After BillingAfter Billing KCTang Tue, 24/03/2020 - 01:11
24 Mar 2020: Separate pages on Editing, Finalising, Pre-tender Estimate and Tender Addendum merged into here. Clearing Drawings, Specification and Preambles, and Bulk checking added.
26 Dec 2014: Moved from wiki.
Editing by senior
- After a draft BQ has been prepared by the taking-off team, the draft BQ should be edited by the senior and experienced Surveyor who may be the team leader or a more senior Surveyor.
- The editing is to ensure sufficiency of descriptions, consistency in style and reasonableness in classification, logic in sequence, and appropriateness in itemization and units.
Ensuring appropriate P.C. rates
- The team leader or the editor should verify that the P.C. rates used are appropriate.
- After editing, corrections of the draft BQ should be made, and the corrected draft re-submitted for editing until satisfaction.
- Traditionally, the draft BQ described up to this point is in written draft form, the draft BQ should then be sent to the typists for typing. However, with the use of Excel or quantity take-off software, the draft BQ nowadays are usually typed by the taker-off when they take-off.
- The type setting must follow a specified format.
BQ production software
- Apart from spreadsheet software, there is a number of BQ production software based on manual or CAD or BIM entry which can integrate the measurement and billing processes. However, the processes described for editing and thereafter are still indispensable.
- Typed BQ or corrected BQ should be proof-read against the written draft or previously marked typed draft.
- The old drafts should be lined through to indicate that they have been corrected and proof-read.
Clearing Drawings, Specification and Preambles
- All the team members should sit together to check the Drawings, Specification and Preambles to see whether there are overlaps or omissions.
- General discussions should be conducted to verify the mutual scope of measurement.
- Drawings, Specification and Preambles should be checked for complete colouring, lining through and looping to ensure no missing items.
- The set of BQ Drawings should be identified. Members should initial on the set of BQ Drawings to signify that they have measured what they should have measured.
- A list should be kept of errors found and follow-up actions should be done to rectify.
- The list of BQ Drawings so identified should be used to compile the Schedule of Tender Drawings.
- The quantities measured should be checked for serious errors. However, it would be impracticable to double check every measurement dimensions. Furthermore, errors can arise in an unexpected manner in any stages of BQ production, e.g.:
- During taking-off
- During squaring
- During transferring
- During typing.
- Instead of checking the dimension sheets or taking-off schedules, it is better to check the quantities as stated in the typed draft BQ using independent but approximate methods.
- Quantities measured by a team member should be bulk-checked by another team member.
- A photocopy of the typed draft BQ should be used for bulk-checking.
- There are two modes of bulk-checking:
- Carrying out relative check by ratios between related items
- Carrying out absolute check by approximate measurement.
- If an item is correct by absolute check, then other related items which pass relative check based on the absolutely checked item can reasonably believed to be correct.
- In case of discrepancies between the draft BQ quantities and the bulk-check quantities, the first step is for the bulk-checker and the Taker-off to sit together to discuss their mutual scope of measurement and check, their approaches and assumptions to find out reasons for the discrepancies.
- If the explanation is not satisfactory, further check into the quantities will be required. The draft BQ quantities and the bulk-check quantities can be broken down into smaller portions, e.g. floor by floor, for identification of the possible location and source of discrepancies. If, say, a particular floor is found to create the discrepancies, only that floor will be checked further.
- Apart from checking the quantities, the bulk-checkers should also check to ensure the proper descriptions and appropriate units are being used.
- The first and the easiest and yet the most important check is to check the timesing.
- Timesing of a typical floor into the required number of floors and other similar timesing which have major multiplying effects should be carefully checked. The dimension sheets and taking-off schedules may be inspected for the timesing.
- Such check can usually avoid very serious errors.
Bulk-check formulae for concrete works, plastering, painting and roofing
- To carry out relative check, the relationship between different parts of the Works should be thought out and used for counter-check.
- The following are some formulae or equations for checking:
- Total covered floor area
> total concrete slab area
> total floor finishes etc.
- Total covered floor area
≈ Total concrete slab area + voids + lift shafts + staircases
- Base area of non-structural concrete walls and brickwalls
≈ (Concrete cube + brick area x thickness + window area x thickness of wall) ¸ general storey height
- Total concrete slab area
≈ Total floor finishes area + base area of non-structural concrete walls and brickwalls
- Total beam and slab formwork area > total ceiling finishes
- Total ground area = total roofing area + base area of parapets
- Total formwork area + 2 x brickwork (except those without finishes)
≈ total ceiling finishes + total wall finishes + total skirting area + internal sides of lift shafts + wall and beam sides above false ceilings
- Formwork to sloping soffit of staircase = finishes to sloping ceiling
- Length of nosing = length of risers (measure length of nosing on plan if nosing is not provided to all staircases)
- Formwork to riser = finishes to riser
- Plan area of treads = finishes to tread + nosing area
- Tile = screed area
- Plaster = paint area
- Total covered floor area
- Apart from its basic purpose, bulk-checking is also a useful process for training Surveyors to appreciate the relationship between different parts of the Works. Such appreciation would be useful for cost estimating.
