T6. QUANTITIFCATION & COSTING OF CONSTRUCTION WORKS Flashcards
Why were the New Rules of Measurement introduced?
- SMM7 was designed for the production of bill of quantities for tender purposes.
- NRM was introduced to provide a common and consistent basis for the production of order of cost estimates and cost plans.
What is the structure of the NRM 1?
The key sections of NRM1 are:
* Part 1: General introduction explaining the purpose of the document and how it should be used.
* Part 2: Measurement rules for the production of order of cost estimates.
* Part 3: Measurement rules for the production of elemental cost plans.
* Part 4: Tabulated rules of measurement for elemental cost planning.
* Appendices: With references to the definitions for GIA, functional units, NIA, elemental breakdowns, templates and general information required for cost plan production.
Why should you use the New Rules of Measurement?
- The NRM provides a common and consistent basis for the production of order of cost estimates and cost plans.
- In the event that a QS or firm is pursued for negligence, the use of NRM would provide a means of defence as it represents best practice.
- Colleagues can pick up an estimate and understand the basis of calculations.
What are the NRM 1?
- The RICS New Rules of Measurement 1 is the Order of Cost Estimating and Elemental Cost Planning.
- This provides a structured basis for measuring building works and for the production of Cost Estimates and Cost Plans.
What is meant by the abbreviation GEA?
- Gross External Area.
- This is the area of the building measured externally at each floor level.
- Used in town planning and residential insurance
What is meant by the abbreviation GIA?
- Gross Internal Area.
- This is the area of the building measured to the internal face of the perimeter wall at each floor level.
- The GIA excludes external open sided balconies, fire escapes, canopies, external walls and fuel stores.
- Used for building cost estimation
What is meant by the abbreviation NIA?
- Net Internal Area.
- This is the area of usable space measured to the internal face of the perimeter wall at each floor level.
- The NIA excludes internal structural walls and columns, spaces with headroom less than 1.5m, permanent lift lobbies, toilets, cleaners’ cupboards and plant rooms.
- Used for estate agency and valuation calculations for offices and the like.
Where are all of these abbreviations defined?
- The RICS Code of Measuring Practice (6th Edition) 2015.
(To be superseded by IPMS all buildings)
What is the purpose of the Code of Measuring Practice?
- The Code of Measuring Practice provides precise definitions to permit the accurate and consistent measurement of buildings.
What would you expect the percentage of NIA to GIA to be?
- The percentage would depend on the type of project being undertaken for example whether this was a school, hospital or office.
- In the case of an office building, I would expect the NIA to GIA percentage to be in the region of 70-85%.
- Where 70% is considered as relatively inefficient, a percentage of 85% is extremely efficient.
What do you measure in accordance with?
- Typically the New Rules Measurement, but understand this depends on region/discipline
What is the purpose of a BoQ?
- Provide a contractor with an accurate picture of the scope of works.
- Provide a common and consistent basis for pricing.
- Form basis of tender analysis.
- Provide basis for valuations and change control.
How would you prepare a BoQ?
- I would obtain the complete design information including drawings, spec, schedules etc.
- I would agree with the client the method of measurement to be adopted.
- Prior to commencement of measurement and taking off quantities, I would consider the size of the Project and break the works down into sections and areas for example:-
o Substructure.
o Superstructure.
o External Works. - I would then commence take-off & work in a logical sequence following NRM
- Once measuring is complete I would look to address the general items section & any preambles.
How would you structure a BoQ?
In accordance with an elemental breakdown structure under NRM 2, I would include the following
sections:
* Preliminaries (Main Contract).
* Facilitating Works.
* Substructure.
* Superstructure.
* Internal Finishes.
* Fittings, Furnishings and Equipment.
* Services.
* External Works.
* Provisional Sums.
* Dayworks.
How would you describe the preliminaries section in a Bill of Quantities?
The preliminaries detail items of work that are required to enable the construction but are not associated within the permanent measured works items, such as:-
* Site setup.
* Management & supervision.
* Insurances for the project.
* Task Lighting.
* Protections and temporary barriers.
