Refer to ~ for ~.

Refer to the general section 1232 INTERPRETATION & DEFINITIONS for abbreviations and definitions used throughout the specification.

The following abbreviations apply specifically to this section:

Refer to the general section 1233 REFERENCED DOCUMENTS.  The following documents are specifically referred to in this section:

Manufacturer and supplier documents relating to this part of the work:
Firth + Environmental Product Declaration
Declare label
EC3 Embodied Carbon Calculator certificate

Manufacturer/supplier contact details

Refer to 1270 CONSTRUCTION for requirements relating to qualifications.

Where a product or material supplier is named in SELECTIONS, the product/material must be provided by the named supplier.  Where more than one named supplier, any one of the named suppliers will be acceptable.

Substitutions are not permitted to any of the specified systems, components and associated products listed in this section.

Carry out sampling and concrete acceptance tests during construction to NZS 3109.9. Concrete acceptance tests during construction.  Conduct 7 day strength tests.  After a 7 day test result of less than 60% of the specified strength, stop concrete placement until it is shown that the suspect concrete compiles with the specification.

Carry out slump tests, yield tests and air content tests to NZS 3112.1, sections 4, 5 and 9, and evaluate to NZS 3104 Control tests and their evaluation.  Make available all test records to the contract administrator on request.

Steel reinforcing and steel prestressing materials for concrete to AS/NZS 4671 or AS/NZS 4672.1, respectively.  Steel to be manufactured in New Zealand, or by an overseas manufacturer holding a current valid NZ S Mark or ACRS certificate for that type of steel.  Confirm compliance and provide evidence if requested.
Steel that fails to meet these requirements is not to be used (or ordered) without the contract administrators written approval, further proof and/or testing may be required.

Carry out the whole of this work to the requirements of NZS 3109.

Quality assurance procedures to include all aspects of concrete construction including;

• Formwork quality
• Reinforcing steel placing
• Cast in items
• Concrete quality
• Concrete finishes
• Construction tolerances

Advise the name of the suitably qualified and experienced representative who is responsible for quality control of the concrete work.  The representative is to sign a written quality control checklist for each on-site concrete pour.  Provide a copy to the construction reviewer in sufficient time for a pre-pour inspection on request.

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The waterproofing for openings system is covered in the following section:
~
To be done by others.

The weathertightness system is covered in the following section:
~

To be done by others.

Standard and / or specific grades of ready-mixed concrete (covered by Firth EPD) with a combination of:

• Cement to NZS 3122.
• Coarse and fine aggregate to NZS 3121 .
• Supplementary cementitious materials to comply with respective standards.
• Secondary materials to comply with respective standards.
• Water to NZS 3121.
• Admixtures to NZS 3113.

Refer to SELECTIONS for strength grades.

As agreed before mixing or placing.  Submit details in writing to the contract administrator.

Concrete 10 MPa with minimum water for workability, all materials and batching to NZS 3104.

Concrete having a minimum strength of 10 MPa at 28 days.

To AS/NZS 4671.  Round bars are shown by symbol "R" and deformed bars by symbol "D", followed by the diameter in millimetres.

To AS/NZS 4671.  Round bars shown by symbol "HR" and deformed bars by symbol "HD" followed by diameter in millimetres.

Hard drawn steel wire spot welded with correct gauge to AS/NZS 4671 Class E, smooth or deformed and to the spacings and dimensions either specified or shown on the drawings.

For slabs on ground mesh to be welded reinforcing mesh to AS/NZS 4671, Class E, minimum to NZBC B1/AS1 - Grade 500E, 2.27kg/m2 (1.14kg/m2 in each direction).

Mild drawn steel wire not less than 1.2mm diameter.

Precast concrete or purpose made moulded PVC to approval.  Where concrete spacer blocks are used in exposed concrete work use blocks similar to surrounding concrete.

Dressing or merchantable grade radiata pine to NZS 3631 for shutter face, to obtain the concrete finish specified.

An approved proprietary steel formwork and shutter system.

To AS/NZS 2269.0 for shutter face with plywood grade as necessary to obtain the concrete finish specified.

No. 2 framing radiata pine or as required to construct the required formwork.

A release agent that will not stain or adhere to the concrete, contaminate reinforcing steel or construction joints, or have a detrimental effect on any finished surface or applied finishes.