Floor by floor analysis
- It would be useful to breakdown the quantities floor by floor so see whether there are relative consistency between the floor by floor quantities.
Bulk-checking concrete works
- A master schedule should be prepared to show the quantities of concrete, formwork and reinforcement broken down into elements of columns, walls, beams, slabs, etc. on a floor by floor basis.
- Ratios in the following forms should be calculated:
- concrete cube per floor area
- formwork area per floor area
- reinforcement weight per floor area
- formwork area per concrete cube
- reinforcement weight per concrete cube
- The ratios should be checked for consistency and reasonableness of variances between different elements and floors.
- It would not be practicable to check all reinforcement measurement in detail. Reinforcement is usually checked by:
- taking-off samples of concrete elements to obtain steel ratios to check against the steel ratios in the master schedule
- comparing with past similar projects to check the reasonableness of the steel ratios.
Comparing with estimate
- The bulk quantities in the draft BQ can be compared with the quantities in Preliminary Cost Estimate to see whether there are major deviations.
- Adjustments should also be made to complete measurement of missing items found when clearing Drawings, Specification and Preambles.
- Corrections should be made to rectify errors found in bulk-checking.
- Any changes to the draft BQ should be made using different coloured pencils so that the changes can be apparent.
- If changes are made directly on computer, either the results of the changes should be marked on the typed draft BQ used for bulk-checking or identifications should be made on the re-printed draft BQ.
- Any changes to the draft BQ should be seen by the bulk-checkers.
- If the bulk-checkers are satisfied with the accuracy of the BQ descriptions, units and quantities, they should initial against the quantities to signify acceptance.
- When all items have been initialled by the bulk-checkers, the bulk-checking process is finished.
- After making corrections and having them bulk-checked as well, the marked typed draft or re-printed draft with changes highlighted should be submitted to the editor again for final editing.
- If further changes are required, the preceding changes should be repeated.
Final typing corrections
- Finally edited and corrected written drafts can be submitted to typing corrections and reading over
- For manual measurement requiring transfer of quantities from bundles of dimension sheets to the written draft BQ, the quantities as typed on the final typed BQ should be compared with the quantities on the dimension sheets to ensure that all measured quantities are actually reflected in the final typed BQ. There may be chances that additional measurements have been made after the original written draft BQ, but they are forgotten to be reflected in the final draft and they have escaped the attention of bulk-checkers.
- To avoid fatigue, usually two persons are involved in reading quantities, with one reading out the quantities on one document and the other verifying the quantities on the other document.
- The units should also be read out as well to ensure that the correct units are typed.
- This process can be skipped if QTO software is used.
Contents sheet and thickness of documents
- Systematic page numbering should be adopted. Page numbers of various sections of the Tender Documents should be prefixed for easy identification purposes, for example, "PL" for Specification Preliminaries and "TS" for Technical Specification.
- The contents page should be compiled. Too thick a document may require to be split into two or more volumes and the covers should have volume number.
After final correction, the typed BQ can be submitted to photocopying.
- Checking should be done after photocopying to ensure no duplicate, missing, indistinct or defaced pages before binding.
- Random check can be done for highest quality service, otherwise full check should be done.
- Out-sourced printing companies may not check every page.
- In any case, the team leader should carry out random check on at least one sample.
- After page checking, the Tender Documents can be bound and dispatched to the Architects who would issue invitation letters to Tenderers to collect the Tender Documents for tendering.
As soon as the final BQ is ready and even before its dispatch to Tenderers, it would be a good practice and it may be a condition of service as well that the final BQ is priced to arrive at the expected tender price. The in-house priced BQ is called "Pre-tender Estimate" which is useful for:
- early identification of any major deviation from the previous Preliminary Cost Estimate
- comparison with prices returned by Tenderers.
- If major deviation between the Pre-tender Estimate and the previous Preliminary Cost Estimate is found, the reason should be identified. Care should be exercised to see whether it is due to errors in the BQ or errors in the previous Preliminary Cost Estimate, or due to design changes introduced after the previous Preliminary Cost Estimate. Errors in the BQ should be immediately corrected. Early notice to the Client should be made for major and true deviations between the Preliminary Cost Estimate and the Pre-tender Estimate.
Tender Addendum 修改通知
- It is very usual that tender addenda are required after dispatch of Tender Documents for tendering because of the need:
- to rectify errors found
- to complete outstanding measurement because of previous lack of information
- to update for lately revised Drawings or Specification.
- All the processes for producing the original BQ should be followed for making tender addenda.
- Amended or additional pages should have identifications such as:
- Using an asterisk "*" against the right hand side of the page number
- Using two or more asterisks or alternative symbols to signify the second or subsequent addenda
- Using the words "Tender Addendum No. X" at the top or bottom of the pages
- Using symbol against the left or right hand side or using other forms of highlighting to indicate amended or added BQ items.
- Some people use page number designated something like 3.2/1+1 or 3.2/1A to denote an additional page.