What information is required to measure preliminaries?
- Contract duration.
- Location.
- Type of project (New Build vs. Refurb).
- The size of the project.
- Temporary works.
- Security.
- Methodology.
- Programme.
- Services.
- Employers accommodation.
- Contractor designed work.
- Sectional completion.
- Insurances / Bonds.
If it was found that a Bill rate was blatantly wrong for example £100 was included as a rate instead of £1, how would this be resolved?
- The works would be valued in accordance with the agreed rate contained within the contract.
- If identified within the tender documents prior to the contract being agreed then the rate could be amended in accordance with the Tendering rules in place, but otherwise both parties would have to stand by the rate.
How do you evaluate a variation which is based on a BQ item which contains an error?
- Assuming the same nature & conditions are applicable, the variation would be based on the BoQ rate within the contract.
- Unless both parties agreed to amend the rate to one that is fair and reasonable.
Who owns the copyright to a BQ?
- The originator owns the copyright.
- This is the QS generally who provides the client permission to use the document for its intended purpose.
How would you deal with a situation where it was discovered a part of a BQ was missing after the Main Contractor was on site?
- If part of the BQ was missing then I would check to see if it were included as part of the tender documents & ultimately the contract sum.
- If not then the ultimate responsibility would lie with the Employer.
- Providing the works were still required by the Employer they would be treated as a variation to the contract.
- I would request that the contractor price the works & advise the Employer on the level of costs involved before the instruction is issued.
What would you include within the BoQ where works are to be carried out by Nominated Subcontractor?
A prime cost sum would be incorporated including:
* An allowance for the cost of the Nominated Subcontractors work (based on the quotation).
* An allowance for the contractor to price for attendances such as accommodation, welfare, storage, handling, materials & cleaning.
* An allowance for a percentage addition for any other charges & profit.
What is a Provisional Sum?
- A Provisional Sum is an allowance included within the BQ for works to be carried out where the extent and design of the work is not yet know meaning the cost cannot be established at the time of agreeing the contract sum.
- This could include works by a nominated subcontractor or supplier, or a statutory authority.
What is the difference between defined and undefined provisional sums?
- A defined provisional sum is one that relates to works that cannot be accurately measured, but there is sufficient information about the works including their nature, method, location, quantity, limitations to allow planning, programming & pricing of preliminaries to take place. The contractor would therefore only be entitled to claim for any increase in the cost of the physical works.
- Where there is insufficient information, the works are classed under an undefined provisional sum
entitling the contractor to costs for prelims and an extension to the programme.
How would you undertake an audit on a cost reimbursable contract?
- Upon submission of the application by the contractor I would ensure this is provided in the agreed format & detail.
- I would review all the costs incurred to date in respect of Labour Plant & Materials, Staff & OH&P.
- I would carry out an audit of the information & reconcile this against the fee schedules & rates within the contract.
- I would check timesheets, staff grades & rates, project codes, payroll burden, invoices, subcontract accounts, applications & payments, materials invoices, dates, rates, quants, delivery tickets etc.
- This would be compared against the contract rates to enable any adjustments that may be needed.
How did you check that the items measured for the BoQ were accurate?
- We have an internal peer review system where upon completion, a joint review of the drawings is carried out by my senior colleagues to ensure all scope of work items are captured.
- Junior colleagues assist with undertaking spot checks on the quantities to ensure these are accurate.
What items would you include for when measuring for example a basement?
- It would depend on how the basement would be constructed.
- When measuring a basement with piled walls and assuming the site was clear I would measure:
o Excavation & dispose of topsoil.
o Continuous piles to walls including the piling rig, hard standing piling mat, testing, cutting &
prep heads.
o Excavation & disposal of arisings.
o Preparation of the excavated surface.
o Waterproofing.
o Blinding.
o Concrete to the basement slab & walls.
o Reinforcement.
o Formwork to walls.
o Finishes to concrete.
o Internal finishes.
How are obstructions dealt with on site? And in which package do you see them included?
- Obstructions are normally dealt with by a Provisional Sum within the Bill of Quants, due to the undetermined nature of the works.
