting, exposes the aggregates, decorative walls, looks like pebbles on exteriorRubbed, with burlap & grout, creates a rough finish that looks like rough plaster used on decorative walls

Concrete Curing

Concrete gets it’s strength from the chemical reaction of water and cement, curing may be specified as 3-14 days depending on type and location.May need additional moisture to keep from cracking.Must be kept from freezing, by heating or insulation blankets. Some contracts may limit concrete placement to certain temperature requirements.If special heating or moisture requirements are needed the estimator must account for them.

Forms

Most concrete is poured in forms, sometimes can save $ by pouring “neat” eg use footers without forms, to save on forming material and time, but this method normally take more CY of concrete.Forms are estimated by SFCA, Square Feet of Contact Area. Calculate by LF x depth of form.Forms are made from :Wood, most versatile, needs to account for bracing, ties, wales etc, can get many uses out of wood forms if properly taken care of ( spray with oil and carefully taken off).Metal, mostly steel, normally lined with something. Normally used in larger construction projects, ie pans like roof in Hogue tech. Also used in residential construction I seen metal one for basements that leave a wall that looks like brick.

Wood

Actual dimensions are less than advertised due to milling process. E.g. 2”x4” (called nominal size) measure 1-1/2” x 3-1/2”.Lumber typically sold by mfbm (1000 Feet of Board Measure)or 1000board feet & estimating productivity tables use mfbm or cfbm (100fbm). Board feet is calculated using nominal board size.

Floor Framing

Handout pages 207-238Show overhead of picture on page 207Girder normally built up from smaller lumber eg 2 –2x12’s, or from manufactured beams made from laminated wood, I beams, composite wood. Estimated by simple measurement.

Sill, normally specs call for treated lumber, estimated by finding the perimeter of building.

Joist, normally 2x8, 10, or 12 spread 16”OC. Estimating steps are:1. From foundation & wall section find the size of floor joist.2. Find # of joist = # of spaces + 1. Eg 50’ long sill 16” OC 50’/16”/12”/1’=38spaces(round

up) + 1= 39 Joist.3. Multiply be # of bays4. Add one extra joist for each partition that runs parallel to joist.

23

5. Find board feet = # joist x joist size

Go thru example on page 210 & 211

Trimmers & Headers, special framing used for fireplaces, access doors, any holes thru floor. Trimmers run with the direction of the joist, headers run perpendicular to the joist.Estimated by:1. Sketch floor joist with out openings2. Sketch opening on joist3. Use available cuttings from hole & determine boards required. Double trimmers will be the

length of a joist & required for hoes >4’.

Joist header, show picture on page 211 & 216, estimated by LF of headers along perimeter.

Bridging, metal or wood cross racing. Metal is fastest to install, required every 8’. Wood is same size of joist, normally one bridging per bay.

Decking/ Subflooring, normally plywood, press board or waferboard. Sheet of plywood = SF coverage/ SF sheet +wasteShow figure page 218, mention nailing schedule (won’t have 2’ lengths when joist are 16”OC).

Wall Framing

Exterior WallsMost common residential is single bottom with double top plate combined with 8’ studs to produce 8’ ceiling (gyp board comes in 8’), see figure on page 220.Estimates Plates in mfbm= find perimeter LF x # of plates

Studs, typically 2x4, spaced 16” OC, may see 2x6 walls spaced 24” OC (why? Extra insulation)

Estimating Exterior Studs:1. Studs = LF perimeter/ spacing + 1 for last space2. Add studs for each corner 2 per corner, see figure page 2223. Add studs for framing wall openings, each window or opening will require at least 2 studs.4. Studs also required for gable ends of buildings, studs =

(gable length/ spacing +1) x Average gable height. Average gable height is 2/3 height of roof.

Headers, used to support the weight of the building above openings. Made from large lumber 4x10 or built up form 2x 10’s.Header length is opening with + 2(1.5), rest on 2x4’sEstimate headers by listing openings and adding up length, convert to mbfm

Wall sheathing, what goes on the exterior of buildings, normally two layers.1. Urethane insulation, or TYVEX type material2. Covering, wood (planks, T-111), AL, brick etc

24

Estimated by finding total SF required/ SF sheet (or material) If account for openings add waste or don’t account for openings. Also include sheathing for gable ends (area of 2 triangles) Need to check specs for sloped soffit (9’) or boxed soffit (8’), see figures on page 228 & 229.

Interior stud walls are estimated just like exterior but need to read the specs, may only be 24” OC, extra thick to hide chases.

Ceiling Assembly

Made from joist or trusses, depends on cost & if space will be sued as an attic space.Ceiling joist estimated same as floor:1. Size and spacing determined2. # of joist = length/ spacing + 13. Multiply # of joist by joist length, account for bridging and openings.

Roof Assembly

Rafters the hypotnuse of the triangle, need to account for the overhang. Normally spread 16” or 24” OC, made from 2x8,10,12’s.

