Dự toán xây dựng estimating in the construction industry, dự toán lắp dựng nhà gỗ

Learning Outcome: Prepare a takeoff for rough carpentry work. Learning Objectives: Define board measure units. Measure quantities of lumber in board measure units. Describe how wood framed floor systems and wall systems are measured. Describe how wood framed roof systems including wood trusses are measured. Describe how rough hardware is measured. ( 1 Pcs) Prepare a takeoff for rough carpentry and hardware for a house in accordance with rules of measurement and requirements of presentation.

• Measuring Carpentry Work

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Learning Outcome:

• Prepare a takeoff for rough carpentry work.

Learning Objectives:

1 Define board measure units.

2 Measure quantities of lumber in board measure units.

3 Describe how wood framed floor systems and wall systems are measured.

4 Describe how wood framed roof systems including wood trusses are measured.

5 Describe how rough hardware is measured ( 1 Pcs)

6 Prepare a takeoff for rough carpentry and hardware for a house in accordance with rules of measurement and requirements of presentation.

• In order to assess

rough carpentry

requirements, the

estimator has to be

familiar with framing

methods and be aware

of design requirements.

Measuring Rough Carpentry Work

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Board Measure

measured in LF then converted to BF for pricing.

Size) board 1-foot long.

thickness of the pieces in inches and divide the product by 12.

Board Measure

12 inch

1 inch One Board Foot =

Note …

We always use nominal dimensions

To calculate board measure or board foot

¾

11 ¼

The length is always expressed as the actual length

© 2016, Southern Alberta Institute of Technology

© 2016, Southern Alberta Institute of Technology

Rough carpentry work – Measuring Notes

1 Lumber is measured in linear metres or board measure.

2 Lumber generally shall be differentiated and measured separately on the basis of:

3 Lumber required to have special treatment (e.g., pressure treated), must be kept separate and described.

4 Wall boards shall be measured in square metres (or square feet).

6 Wall boards are classified and measured separately, in type of material and thickness.

Rough Carpentry Work – Measuring Notes

1 Lumber is measured in linear metres or board measure.

2 Lumber generally shall be differentiated and measured separately on the basis of: dimensions, dressing, grade and species, etc.

3 Lumber required to have special treatment (e.g., pressure treated), must

be kept separate and described.

4 Wall boards shall be measured in square metres (or square feet).

5 No deductions are made for openings less than 4 square metres ( DDT Limit 4 m2)

6 Wall boards are classified and measured separately, in type of material

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Rough Carpentry Work – Measuring Notes

c) Joists j) Hip and valley rafters

d) Bridging k) Lookouts and overhangs (Eaves)

e) Lintels l) Gussets and scabs

f) Solid beams m) Purlins

g) Built-up beam n) Other framing items not listed

Rough Carpentry Takeoff … Floor System

• Steel Posts

• Built up Beam or Parallam/Microlam beam or 2 x 10 ,12

• Floor Joists … Divide width of the floor by 400mm round up

then add one, also add one on each side of the stairwell

• Floor system is completed with a rim joist around the perimeter

of the house

• Floor Sheathing … Deduct any openings greater than 4 m2

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Rough Carpentry Takeoff … Floor System

Rough Carpentry Takeoff … Floor System

© 2016, Southern Alberta Institute of Technology

Rough Carpentry Takeoff … Floor System

Rough Carpentry Takeoff … Floor System

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Rough Carpentry Takeoff … Floor System

Rough Carpentry Takeoff … Exterior Walls

• Exterior walls … Perimeter length

• Plates x 3

• Studs /.4

• Lintels or headers greater than 600 mm,2ply ( 38 x 235 )

length of lintel = RO + 2 x 38 mm for 2 trimmers

• Exterior wall sheathing … We do not deduct for windows and

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Rough Carpentry Takeoff … Exterior Walls

Rough Carpentry Takeoff … Exterior Walls

© 2016, Southern Alberta Institute of Technology

Rough Carpentry Takeoff … Exterior Walls

WIDEC is a memory tool used for counting the extra studs required during framing.

◦ W indows – 4 Extra Studs

◦ I ntersections – 2 Extra Studs (In the Wall with the larger studs)

◦ D oors – 2 Extra Studs

◦ E nds – 1 Extra Stud (interior walls only)

◦ C orners – 2 Extra Studs

© 2016, Southern Alberta Institute of Technology

Rough Carpentry Takeoff … Interior Walls

• Interior walls … each wall one at a time … Use highlighters

to keep track of your takeoff

• Plates x 3

• Plates for partitions are measured through door openings

• A quick way to takeoff the studs for interior partitions is to allow

a Studs for every 300mm

Roof Framing

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Roof Framing

Floor Framing

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Floor Framing

Roof Framing

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Roof Trusses

Attic Trusses

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Rough Carpentry Work – Measuring Notes

Trusses and Truss Joists and Truss Rafters:

• Prefabricated trusses, truss joists and truss rafters are to be enumerated and fully described.