- They would usually be included in the earthwork’s contractors’ package, responsible for excavating the foundations.
How do you measure cut and fill?
- I would obtain drawings with existing levels & proposed levels.
- I would divide the area of excavation into a grid & interpolate the levels on the grid to establish an average existing & proposed level.
- This would determine which area was in cut and which area was in fill.
Is the quantity for excavation similar as disposal?
- Yes providing there is no backfilling required and assuming the form of contract and method of
measurement does not allow for bulking, shrinkage or waste of earthworks.
How would your approach to measurement change if you worked in Dubai
- I would need to measure in accordance with the method of measurement appropriate for that country.
How do you measure something unique for example a statue of the client?
- If it could be broken down easily into the parts that are in accordance with the method of measurement, I would use this as the basis for measurement.
- Otherwise I would have to insert an item with a detailed description of the works with a section to include a Provisional Sum.
How do you deal with ground water under NRM2?
- Ground water is measured under Section 6 ‘Ground remediation and soil stabilisation’.
- It is measured on an itemised basis.
- The method and place of discharge is left to the discretion of the contractor unless stated otherwise.
What is a Preamble?
- A preamble is an explanation of a document that is commonly found in contracts, specifications and bills of quantities.
- It can help with the interpretation of the document.
- It includes a description of the parties to the contract.
- The background to the document.
- Measurement procedures that have been adopted.
What are time related charges?
- Time related charges are method related charges that are considered proportional to time taken to carry out the works for example plant hire.
What are fixed charges?
- Fixed charges are method related charges that do not vary with time for example Service Connection Charges.
What sources of pricing data are you aware of?
- Historical/in house data
- Published data (SPONS/BCIS)
What are the advantages of pricing books?
- Easily accessable
What are the advantages of in-house cost data?
- The QS has detailed knowledge of the conditions in which the work was undertaken.
- Can be more reliable
What are the disadvantages of pricing books?
- Rates can be generic and not consider individual project characteristics
What are the disadvantages of in-house cost data?
- Limited Dataset – Only based on internal projects, lacking wider market trends.
- Resource Intensive – Requires time and effort to collect, update, and standardise.
- Variability – Differences in project scope, location, and methodology can impact reliability.
What are the various types of pricing documents used at tender stage?
- BOQ’s
- Activity Schedule
- CSA
When would you use a BOQ?
- Traditionally procured contracts whereby design is sufficiently developed.
- Under an Option B to show the total of the prices and for interim applications.
- Under an Option D to show the total of the prices only
When would you use a priced activity schedule under NEC?
- Under an Option A to show the total of the prices and for interim applications.
- Under an Option C to show the total of the prices only
When would you use a CSA?
- Typically used as pricing documents on D&B projects to analyse tender returns and as basis for AFP’s.
What is the BCIS?
- The BCIS provides construction cost and price information through publications, online services and price books.
How would you utilise the BCIS to adjust cost data for inflation?
- Identify the Base and Target Dates.
- Obtain the BCIS Tender Price Index (TPI) or PUBSEC.
- Apply the Adjustment Formula.
How would you utilise the BCIS to adjust cost data for location?
- Identify location of Base data
- Obtain BCIS Location Factor – Use BCIS Regional Location Factors.
- Apply the Adjustment Formula
What method of measurement would you use to prepare an Order of Cost Estimate?
- Floor Area Method
- Functional Unit Method
- Elemental Method
What method of measurement would you use to prepare an Cost Plan?
- Elemental Method
What is a pre-tender estimate?
- The pre-tender estimate (PTE) is the final estimate of the likely cost of works based on the completed tender documents before inviting tenders from prospective suppliers.
How would you use a priced activity schedule to assess a contractors payment application?
- Attended site to inspect the works.
- Scrutinised the contractor’s activity schedule against progress.
- Ensured only 100% completed activities were included in my assessment to the PM
When would you adopt the cost per m2 method when preparing an order of cost estimate?
- When floor area is known but design is not detailed enough to measure building elements.
