- Where not covered in this specification, formwork shall generally comply with the requirements of NZS 3109.
- Wherever necessary, formwork shall be used to support and confine the concrete and shape it to the required dimensions. Joints and linings shall be sufficiently tight to prevent loss of water from the concrete.
- All timber for formwork shall be of an approved quality and type. For kerbs and channels formwork shall be ex 40mm material provided that 15mm timber or other suitable material may be used on short radius curves.
- Formwork shall be of a sufficient depth to fully support all vertical faces and ensure that the specified concrete dimension is achieved within the allowable width & depth tolerances. Where it supports exposed surfaces, formwork shall be long lengths dressed smooth on one face and both edges.
- Timber strips for chamfers shall be machined all round to be true to shape and form and they shall be kept in good order. Alternatively the chamfer or bullnose may be formed with a specific floating tool or dressed fillets.
- Steel forms shall be of approved design and shall be maintained in good condition. The joints between lengths shall be secured accurately during concreting to maintain a good line in the finished work.
- Forms shall be designed to be easily removable without damaging the green concrete and shall be kept thoroughly clean and oil or wax dressed to prevent adhesion of concrete or rust staining. Forms for curved kerbs shall be brought to a true curve by springing the timber evenly.
- The shape, strength, rigidity, mortar tightness and surface smoothness of re-used forms shall be maintained at all times. Warped or bulged timber is not permitted. Timber which has been used shall have the surfaces which are to be in contact with the concrete thoroughly cleaned and treated before being used again.
Definitions in this section