0.25mm minimum polyethylene to NZS 3604, 7.5.4, Damp-proof membrane.

Proprietary polystyrene foam board to AS 1366.3.  Refer to SELECTIONS.

Unreinforced wet area membrane to AS/NZS 4858 for waterproofing around openings for windows, doors, meters and other services openings, at or above floor level, also parapets and ends of masonry walls abutting other claddings to CCANZ CP 01. Refer to SELECTIONS.
Do not use bituminous coatings.

Refer to 1270 CONSTRUCTION for requirements relating to delivery, storage and handling of products.

Handle and store reinforcing steel and accessories without damage or contamination.  Store on timber fillets on hard ground in a secure area clear of any building operation.  Lay steel fabric flat.

Ensure reinforcement is clean and remains clean so that at the time of placing concrete it is free of all loose mill scale, loose rust and any other contamination that may reduce bonding capacity.

Refer to 1250 TEMPORARY WORKS & SERVICES for protection requirements.
Refer to 1270 CONSTRUCTION for requirements relating to defective or damaged work, removal of protection and cleaning.

Refer to the general section 1270 CONSTRUCTION for general requirements.

Design and construct formwork and falsework in accordance with sound engineering principles to withstand the worst combination of:

• dead loads of formwork, reinforcement, concrete and precast elements such as floor planks
• construction loads including dynamic effects of placing, compacting and construction traffic
• wind and snow loads

Provide all formwork necessary to support and confine the concrete and shape it to the required dimensions.  Fabricate in a manner permitting its easy removal without damage to the concrete.

Provide a 20mm x 20mm chamfer to all corners unless detailed otherwise.  Protect corners from damage during and after stripping.
Keep absorbent formwork wet before concrete is placed.  Clean formwork by waterblasting.

Carry strutting down to a construction sufficiently strong and stable to afford the required support without permissible stress or deflections being exceeded.  Prop through to other floors if the construction load on a particular suspended floor exceeds the design load.

Unless stated otherwise on the drawings permissible deviations from established lines, grades, dimensions and cambers to remain within the tolerances laid down in NZS 3109:  table 5.1, Tolerances for precast components and table 5.2, Tolerances for in situ construction.

Unless stated otherwise on the drawings, permissible abrupt, offset and gradual deviations for the specified surface finish to remain within the tolerances laid down in NZS 3114: table 3, Tolerances for abrupt deviations or offsets and gradual deviations.

Formwork linings and surface finishes as nominated for both fair face and concealed or exposed surfaces.  Unless detailed, obtain written confirmation of the type and pattern of all joints.

Construct joints to prevent loss of grout between joints in form linings, as well as between forms and completed work.  Column forms to have full height linings so that no horizontal joints occur on exposed faces.

Cambers shown on the drawings or specified, relate to the concrete immediately before formwork is struck.  Unless otherwise shown on drawings, construct forms to achieve the following:

• maximum deflection of face materials between strutting: 1/240th of span, but not exceeding 6mm.
• maximum deflection of beams: 1/900th of span
• maximum deflection of cantilevers supporting construction loads: 1/300th of cantilever length.

Ensure the safe removal of all or any part of the formwork.  Remove without shock, vibration or damage to the concrete and in such a manner as to take the imposed stresses gradually to NZS 3109.5.4.  Stripping times to NZS 3109 table 5.3.

Install to NZS 3604.7.5.6 Polyethylene (polythene) sheet damp proof membranes.  Bring granular hardfill to a suitable surface to receive the DPM using maximum 25mm sand blinding.
Lay the DPM on prepared basecourse with 150mm laps between sheets.  Seal laps and penetrations with 50mm wide pressure sensitive plastic tape.
Refer to drawings for perimeter details.

Install polystyrene insulation system to manufacturer's requirements.

Cut and bend bars using proper bending tools to avoid notching and to the requirements of NZS 3101.1, 8 and NZS 3109: 3.3 Hooks and bends.  Minimum radii of reinforcement bends to NZS 3101.1, 8 and NZS 3109: table 3.1, Minimum radii of reinforcement bends.  Do not rebend grade 500E bars.  Where rebending is necessary for grade 300E bars, use a purpose built tool, proper preparation and preheating.

Use a purpose built tool for on site bending and to deal with minor adjustments to steel reinforcement.

