Fencing
Scope
This section covers the specification and detailing of fences, including;
- Glass
- Timber
- Steel
- Masonry
Australian Standards
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All components and installation shall comply with the relevant Australian Standards.
- AS 1926 Swimming pool safety
- AS 2423 Coated steel wire fencing products for terrestrial, aquatic and general use
- AS 1725 Chain-link fabric security fencing and gates
- ASTM: F 964 - Standard Specification for Rigid Poly (Vinyl Chloride) (PVC) Exterior Profiles Used for Fencing and Railing
Commencement
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Work shall commence as soon as practical after, but not before,
(a) the Builder has issued:
- a written order
- the relevant contract drawings, specifications and schedule of work
- written approval of any details provided by the Contractor
(b) all other site works adjacent to fences have been completed.
Installation
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Unless stated otherwise on the drawings, fence posts shall be firmly secured in the ground by 15 MPa concrete in holes not less than 200 mm in diameter x 600 mm deep. The bottom 200 mm of the hole may be filled with dry mixed concrete to permit the fence components to be secured before filling the holes with wet concrete to within 50 mm of the top.
Wet concrete splashes shall be removed from the fence using a wet rag.
Unless stated otherwise, tolerances shall be as follows:
- Line of fence relative to boundary: + 50 mm- 0 mm to neighbour’s property
- Posts vertical +,- 1 in 100
- Straightness of top of fence: +,- 30 mm
- Posts adequately supported: Must not move significantly under lateral loading
Fencing Materials
[+]Inspections and Tests
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The following inspections shall be performed.
| Item or Product | Inspection Required | Accept Criteria | Hold / Witness
|
| Drawings & Specifications | Inspect controlled documents | Controlled copy of latest issue on site | Hold
|
| Post length | Measure post length | Must be long enough for panel + footing + step | Hold
|
| Panel length | Measure length | Include allowance for post width | Hold
|
| Line of fence relative to boundary | Tape and string line | + 50 mm- 0 mm to neighbours | Hold
|
| Posts vertical | Tape and spirit level | +,- 1 in 100 | Witness
|
| Straightness of top of fence | String line or by eye | +,- 30 mm | Witness
|
| Posts adequately supported | Visual Apply force to each post Concrete in place | Must not move | Witness
|
| Gates | Open and close gate several times | Smooth operation clear of ground | Witness
|
| Cleaning of fence and site | Visual | No concrete splashes | Witness |
Notes
All tolerances shall be as shown, except where overridden by AS 1926.1, AS 1926.2 or AS 1725.
Potential Problems & Solutions
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Grade and Straightness
The top of any fence should be straight in plan and at a uniform grade. The Builder may find it expedient to erect string lines for the Fencing Contractor, clearly designating the position and grade of the top of the fence.
Boundary
It is essential that the exact position of the boundary be established before setting out the fence.
Insufficient Support for Posts
In order for fences to remain vertical over an extended period, they must be set in the specified depth of concrete within the ground. Reliance on rammed earth around the post is not adequate.
Untreated Timber
All timber for external use should be treated to ensure that it is not subject to rot or termite attack.
Number of Posts
Allow for posts at each end of the fence, except where a corner is to be built in.
Post Length
For fences consisting of discreet panels (eg welded wire panels or steel sheet panels) that are required to step up or down a sloping site, the posts must be long enough to cater for the height of the panel plus the depth to be set into the footing plus the height of the step. Since the last value varies depending on the slope of the land, the length of the posts may also vary.
Fence Length
When calculating the length of a fence consisting of discreet panels fixed either side of the posts, include the sum of post widths when determining the total length.