Rafter length = (122+32)1/2 +1.5 = 10.87’ or 10’10”-3/8”Estimate rafters, Quantity of rafters should equal joist quantity, then multiply by length.

Collar ties boards to keep the rafters from separating, typically required every 3 rafters, 1/3 of the way down from the ridge, size is normally 2”x4”.Length is determined from similar triangles.

3/24=1/x, x = 24/3 = 6’Estimate collar ties = (rafters/3 +1) x length

Ridge board see figure page 236, normally 2x10 or 12, one size larger than the rafter, estimate is just LF of ridge

Lookouts, needed to frame soffit (note soffit not specified on “cheap” homes) see figure on page 236Estimate, # of lookouts = LF of each side wall/spacing +1), then multiply by, length of lookout.

25

24’

3’1.5’

24’

3’2’

Roof sheathing material, mostly exterior plywood plywoodEstimate Total SF/ SF sheet, note, must use rafter length.

Exterior Trim and Facias, many types, estimated by finding LF required.

Thermal and Moisture Protection

Handout pages 253-256

Insulation

Put in ceiling, walls and under floors to provide thermal protection. Rated in R value, higher the R the more insulation value of material. Home typically use rolls made to fit between the joist ie joist 16” OC will have 15” wide insulation, called “batt insulation”. Above ceiling may be blown, fiberglass.Estimating, find SF of area to be covered/ SF roll of insulation, be sure to use “effective coverage of roll. I.e.:Rolls = 1000SF/16”x56’(effective size of 15“ batt) = 14 rollsDo not account for openings or allow 5% waste.

Roofing

Roofs are estimated by the “square” = 100ft2.Asphalt Shingles are the most common for homes. Common sizes are strip shingles, 12 or 15” wide by 36 “ long. The exposed portion of a shingle is only about 4-5”. They are made in many colors, textures and thickness, with a “30 year shingle” better than most. Shingles are nailed to the plywood sheathing with large head galvanized nails. They have an underlayment of felt or “tar paper” normally 2 layers overlapped.Estimating, need to double singles at eaves, hips and ridges are taken off as LF & considered 1ft wide. Shingles, Squares = area of roof (in 100SF)+ eaves(in 100 SF)Ridge = LF of ridge/ inches of exposure per shingle = # shinglesFelt = Find roll coverage, (Width-lap)x (SF of roll) then SF of roof/ roll coverage. Round up # of rolls to a whole #.

Doors and Windows

For residential almost always wood framed and are stock ordered.

Windows

Estimated by developing a window schedule (table) or schedule is provided in specs.If subcontractor need to make sure all hardware is accounted for and who installs the windows. Estimate # of windows and calculate installation time.

Doors

Generally indoor (hollow) and exterior (solid). Residential door are almost always “pre hung” & specs need to be reviewed carefully because price varies considerably depending on veneer finish. Home typically have sliding glass doors or “French doors”. As with windows, door typically have a schedule that the type and #.

26

Finishes

All types drywall (sheet rock), plaster and lath, etc

Drywall

Or Gypsum board or sheet rock. Normally 4’ wide, by 8’,9’,10 or 12’ long. Thickness is normally ½” or 5/8”. Comes in various types, “green board” for use in bathrooms, fire rated and normal. Gyp board must be hung on studs or furred out from concrete/ block walls. It needs to be finished, e.g. taped, mud applied (joint compound), smoothed, and painted or wall paper applied. Must account for fasteners, screws or nails and trim to hide edges.Estimated by:1. Determine # of sheets required, LF/4’ +5% waste

Flooring

Home use mostly tile, wood, vinyl/ linoleum and carpeting.Resilient, or vinyl/ linoleum.Typically have underlayment of “luan” or particle board, need this to provide smooth surface. An adhesive is used to hold tile/ linoleum to floor. Estimated by the SF with consideration for waste.Carpeting. Comes in many sizes, colors and degrees of “quality”, e.g. thickness, pile fibers and weight. Carpet has an underlayment or cushion, sort of egg crate material made from rubber/ recycled materials, this material also comes in varying grades of quality. Carpeting is estimated by the SF.TileUsed on floors and walls. E.g. home entry way tile set in grout or color mortar. Also used to see this a lot in bathrooms, on floors and walls. Premounted on sheets is quickest to install. Tile is estimated by the SF.PaintingNormally estimated in area of actual SF. Interior and exterior. Specs will list coatings, color, and method i.e. spray or roller. Sequenced to be done after drywall before trim is applied.

Electrical

Almost always subcontracted out. Not always let to the lowest bidder. Can get SF cost based on type of construction to check subs bids. Electrical estimating requires each outlet and fixture be taken off and listed, also include quantities of wire in estimate.

Mechanical

Almost always subcontracted out. . Not always let to the lowest bidder.Plumbing is done similar to electrical, estimate all fixtures, lines, vents, etc.HVAC for residential construction is normally a heat pump, gas / oil furnace that blow hot air or heats water pipes.

27