Manufactured Beams, Joists and Rafters:

• Manufactured beams, joists and rafters are to be measured in lineal

metres and fully described.

Roof Calculations

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Rough Carpentry Takeoff … Roof System

• Number of trusses required = length of the building divided by

the truss spacing.

• Ridge blocking = length of building + overhangs

• Barge Rafter = length of roof slope

Rough Carpentry Takeoff … Roof System

© 2016, Southern Alberta Institute of Technology

Rough Carpentry Takeoff … Roof System

Rough Carpentry Takeoff … Roof System

© 2016, Southern Alberta Institute of Technology

Rough Carpentry Work – Measuring Notes

Sheathing:

• Sheathing is measured in square metres; wall, floor and roof sheathing is to be described and measured separately.

• Diagonal work is kept separate.

• Common boards, ship-lap, tongued and grooved, plywood and other types of sheathing are measured separately.

• Work to sloping surfaces is described and measured

separately.

Rough Carpentry Work – Measuring Notes

Copings, Cant strips, Fascias, etc.:

 Copings, Cant strips, Fascias, etc are measured in linear

© 2016, Southern Alberta Institute of Technology

Rough Carpentry Work – Measuring Notes

Vapour Barriers and Air Barriers:

• Vapour barriers and air barriers are measured in square metres, describing the type of material used.

Underlay and Subfloors:

 Underlay and subfloors are measured in square metres, stating the type of material used.

Rough Carpentry Work – Measuring Notes

Blocking, Furring, etc.:

categories:

a) Blocking stating purpose and location

b) Furring stating purpose and location

© 2016, Southern Alberta Institute of Technology

o QUESTIONS?

o Next, measure SHAW House – rough carpentry section in class together.

o LONDON to be Assignment # 3

Mod 10:

Introduction

Examine the goals of the estimating process Overview of how the construction industry operates and introduce preliminary

estimating techniques.

So… what is ESTIMATING?

◦ an approximation of cost

◦ an evaluation of the future cost to complete the project before any work starts.

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Definitions Review

Project Stakeholders:

• Owner / Developer

◦ Initiates & Finances the Project

• Architect/Designer/Engineer (a.k.a Design Team)

◦ In charge of the vision and design

• Contractor / Construction Manager

◦ Manages the building process, trades, and/or builds the project.

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◦ Ideas, sketches, preliminary design, design development, working

drawings, tender sets, issued for construction, etc…

• Tendering Phase

◦ “Issued for Tender” (IFT) Drawings are provided to construction companies

to prepare “Estimates” to complete the construction of the project

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Definitions Review

Phases of a project:

• Construction Phase

◦ Site grading, excavation & backfill, concrete, rough carpentry, mechanical

& electrical, finish carpentry, finishes, etc…

• Commissioning / Occupancy Phase

◦ Development is occupied or commissioned by owner

Role of Estimating

3 Main Types of estimates that each serve different functions

within the construction industry.

1 Conceptual Estimates:

 Prepared during the Planning Phase of a project

 Estimate of the probable cost of the work to determine feasibility of the project

 No design details available at this time

2 Preliminary Estimates

 Prepared during the Design Phase

 Typically part of cost control programs that help manage expenditure of funds throughout a project

3 Detailed Estimates

© 2016, Southern Alberta Institute of Technology

CONCEPTUAL ESTIMATES

Go or No-Go?

• An owners decision to proceed with a project is based on a comparison of

2 key factors:

◦ Value – determined by the owner

 Return on Investment (ROI)

 Public Benefit

 Public Image

◦ Cost – estimated by a conceptual estimate

 Design and Project Management costs

◦ ex: sale price of $6M > development costs of $5M = feasible project

The owner relies on a Conceptual Estimate

to quantify these costs.

PRELIMINARY ESTIMATES

Preliminary Estimates are prepared throughout the design process to help the design team ensure their design meets the project budget.

◦ Prepared at specified intervals

 Ex 25%, 50%, 75% of design completion

◦ Often subdivided into common price categories specified in the cost plan for the project.

 Substructure, Superstructure, Cladding, Flooring, Stairs & Lifts, etc…

◦ Prepared with incomplete design details

 Accuracy of preliminary estimates increases as design progresses and details are finalized.

◦ Allows design team to make design choices to stay on budget

 Alternatives are continually evaluated to ensure the most appropriate selections are made to accomplish the owners and designers objectives.