To NZS 3109, 3.9, Tolerances for reinforcement.

Secure reinforcement adequately with tying wire and place, support and secure against displacement when concreting.  Bend tying wire back well clear of the formwork.  Spacing as dimensioned, or if not shown, to the clear distance minimums in NZS 3109, 3.6, Spacing of reinforcement.

Length of laps where not dimensioned on the drawings in accordance with the SELECTIONS.  Provide laps only where indicated on the drawings.  Tie all lapping bars to each other.  Plain bars lapped splices must be hooked.
Wire mesh laps to NZS 3101.1, lap one mesh square plus 50mm minimum (do not count bar extension beyond the outermost wire).

For slabs on ground the welded reinforcing mesh to be lapped such that the outermost wires overlap by the greater of:

• the spacing of the cross wires plus 50mm
• 150mm or
• manufacturer's requirements

Do not count bar extensions beyond the outermost cross wire.

Minimum cover to all reinforcing bars, stirrups, ties and spirals, as shown on drawings.  Where cover is not shown on drawings provide minimum cover to NZS 3101.1, table 3.6, Minimum required cover for a specified intended life of 50 years.  Sub-soil cover to NZS 3101.1, to suit soil and groundwater conditions.  Fix chairs for top reinforcement in slabs at 1.0 metre centres or to ensure adequate support.  Cover tolerances to NZS 3109, 3.9, Tolerances for reinforcement.

For in-situ concrete, foundations and interior slabs on ground, to NZS 3604 or NZS 4229, the reinforcement and welded mesh cover to be:

Build in bolts and fixings for wall plates and bracing elements, holding down bolts, pipes, sleeves and fixings as required by all trades and as shown on the drawings, prior to pouring the concrete.

Location and form of conduits to be approved in writing by the Contract Administrator.  Minimum cover 40mm.  Do not encase aluminium items in concrete.  Do not paint steel embedded items more than 25mm into the concrete encasement.  Cut back form ties to specified cover and fill the cavities with mortar.

Form all pockets, chases and flashing grooves as required by all trades and as shown on the drawings.

Wrap all pipes embedded in concrete with tape to break the bond and to accommodate expansion.  Do not embed pipes for conveying liquids exceeding a temperature of 50°C in concrete.

Locate and construct as shown on the drawings or in accordance with
NZS 3109, 5.6, Type B.

If it is a project requirement, ensure that reinforcing is electrically equipotential bonded (or at least conductor cable attached) before the concrete is poured.  For bonded reinforcing ensure all reinforcing is interconnected with good contact at joints and tight conductive ties.

Do not place concrete until all excavations, boxing and reinforcing have been inspected and passed by the Building Consent Authority.

Do not place concrete in high winds or other unfavourable conditions.  Refer to NZS 3109: 7.2 Unfavourable conditions, for when concrete may not be placed.  Remove and make good concrete damaged by frost, dry and wet conditions.

Protect formwork, reinforcement, "build in" items and fresh concrete from damage, as the pour is placed, making good any damage if it occurs.

Transport concrete from agitator to final placement as quickly as possible using means that avoid segregation.

Set up and supervise pump operation, placing and compaction of the mix to NZS 3109, 7.4, Handling and placing and NZS 3109, 7.6, Compaction Advise the ready-mix supplier of the type of pump and the slump required, in addition to the concrete grade, strength and quantity.

Place concrete in layers not more than 500mm deep, compacted and vibrated.  Do not place fresh concrete against the preceding layer after more than 45 minutes, or such lesser time as required by the circumstances, to NZS 3109: clause 7.4, Handling and placing.

To NZS 3109: clause 7.6, Compaction.  Compact by vibration of the concrete to expel entrapped air and until settlement of the concrete is visibly evident over all areas of the surface.  Maintain vibration until settlement ceases and coarse aggregate at the surface is embedded.  Do not continue vibration beyond reaching this condition.

Use sufficient immersion vibrators, with one spare for emergency, to ensure that vibration is achieved throughout the entire volume of each layer of concrete, and until complete compaction is reached, to NZS 3109: clause 7.6, Compaction.

