Precasting stairs for our clients allows them to speed up their construction time line on site. The stairs can either be individual steps and landings typically with steel stringers or full flights with landing included.
Formstress can provide you with individual steps that would typically be bolted to the steel stringers.
We would recommend that these steps not be less that 60mm thick (spanning 900mm) and landings not to be less than 100mm thick.
Fixing the steps to the stringers can be a problem with the thin nature of the steps. We would recommend cast in inserts each side.
Precast stair units typically come to site with lifting eyes cast in the top and bottom surfaces. If eyes are required in specific locations (edge lifting) please notify Formstress. Site personnel should ensure chains and strops are of the correct length and not more than 30 degrees of vertical.
BALCONY SLABS
To help with timing on multi-storey projects, Formstress supplies precast balconies to contractors and clients looking for savings in on-site construction time.
These decks can be 100 to 250mm deep with nibs, penetrations for drainage, cutouts, drip grooves and sloping finishes to your architects requirements. They can be finished ready for tiling or waterproofing or used as formwork where a topping slab is laid over top.
Typically precast decks will have bars protruding as cantilever reinforcing. Check to ensure the overall width of each unit is less that 3.5m for trucking. Alternately, the cantilever steel can be cut short (300-400mm) and Reidbar couplers fitted on site.
Another option is to bend the bars up for cartage and re-bend the bars down on site. (This is not commonly preferred as the NZ codes require the steel to be reheated to bend back.)
Finishes: Decks are normally cast upright with a light broom finish to the top for tiling. Other surfaces would typically be ‘off-mould’.
When specifying your balconies include notes about:
- Edge details - filleted or square edged. (Preferred sizes are 10mm or 15mm fillets using Reid standard profiles otherwise non-standard timber is dressed down for us by our timber merchant.)
- Concrete mix. Coloured or special admixes.
- Reinforcing and covers required.
- Location and extent of any drip grooves.
- Cast in brackets for handrails, etc.
- Finishes to each surface - trowelled, light broomed, retarded, etc.
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