LOOKING AFTER TIMBER or steel framing, particularly until the building is closed in, is essential to achieving a result for the client that is durable and serviceable. It encompasses:
planning the order of deliveries – ground-floor frames, first-floor frames, roof trusses or rafters in the right sequence
providing access for delivery vehicles
designating a clear level storage area for additional framing or a temporary holding area when frames and trusses cannot be lifted directly into their final location
protection of stored materials that need to be kept dry, such as manufactured floor joists
safe manual handling on site as frames and trusses are installed in their final location, particularly for first-floor frames and roof members
integration with the laying of the upper floors
managing weather and UV exposure where limits apply.
Plan deliveries to reduce handling
The ideal is for the frames and trusses to be delivered immediately before they are scheduled to be erected so they can be lifted into their final position and manual handling and storage time is minimised.
This involves:
truck access or at least being within safe reach of the truck’s hiab
ensuring frames and trusses are not racked during lifting
having temporary braces ready to install as the wall frames are erected
planning deliveries in the correct order to follow the installation of the ground-floor walls for a 2-storey building – first-floor framing, flooring, upper-floor walls, roof framing, roof underlay and cladding.
Tips for good timber framing storage
Provide correct storage for frames, trusses and packet or loose timber until they can be erected:
Fabricated items such as trusses, I-beams and prenailed frames should ideally be stored within a building or constructed shelter. Although material may be stored under covers, this should only be for a limited time, or the covers will need maintenance to ensure the timber stays dry.
Provide a dry, level, even base for storage. If outside, cover the ground with polythene immediately under the stack to avoid water condensing on the timber.
Support all stored timber clear of the underlying surface on evenly spaced dunnage.
Keep all kiln-dried framing covered. For packet timber, do not remove the protection until the timber is needed.
Do not store steel or timber frames or trusses over a newly poured slab or wet sheet floor.
If delivered as wet framing, fillet stacking will allow timber to dry before use.
Things to avoid
Other examples of poor frame and truss care include:
tipping it from the delivery truck and leaving it where it lands
not storing it clear of the ground on dunnage
providing uneven or insufficient dunnage under the material so that it is not on an even or level base
leaving kiln-dried timber uncovered and exposed to the rain or not effectively protecting the timber from wetting
using it as a storage platform for other materials, causing deformation
allowing timber to sweat under covers
leaving steel or timber trusses lying uncovered on uneven ground among the grass or in the dirt, which can lead to distortion
misaligned bearers or dunnage.
Handling on site
Where frames and trusses have to be manually handled on site:
carry trusses and frames upright (see Figure 1)
have sufficient labour to spread the load and minimise the flexing of the frames and trusses.
Exposure limits for steel and timber
While there are no specific weather exposure limits set for both timber and steel framing, it is prudent to take these actions:
Minimise exposure by enclosing the framing as soon as is practicable. Where H1.2 boron treated timber framing has been left in the weather for more than 3 months – timber stored uncovered on site or as erected frames – verification that the treatment level is still adequate to satisfy the requirements of NZS 3640:2003 Chemical preservation of round and sawn timber may be required.
Keep floors the framing is installed over free of ponding water – remove bottom plates at doorways to allow water to drain.
Consider specifying a proprietary packer system, installed in accordance with the specific system instructions, that supports bottom plates clear of the floor.
Health and safety
Erecting first-floor and upper-floor structures, upper-floor wall frames and trusses is classified as working at height – over 3 m. That brings into play requirements to ensure that the work can be carried out safely, such as:
edge protection – scaffold
fall protection or restraint
barriers at upper-floor levels.
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