Generally for slabs on ground to NZS 3604 as modified by NZBC B1/AS1 and NZBC E2/AS3. Construct to NZS 3604, 4.5 Concrete and concrete masonry and NZS 3604, 7.5, Concrete slab-on-ground floors in timber buildings as modified by NZBC B1/AS1, 3.0 Timber.  Lay to true and straight surfaces, screeded, floated and steel (manual or power) trowelled finish.  Tolerance on flatness: maximum 3mm gradual deviation over a 3 metre straight-edge, to NZS 3114, 304, Surface tolerances.
Allow for free joints maximum 24m centres to NZBC B1/AS1, 3.1.13 NZS 3604 New clause.

Generally for slabs on ground to NZS 4229 as modified by NZBC B1/AS1 and NZBC E2/AS3. Construct to NZS 4229, 6, Footings and NZS 4229, 7, Foundation walls and concrete slab-on-ground as modified by NZBC B1/AS1, 2.0 Masonry.  Lay to true and straight surfaces, screeded, floated and steel (manual or power) trowelled finish.  Tolerance on flatness: maximum 3mm gradual deviation over a 3 metre straight-edge, to NZS 3114, 304, Surface tolerances.
Allow for free joints maximum 18m centres to NZS 4229, 7.8.5.3 Free joints.

Screed the concrete surface by straight edge or vibrating screed immediately after compaction and to tolerances in NZS 3109: table 5.2, Tolerances for in situ construction.

To NZS 3114, 105, Specification of finishes, for off the form finishes and to NZS 3114, Part 3, Floors, exterior pavements, and inverts, for slabs and pavements.  Refer SELECTIONS.

Cut slabs where indicated on the drawings as required to control shrinkage cracking.  Form by saw cutting the slab (blade width approximately 5 mm) to a quarter of the depth of the slab after it has hardened (saw cutting shall take place no later than 24 hours after initial set for average ambient temperatures above 20 ºC, and 48 hours for average ambient temperatures below 20 ºC).

Cut slabs where indicated on the drawings and as required to control shrinkage cracking.  Carry out cutting as soon as possible, without causing tear-out of aggregate and before shrinkage cracking has occurred, generally within 24 hours of pouring.

Clean out saw cuts.  Fill with cement grout where the floor will be covered with carpet or vinyl.

Cure all concrete of normal cement type and mixing proportions for a minimum of 7 days.  Keep time between placing of concrete and the start of curing to an absolute minimum.  Ensure curing is continuous.

Notify the curing method to be used for this work.  Select from the following methods;

• Ponding
• Sprinkling
• Wet coverings
• Plastic sheet
• Curing compound

Keep formwork left in place continuously moist by sprinkling with water over the curing period.  Continue sprinkling the exposed surface if the formwork is removed before the end of the curing period.

When covering with sheet materials, ensure that edges are well secured throughout the specified curing period, to prevent draughts passing over the surfaces of the concrete.

Do not use coverings employing water at times of freezing weather.

Protect plastic concrete from indentation and surface marking.

Protect surfaces of stripped concrete from damage especially at arrises.

Protect from rust marks and other surface disfigurements.

Reject concrete with structural defects.  Immediately after stripping formwork, identify all defects and obtain direction.  Do not carry out any repair work until directed and then only in accordance with the direction.  Repair defects by cutting out, making good and replacing, or otherwise as directed.

Make good surface defects immediately after forms are stripped.  Make good hollows or bony areas with 1:2 mortar or plaster, finished to the same tolerances as the parent concrete.  Fill any tie rod holes with 1:2 mortar.

Apply waterproofing to the exposed face of openings for windows, doors, meters etc, also if necessary the top of parapets/balustrades and ends of masonry walls abutting other claddings.  To CCANZ CP 01, waterproofing manufacturer's requirements and as detailed.
Provide temporary protection from direct sunlight.

Refer to 1270 CONSTRUCTION for completion requirements and if required commissioning requirements.

Where construction joints are not shown on the drawings, locate as follows:

Residential slabs on ground Free Joints modified by NZBC B1/AS1

Where reinforcement laps are not shown on the drawings, lap as follows:

Site concrete:

Mass concrete:

Surface finish class to NZS 3114: table 2, Classes of floor, exterior pavement and invert finishes.

Surface finish class to NZS 3114: table 2, Classes of floor, exterior pavement and invert finishes.

Surface finish class to NZS 3114: table 1, Classes of surface finish.

The weathertightness system is covered in the following section:
~

To be done by others.