Model Preamble for BOQs

Model Preambles for Trades

• BOQs allow contractors to price items consistently across the entire contract, ensuring fair comparisons, but this is reliant on clear and accurate descriptions.
• The descriptions need to be concise yet comprehensive enough for various contractors to interpret them uniformly.
• Quantity Surveyors use preambles to avoid overly long descriptions, resulting in unwieldy BOQs.
• Preambles are short descriptions of items common to most buildings.
• Model Preambles for Trades is a compilation of such descriptions.
• A preamble serves as a preface or introduction in a BOQ, providing additional detail for each trade.
• Model Preambles exist for reference, in place of repeating specific information in every BOQ.

Model Preambles

• Model Preambles ensure material and workmanship quality through standardization.
• In the absence of Model Preambles, contractors would have varying interpretations of construction specifications.
• Using standard documentation in Model Preambles produces economic advantages for contractors/professionals.
• Model Preambles reduce disputes through shared awareness and adherence to document.
• They simplify tendering and administration in building contracts.

Supplementary Preambles

• When a client has specific needs differing from Model Preambles, Supplementary Preambles are included in the trade introduction.
• Supplementary Preambles supersede Model Preambles, and BOQ descriptions overrule Supplementary Preambles.

Preliminaries - Definition

• The "Preliminaries" bill is typically the initial bill in a "Bill of Quantities".
• Before JBCC agreements, "Preliminaries" were termed "Preliminaries and General" items ("P & G's").
• "Preliminaries" sets out the contract's administration and describes factors affecting the contractor's staff, equipment and work execution on site.
• The Association of South African Quantity Surveyors (ASAQS) created a 'Preliminaries' document (November 2007) for JBCC Series 2000 contract documents.
• This document aims to standardize documentation and improve building industry practices.
• Standard documentation reduces time spent drafting "preliminaries" for each "Bill of Quantities".
• This standardization should give contractors more confidence, and reduce disputes.

Preliminaries - Document Use

• The document "Preliminaries" is part of building and subcontract documentation.
• The "Preliminaries" document, similar to the "Principal Building Agreement," is bound separately.
• Contractors should account for potential costs from complying with this "Preliminaries" document.
• The "Preliminaries" document is for reference only and is not reproduced in the “Bill of Quantities".
• Contractors must obtain their own copy of the "Preliminaries" document.
• Contractors need to study and familiarize themselves with the document content when preparing tenders.

Preliminaries - Structure

• "Preliminaries" for projects are divided into three sections.
• Section A aligns with headings of JBCC Principal Building Agreement clauses, ordering these clauses as they appear in the agreement.
• Some JBCC clauses require pricing, while others don't have financial implications for the contractor.
• "Contractors representative" will require pricing.
• Contractors calculate costs for having a representative on-site during the full contract.
• Section B mirrors the order of headings in the ASAQS "Preliminaries" document.
• Section C includes special items not in Sections A or B such as unique requirements.
• This gives contractors opportunity to price compliance.

Standard System of Measuring Building Work

• The Standard System of Measuring Building Work 2015 (7th edition) is compiled by the "Standard System Joint Committee”.
• Committee include all the role players in the building industry.
• The document is published by the Association of South African Quantity Surveyors.
• In 1906, the first standard system for measuring building works in South Africa was published.
• The original system was created to reach consensus between contractors and quantity surveyors on how to measure building works.

Standard System - Composition and Contents

• The Standard System is divided into trades, with the order matching the trades' sequence in the "Standard System".
• Initial studies focus on trades relevant to simple single-story residential and commercial building projects.
• These focus topics are:
  • General instructions
  • Preliminaries
  • Earthworks
  • Concrete, Formwork and Reinforcement
  • Masonry
  • Waterproofing
  • Roof coverings
  • Carpentry and joinery
  • Ceilings, Partitions and Access flooring
  • Floor coverings, Wall linings, etc.
  • Ironmongery
  • Plastering
  • Tiling
  • Glazing
  • Paintwork
• The "Bill of Quantities" specifies work shown in drawings or specifications.
• Measured work is arranged according to the "General Instruction No. 4 page 3 of the 'Standard System’".
• The "Trades" rule divides work into specific trades.
• Ancillary work applicable to a trade is included in that trade following established principles.
• Within a trade, items are ordered first by mass (kg or tons), then volume (m³), area (m²), length (m), and finally by number.
• Works that cannot be placed into one of the unit measurements above are added as an "item:.
• Items are placed in order of relative value (cheapest to most expensive).
• There are exceptions to every rule.

Net Measurements

• "Bill of Quantities" primarily uses "whole" numbers.
• If a measurement is 33.67m², it is recorded as 34m² in the bill.
• Quantities are rarely given to decimal places.
• Values below 0.5 are rounded down, equal to 0.5 and above are rounded up to the next whole number.

Fractional Quantities

• While quantities are generally rounded, small quantities are expressed to one decimal place.
• The reason is that when rounded down the quantity could disappear altogether.

Provisional Quantities

• If the quantity cannot be determined when preparing the "Bill of Quantities," the work is labeled “provisional".
• Provisional quantities are measured according to available data during the initial "take-off".
• Final quantities are determined by remeasurement after the work is completed.
• The work associated with "FOUNDATIONS” is provisionally measured.
• "Foundations" include all work below the surface bed such as:
  • Excavations
  • Risk of collapse
  • Backfilling
  • Concrete in footing
  • Foundation brickwork
• Measurements are taken to the top of the surface bed.
• The "Bill of Quantities" measurements are extracted the drawings and sections.
• Contractors may encounter unexpected ground conditions when excavating.
• They may encounter unsuitable soil, rock, clay, or high water tables.
• These conditions are hard to gauge accurately without excavation.
• Trial holes offer an indication only in specific locations.

Implications of Unexpected Ground

• Deep excavations mean handling more material (additional backfilling).
• Risk of collapse increases.
• Fair compensation involves on-site measurements after excavation.
• New quantities are calculated and valued using original rates provided in the priced "Bill of Quantities."

Provisional Sums

• Provisional Sums: Money included in the Bill of Quantities by the Quantity Surveyor for specialist sub-contract work (plumbing or electrical).
• Insufficient information to measure work, or if a specialist work is not designed yet, at time of take off.
• The Quantity Surveyor includes a monetary amount when it is known work will be required.
• Every "Provisional Sum" contains two extra items: “Allow for Profit" and "Allow for attendance on the sub-contractor".
• “Allow for Profit" allows contractors to add any profit they would want included on the specialist sub-contract work.
• Main contract could add the profit to markup.
• If a contractor adds too much profit, they risk losing the entire bid.
• "Allow for attendance on the sub-contractor”, is given to account for any costs associated with the sub-contractor carrying out the work.

Prime Cost Amounts (P.C. Amounts)

• Prime Cost Amounts are included in Bills of Quantities to establish an allowance for a set of quality materials, when the final price is unknown.
• It allows to supply materials only.
• The prime cost amounts is followed by two items:
  • "Add for Profit" which allows a percentage for based on supply of the goods.
  • “Fix only" item accounts for prices for the labor and other costs associates with fixing the goods in a position.
• Provisional Sums and Prime Cost Amounts allowed in the Bill of Quantities will be adjusted in the "Final Account” to reflect the real or true costs.

Contingency Sum

• It is usual practice to include a “Contingency Sum" on the main summary of the Bill of Quantities.
• Sum can be an amount or percentage from the tender.
• Provides for any unforeseen costs.
• It provides any reserve fund to finance the cost from the unforeseen problems such as when rock is struck during excavation.
• The use of the contingency sum is solely at the discretion of the architect.