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Chapter 5

SPECIFICATIONS

Introduction

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Guidelines for a Well Prepared Specification

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Standards

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References

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Introduction

It is absolutely vital to create a comprehensive specification for any building project; one cannot use general notes and provisions for accurate costing purposes. As the word suggests, a specification contains specific information. For example, a door is not simply a door – it has a frame and furniture (hinges, handles, locksets) and can be made from a number of different materials.

To estimate the cost of a project without a specification is impossible and to enter into a contract without one is very short sighted. Too many building contracts are entered into with vague information, resulting in a myriad of problems; the most common being significant cost overruns. The specification should form an integral part of the building contract. It is also important to note that there is no such thing as a standard specification as no two structures are alike or use the same materials. In some countries construction specifications for building work are written using specification systems purposely designed describing activities, products and other requirements into a standard order; with each activity or product designated a special code. For example in the United States and Canada the MasterFormat™ system is used and in the UK the RIBA system is used.

Unfortunately there is no standard system used in South Africa with many professionals and organisations making do with in-house systems that suit their requirements. One company in South Africa that has taken construction specifications into a new era over the last decade has been Autospec. Autospec originally marketed their professional specification software system to architects only and have in the recent past broadened their market exposure to the general public and contractors with different software packages available to suit the user and building segment.

Another South African product that has facilitated with specifications to the residential building industry for over 21 years has been the Buildaid Building & Pricing Guide1. This Annual publication forms the basis of a building specification and follows a standard sequence for identifying and referring to the required construction information needed for a well prepared specification; with each section and sub-section providing important information on a number of products, trades and/or activities.

Guidelines for a Well Prepared Specification

The following categories act as a guide for a well prepared specification and where required, the sub-groups would need to be described in detail for a specification to be complete.

General requirements

  1. Scope of work
  2. Contract agreement forms
  3. Conditions of contract
  4. Certificates and other forms
  5. Variation procedures
  6. Valuation procedures
  7. Payment procedures
  8. Allowances (PC sums)
  9. Administrative requirements
  10. Plan approval and regulatory requirements
  11. Construction Progress Documentation
  12. Quality control
  13. The completion and handing over process
Preliminaries
  1. Site assessment
  2. Site layout
  3. Insurance details and procedures
  4. Access roads and parking
  5. Temporary barriers and enclosures (hoarding)
  6. Storage areas
  7. Temporary storage and offices
  8. Temporary service connections
  9. Water and electricity consumption
  10. Waste removal
  11. Location of major plant
  12. Material requirements, options and tests
  13. Material delivery requirements
  14. Demolition work
  15. Stormwater management
  16. Site security
Earthworks
  1. Soil conditions
  2. Geotechnical Investigation
  3. Site clearing & levelling
  4. Compaction
  5. Boundaries and datum peg
  6. Groundwater/subsoil drainage
  7. Building lines
  8. Foundation type(s)
  9. Excavation methods
  10. Setting out and orientation
  11. Soil poisoning
Concrete
  1. Schedules for concrete
    • Site mix or ready-mix concrete
    • Select strengths of concrete and/or aggregates
    • Cement
    • Mix proportions
    • Concrete admixtures
    • Concrete compaction
    • Concrete finishing
    • Concrete curing
    • Concrete tests
  2. Concrete reinforcing
  3.  Reinforcing steel
  4. Welded wire mesh reinforcing
  5. Structural concrete
  6. Architectural concrete
  7. Concrete surface beds
  8. Concrete floor or roof slabs
  9. Floor levels
  10. Concrete stairs
  11. Precast Concrete
  12. Precast structural concrete
  13. Precast architectural concrete
  14. Construction and movement joints
  15. First fix items for plumber and electrician
Damp-proof membranes and thermal insulation
  1. Damp proof membranes –
    • Masonry (horizontal)
    • Under Surface Bed (USB)
    • Vertical
  2. Thermal insulation –
    • Perimeter or Edge Insulation
    • Slab on Ground (SOG) Insulation
Masonry
  1. Schedules for mortar
    • Select aggregates and mortar strengths
    • Cement
    • Mix proportions
  2. Schedules for masonry (bricks or blocks)
    • Type (e.g. Clay stock brick)
    • Compressive strength
    • Water penetration
    • Bonds (e.g. stretcher)
    • Brick reinforcement
    • Pointing and Jointing
  3. Cavity walls
    • Thermal Insulation
  4. Lintels
    • End bearing
    • Support
  5. Roof anchoring
  6. Roof height (see fig 4.3)
  7. Window sills
  8. Brickwork movement
  9. Fireplaces and chimneys
  10. Arches
  11. Columns
  12. Freestanding walls
  13. Copings
  14. Corbelling
  15. Stone Masonry
  16. Scaffolding
Windows
  1. Window and door schedules
  2. Type and make of window (e.g. steel or wood)
  3. Sizes of windows (sizes vary between suppliers and the windows may be fitted later in the building process)
  4. Type of glass to be used in each window (this forms a glazing schedule)
  5. Position of each window in the structure
  6. External and internal window sills per window – positioning of the window in the wall
  7. Burglar proofing
  8. Special features to the structure around the window – Finish to the window (e.g. paint)
    Figure 5.1 – Examples of a window schedule
    Doors
    1. Type of door frame (e.g. steel or wood)
    2. Position of each frame in the structure, in the wall and position of hinges i.e. opening in or out
    3. Type of door (e.g. Solid wood or Masonite)
    4. Special features (e.g. install a door closure)
    5. Ironmongery details (e.g. lock and hinges)
    6. Finish of frame and door (e.g. paint) 
    Figure 5.2 – Examples of a door schedule