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Unit Price

• Project is analyzed in terms of the number of items of a certain unit

◦ ex: number of rooms in a hotel

• Unit Price = Total Construction Cost / Number of Rooms

• Why estimate based # of units?

◦ Owners revenue comes from the cost per night for the hotel room

◦ Owner needs to know how long will it take to pay off the project based on projected occupancy

 i.e $200/night/room x 100 rooms = $20,000 revenue/night (if full)

• Unit pricing from one project can be used to forecast future projects.

◦ Note: Projects must be similar in nature for unit cost forecasting to be accurate

 i.e - construction design, overall size, quality of finish, geographical location and the time of year for construction.

© 2016, Southern Alberta Institute of Technology

Area Price

• The most common method of preliminary estimate

• The cost per square meter (m2) or square foot (sqft) of a project is determined by dividing the construction costs by the gross floor area.

• Area Price = Total Construction Costs / Gross Floor Area

• Gross Floor Area (GFA)

◦ Area of all floors measured to the outside of the exterior walls

◦ Does not include:

 area of a basement (finished or unfinished)

 area of an attached garage

 areas of exterior stairs, balconies or any other exterior projections outside the face

of exterior walls

 Areas of openings in floors for stairwells or elevator shafts

Area Price

Determine the Area Price for the following examples:

• A 1400 sqft house built for $90,000

• A 12740 m2 warehouse built for $2.43 million

• A 15 storey apartment building built for $45 Million

◦ 15 floors above ground

◦ 4 floor underground parking garage beneath building

◦ 6100 total sqft per floor

◦ 2 elevator shafts (50 sqft each) extend from the top floor to bottom of parking garage

© 2016, Southern Alberta Institute of Technology

Volume Price

• Similar to Price per Area, however project is determined by dividing the construction costs by the gross volume of a building

• Volume Price = Total Construction Cost / Volume of Building

Volume = height of building x area of the building Height = bottom of gravel below basement to top of roof surface

• Commonly used for estimating warehouses with high ceiling heights.

◦ Higher ceilings result in greater skin area, therefore an area price is often not appropriate

Approximate Quantities

• Accounts for both the overall project size and the prices of

specific resources used in construction:

◦ Design details, quality of finish, geographical location and time of year when the work was undertaken

• It is done by measuring and pricing assemblies of work that comprise a group of related trade activities.

◦ Approximately how much concrete will be used

◦ Approximately how much electrical work is required

◦ Approximately how much drywall and finishing is required

◦ Approximately how much site grading is required

© 2016, Southern Alberta Institute of Technology

OBJECTIVES OF AN ESTIMATING

DEPARTMENT

Planning Phase: Owner requires Conceptual Estimate to

determine if project is GO or NO-GO

Design Phase: Drawings developed to confirm the

scope of work Preliminary Estimates are required to

refine the accuracy of the cost plan budget.

Pre-bid phase: Specifications and final drawings are issued Pre-Bid Estimate is prepared for owner.

Tendering phase: Bidders prepare Detailed Estimates to price the job The contract is award based on the

tender selection criteria pre-established

Construction phase: Construction work takes place Cost Control Estimates are required Change orders are issued during construction.

STEPS in the ESTIMATING PROCESS

Pre-Estimate Steps Gather Bid Information Review Bid Documents Decide to Bid or Not

Module 11:

The Estimating Process & Preliminary Procedures

• This module describes the estimating process and provides the basic framework for the modules that follow You will use the skills acquired here in many subsequent sections

• This module introduces the process of estimating and will help you develop your skills in measuring drawings and calculating building

perimeters

• 11.1 Explain the purpose of conceptual and other preliminary

estimates

• 11.2 Describe five methods of preparing preliminary estimates

• 11.3 Given the floor plan of a residential building, compile a

preliminary estimate using the cost-per-unit area method

• 11.4 Given the external or internal dimensions of a perimeter wall, calculate the length of the centreline perimeter

STEPS IN THE ESTIMATING PROCESS FOR A PROJECT

DEFINITION OF A “QUERY LIST”

• List of all questions from the estimator to the designer during the quantity take-off process, instead of several phone calls

• Designers will respond orally to the estimators regarding minor

questions

• Written responses are required for significant questions, known as addenda or bid bulletins These documents become part of the tender documents and must be included in both the Bid and the Contract with the awarded contractor

In our Class: Assignment Questions should be addressed using this approach to get use to the process and industry norms

DEFINITION OF “TEAM APPROACH”

• During the estimating process, the estimator usually works alone on quantity and cost estimates

• A better result can be obtained with the involvement of managers and experienced field personnel

• Some companies establish an estimate review meeting a couple of

days before the bid due date The purpose of the meeting is to involve company managers and estimators to review the estimating prices and assumptions made in the preparation of the estimate