When would you adopt the cost per functional unit method when preparing an order of cost estimate?
- When Clients brief is clear on nr of functional units required but floor area may not be known and design is not detailed enough to measure building elements.
When would you adopt the elemental method when preparing an order of cost estimate?
- Where the design information is detailed enough to measure some of the elements separately elements of the build separately.
What is NRM2?
- New Rules of Measurement for detailed measurement of building works
What is the purpose of having a standard method of measurement?
- Ensures consistency and uniformity in measurement.
- Improves clarity and understanding across all project stakeholders.
What is GIA?
- Gross Internal Area: The floor area of a building measured to the internal face of the perimeter wall at each floor level. Includes stairwells, lift cores, risers and areas occupied by internal walls.
What is GEA?
- Gross External Area: The area of a building measured externally at each floor level. Excludes open-sided balconies etc.
What is NIA?
- Gross Internal Area: The useable floor area of a building measured to the internal face of the perimeter wall at each floor level. Excludes stairwells, lift cores, risers and areas occupied by internal walls or structures.
What is GIA typically used for?
- Building cost estimation
What is GEA typically used for?
- Town planning
- Building insurance cost estimation
What is NIA typically used for?
- Estate agency and property valuation.
What are the different pricing documents used at tender stage?
- Bill of Quantities (BOQ).
- Contract Sum Analysis (CSA).
- Schedule of Works.
- Activity Schedule.
When might you use a CSA?
- Commonly used in Design & Build contracts to provide basis for comparison of tender returns.
When might you use a BOQ?
- In traditional procurement when detailed design information is available.
- When using NEC Option B or D contracts.
How is cost data adjusted for location?
- Using BCIS location factors.
How is cost data adjusted for inflation?
- Using BCIS Tender Price Index (TPI) or PUBSEC non-private housing indices.
How do you go about preparing a pre-tender estimate on a project?
- Use the pricing document issued at tender stage.
- Utilise historical in-house cost data to estimate costs for each element and adjust for location/inflation as necessary.
How do you go about producing a CSA?
- Review the drawings and NRM2.
- Take a structured approach, following the tabulated measurement rules.
- Ensure descriptions are as detailed as the design information allows.
How did you assess the contractors application on Project Ward 7 South?
- Attended site to inspect the works.
- Scrutinised the contractor’s activity schedule against progress.
- Ensured only 100% completed activities were included in my assessment to the PM.
- Removed disallowed costs as necessary.
- No retention was necessary (Framework Agreement).
- Deduct previous payments made.
How do you assess costs for construction variations on JCT Projects?
- If works are of a similar character in similar conditions, use contract rates.
- If works differ in character, agree fair and reasonable rates with the contractor.
- If works are of a similar character but under different conditions, adjust rates accordingly.
How do you assess costs for construction variations on NEC Projects?
- Assess the actual cost incurred up to the dividing date.
- Forecast the remaining cost from the dividing date.
How did you advise on the most appropriate methods of costing variations on Project Barnet Infill Phase 2?
- I advised the client that the works were of similar character and undertaken under similar conditions to those in the contract, so contract rates should be used.
How did you produce the pricing document in accordance with NRM2?
- I followed the NRM2 tabulated rules of measurement to ensure a structured and methodical approach to quantification.
In what instances would you accept a unit rate that was different to those within the contract?
- If the works were not of a similar character to those in the contract.
In what circumstances would dayworks be acceptable?
- When work cannot be priced in the normal way, such as unforeseen or reactive works.
What are star rates?
- Rates not included in the original contract, used to price variations or work not covered by standard contract rates.
When would star rates be applicable?
- When variations involve works that are not of a similar character to those in the contract.
On Project Ward 7 South, why did you recommend the floor area method over, say, the functional unit method?
- As it was a refurbishment of an existing ward, the site boundary and floor area were known, providing the most accurate basis for the OCE. The number of functional units was not clearly defined.
On Project PPU, why did you recommend an elemental cost estimate was carried out over the floor area/functional unit method?
- The architect had produced drawings with sufficient detail to support a high-level elemental cost estimate.