    Note:
    Window and door positions and heights (the height of a door is always measured from the floor level, which is conventionally 2125mm to lintel height. A window is measured down from lintel height, so if the window is 1200mm in height, then 1200mm will be measured down from 2125 which is the lintel height). See Figure 5.3.

    Figure 5.3 – How window and door heights are measured for a specification
    Waterproofing
    1. Schedules for waterproofing
      • Retaining walls
      • Basements or cellars
      • Balconies
      • Roof slabs
      • Abutments
    2. Bituminous waterproofing
    3. Sheet waterproofing
    4. Sprayed waterproofing
    Roofing
    1. Schedules for roofing
      • Roofing type (e.g. Timber or light steel trusses)
      • Concrete slabs (e.g. Hollow core slab)
      • Details of structural requirements
      • Roof covering (e.g. Double roman concrete tile)
      • Overhangs
      • Facia and eave details
    2. Rainwater disposal (e.g. gutters)
    3. Skylights
    4. Roof windows
    5. Vapour and dust barriers
    6. Thermal insulation (refer SANS 10400 part XA)
    7. Roof ventilation
    8. Roof vents
    9. Fire and smoke protection
    Plumbing
    1. Schedules for plumbing
      • Municipal connection
      • Drainage layout
      • Hot and cold water distribution
      • Water heaters and location (e.g. solar or electric)
    2. Each plumbing point must be marked on the drawing showing the exact position (e.g. bath)
    3. The finished height of certain fittings must also be indicated (e.g. vanity slab)
    4. External garden taps and other fittings (e.g. valves) must be considered
    5. Sanitaryware and Fittings
      • Clearly define fittings by supplier code and description
      • All items should be clearly marked on the specification as to where they will be fitted in the structure (and then first, second and final fix items must be described)
    6.  Fixtures and fittings in the kitchen (e.g. the zinc, dishwasher, washing machine, fridge).
    7. Other fittings like flashings and gutters

    Note: The coordination between the kitchen contractor and plumber is essential.

    Electrical
    1. Schedules for electrical
      • Electrical layout – Each point must be clearly marked on the drawings e.g. plugs, lights, light switches and to which lights, water heater point, telephone, TV, intercom, stove, etc.
      • Location of distribution board
      • Types of switches and socket outlets (plugs)
      • Two way switching
      • Dimmers
      • Occupancy sensors
    2. Emergency lighting
    3. External lighting
    4. Light fittings
      • Light fittings should be specified or at least a provisional amount should be allowed
    5. The length and type of cables from the boundary to pools and outbuildings must be specified
    6. Specify the required wire sizes and current ratings for different circuits
    7. Type of supply required – 240V (2 phase) or 380V (3 phase)
    8.  Appliance positions in kitchen (e.g. Oven and Hob or Stove or combination)
    9. HVAC requirements

    See Figure 5.4 for and example of an electrical layout

    Figure 5.4 – Example of an electrical layout
    Plastering
    1. External and internal plaster types
    2. Choice of aggregates
    3. Screeds and toppings
    4. Soffit finishes
    5. Two coat plaster details
    6. Special features e.g. door thresholds

    Note: A sample panel should always be used on site to ensure consistency and used as a reference for quality and texture.

    Ceilings
    1. Describe the type of ceiling by room
    2. Thermal insulation (refer SANS 10400 part XA)
    3. Finish to ceilings (e.g. Rhinolite, paint)
    4. Ceiling heights
    5. Bulkheads
    6. Type of cornices per room
    7. Position of trap doors
    Carpentry and Joinery
    1. Skirting’s and quadrants
    2. Windowsills
    3. Architraves
    4. Panelling
    5. Special features such as staircases
    Ironmongery
    1. Schedules for ironmongery
      • Hinges per door
      • Locks and door handles per door
      • Other fittings (e.g. door closures, kick plates, indicator bolts, door stops etc.)
    2. Towel rails and rings and position for fitting
    3. Type of curtain tracks
    4. Specify specialised fittings (e.g. rebate kits)
    Metalwork
    1. Metal framing
    2. Structural metal
    3. Metal Stairs
    4. Railings and balustrades
    5. Decorative metal
    6. Metal gratings
    Glazing
    1. Glazing schedule
      • Glass type and thickness – refer SANS 10400 Part N – for safety regulations
      • Solar control
      • Security considerations
    2. Mirrors
    3. Plastic glazing
    4. Glazing surface films
    Painting
    1. Schedules for painting
      • Type and colour of paint per room, and number of coats (walls and ceilings/soffits)
      • Preparation requirements
      • Include doors and frames, window frames and mouldings
    Tiling
    1. Schedules for tiling
      • Type of tile per room
      • Tiling layouts
      • Special features and patterns
      • Heights of wall tiling
      • Tile adhesive
    2. Soap dishes, paper roll holder and positions
    3. Colour of grouting
    4. Fittings (e.g. wall/edge trims)

    Note: When allowing an amount for tiling per m2 the quantity to be laid must be specified.

    Floor coverings
    1. Schedules for floor coverings
      • Flooring type per room (e.g. main bedroom – laminate)
      • Specify underfelt (where textiles are used)
      • Special features (e.g. patterns or inlays)
      • Screed finishes (e.g. Float or steel trowel)
      • Sound insulation
      • Thresholds
      • Fittings (e.g. transition strips, nosing’s, etc.)
    2. Under floor/carpet heating
    Specialised trades

    Note: Finished floor levels need to be specified to accommodate different flooring thicknesses.

    1. Alarms, security systems and intercoms
    2. Bars and pubs
    3. Freestanding fireplaces
    4. Garage doors
    5. HVAC Systems
    6. Kitchens and cupboards
      • A specialist kitchen contractor is always recommended to undertake this activity. This specialist will be able to design a kitchen and cupboards to the requirements of the employer. This process should be concluded before the superstructure is completed to avoid any late structural changes.
      • Choice of cooking appliances must be chosen to allow for plumbing, electrical and gas connections. Refer Table 5.1 for an example of a kitchen planning specification check list.
    7. Showers and shower doors
      • Safety must be considered and reference must be made to SANS 10400 part N
    8. Staircases and balustrades
      • Safety must be considered and reference must be made to SANS 10400 part D and part N
    9. Strong rooms and safe doors
    10. Wine cellar
    External works
    1. Awnings
    2. Boreholes
    3. Decking
    4. Fencing and precast walling
    5. Gates and metalwork
    6. Landscaping
    7. Paving
    8. Saunas
    9. Skylights (also covered in roofing)
    10. Solar heating
    11. Spa baths
    12. Swimming pools and water features
    13.  Tennis courts and squash courts

    Note: The above list describes the most common items and is non-exhaustive and is offered as a guide only and the publishers cannot be held responsible for any omissions.

    Table 5.1 – Kitchen Planning and Specification Check List

    Standards

    As can be seen from the extract below from SANS 10400 the choice of materials specified for a building project is very important and must be fit for the purpose intended. The fundamental properties of a material must be judged against the functional requirements of a given project and of course the functional requirements of the National Building regulations.

    Extract from the National Building Regulations (NBR) – SANS 10400 Part A
    A13 Building Materials and Tests

    (1) (a) Material used in the erection of a building shall be suitable for the purpose for which it is to be used.
    (b) All timber used in the erection of a building shall be treated against termite and wood borer attack and fungal decay in accordance with the requirements of SANS 10005 and shall bear the product certification mark of a body certified by the South African National Accreditation System.
    (c) The requirements of subregulation, (1)(a) shall be deemed to be satisfied if such material complies with and is incorporated into buildings in accordance with the requirements of SANS 10400.

    (2) The local authority may test or cause to be tested any material or component used or to be used in the erection of any building in order to determine whether such material or component complies with the requirements of these Regulations, and any officer of such local authority duly authorized for that purpose may, at any time after consultation with the person erecting such building, remove from the building site concerned so much of such material or component as is reasonably necessary to serve as a sample for the purpose of such test: Provided that the authorized officer may not exercise his powers in such a way that work of such erection is stopped when such material or component is being so removed and tested.

    (3) If any material or component tested in terms of subregulation (2) does not comply with these Regulations the local authority may serve a notice on such person, stating the respects in which such material or component does not comply and prohibiting such person from making further use of such material or component for the purpose for which it was or is to be used in the erection of such building.

    (4) Except in the case where in such notice the local authority permits the use of such material or component in the erection of such building for some different purpose permitted in terms of these Regulations, such person shall forthwith on receipt of such notice remove such material or component from such building or building site or from both, as the case may be.

    (5) If any material or component contemplated in subregulation (2) is tested and has failed to comply with these Regulations the local authority may recover the cost of such test from the owner of the building concerned.

    (6) Where the owner of any building desires to use for a particular purpose any material or component which is not permitted or prescribed by these Regulations to be used for that purpose, and he satisfies the local authority that such material or component is at least as suitable for that purpose as the material or component permitted or prescribed to be used by these Regulations, then the local authority shall permit the use of such material or component for the purpose concerned.

    References
    Alexander G D & Alexander G C. 2010. Buildaid Building and Pricing Guide 2010/11. Johannesburg: Buildaid Publishing.
    Alexander G D & Van As F. 2008: Civil Technology. Johannesburg: EWA Publishing.
    South African Bureau of Standards. 2011/12 – SANS 10400 Part’s A; D; & N. Pretoria. SABS Standards Division.
    Spence, W & Kultermann, E. 2011. Construction Materials, Methods & Techniques (International edition). Third edition. USA. Cengage learning.