{{ propApi.closeIcon }}
Our industry
Our industry $vuetify.icons.faArrowRight
Economic research and forecasting Economics Housing outlook Tailored market research Economic reports and data Inspiring Australia's building professionals HOUSING The only place to get your industry news Media releases Member alerts Submissions See all
Business support
Business support $vuetify.icons.faArrowRight
Become an apprentice host Hire an apprentice Why host a HIA apprentice? Apprentice partner program Builder and manufacturer program Industry insurance Construction legal expenses insurance Construction works insurance Home warranty insurance Tradies and tool insurance Planning and safety services Building and planning services How can HIA Safety help you? Independent site inspections Solutions for your business Contracts Online HIA Tradepass HIA SafeScan HR Docs Trusted legal support Legal advice and guidance Professional services Industrial relations
Resources & advice
Resources & advice $vuetify.icons.faArrowRight
Building it right Building codes Australian standards Getting it right on site See all Building materials and products Concrete, bricks and walls Getting products approved Use the right products for the job See all Managing your business Dealing with contracts Handling disputes Managing your employees See all Managing your safety Falls from heights Safety rules Working with silica See all Building your business Growing your business Maintaining your business See all Other subjects COVID-19 Getting approval to build Sustainable homes
Careers & learning
Careers & learning $vuetify.icons.faArrowRight
A rewarding career Become an apprentice Apprenticeships on offer Hear what our apprentices say Advice for parents and guardians Study with us Find a course Get your builder's licence Learn with HIA
HIA community
HIA community $vuetify.icons.faArrowRight
Join HIA Sign me up How do I become a member? What's in it for me? Get involved Become an award judge Join a committee Partner with us Get to know us Our members Our people Our partners Mates rates What we do Mental health program Charitable Foundation GreenSmart
Awards & events
Awards & events $vuetify.icons.faArrowRight
Awards Australian Housing Awards Awards program National Conference Industry networking Events Building and Renovation Home Show HOMEFEST
HIA products
HIA products $vuetify.icons.faArrowRight
Shop @ HIA Digital Australian Standards Contracts Online Shipping and delivery Purchasing terms & conditions Products Building codes and standards Hard copy contracts Guides and manuals Safety and signage See all
About Contact Newsroom
$vuetify.icons.faMapMarker Set my location Use the field below to update your location
Change location
{{propApi.text}} {{region}} Change location
{{propApi.successMessage}} {{region}} Change location

$vuetify.icons.faPhone1300 650 620

Leaving frames exposed to the weather

Due to a range of current factors being experienced with material and supply challenges and recent floods a number of projects are experiencing construction delays and some timber frames are being left exposed to the weather for extended periods. This resource provides a guide on assessing and inspecting frames for damage.

In the event that you may need to pause the construction of a house for an extended period of time, due to circumstances beyond your control, you may have questions regarding temporary bracing of structure to ensure it remains unaffected.

Another question may be in relation to exposure of frames and other materials such as structural flooring that may be open to the external environment and how long is permissible before it effects the structural integrity of the building.

This resource provides guidance on these matters which has been sourced from relevant industry sectors and product manufacturers.  

Assessing the effects of moisture to timber framing

Ideally, covering the frame for the duration of any extended period of time left exposed or reaching for example partial lock up to ensure the weatherproofing of the structure would be best case to reduce the impact of moisture, however this is not always possible or feasible.

The last thing also you want to be doing is having to constantly be coming back to check and adjust tarps.

When does timber framed construction need to be assessed for moisture impacts when left exposed for extended periods of time or after extreme weather events? There is no simple solution for this. Each individual site would need to be assessed for the potential degradation of timber components and any rectification would then need to be considered.

Items that can affect a timber structure, but are not limited to:

  • Time of exposure
  • The protection of the structure
  • Amount of rain days
  • Time allowed for timber to dry (sun exposure)
  • Climate temperature.

When a partly built structure is exposed to the weather the level of degradation will depend on the effects listed above. Some timber may need to be replaced after a few months of exposure where other parts may be sufficient for use after 12 months of exposure.

Where timber has 20% or more of moisture content for prolonged periods of time, fungal degradation or decay may be present, especially in untreated timber. Fungal degradation should not be confused with mould, this would only be on the surface and would not affect the underlying timber.

Lightweight metal wall and roof frames

Metal wall and roof frames generally have an aluminium/zinc/magnesium alloy coating, this is similar to a metal roof that is designed for outdoor exposure where there would be little impact if frames are exposed for a few months.

If the structure was close to breaking surf, washing of the frame after a period of weather exposure before adding cladding and internal linings is recommended to remove any salt deposits.

Bracing sheets

The two most common types of sheet bracing used are structural plywood and orientated strand board. An important part of the sheet bracing which requires it to be fit for purpose are the areas were fixings are placed and at the sheet edges.

If these are to delaminate it may affect the structural adequacy and the sheer capacity of the fasteners and require partial or replacement of the sheets in more extreme circumstances.

Particleboard flooring

As soon as particleboard flooring has been fixed it should be protected from the weather. If this is not possible it is recommended that the flooring not be left uncovered for more than 3 months.

However, if the 3 months is exceeded the flooring manufacturer should be called upon for an opinion on if the boards are still satisfactory.

Exposed metal connections

Metal components used in structural timber applications shall be corrosive protected suitable for the particular conditions of use. The minimum protection as per AS 1684-2010 describes a protection of Z 275 galvanised. In the short to medium term (6 months) there would be minimal concern of the connections becoming corroded.

When timber is repeatedly wet and dried this can lead to the nailplates ‘withdrawing’ from the timber due to the timber contracting and expanding in the timber. It could be possible for the plates to completely remove from the timber. If a gap of 2mm> occurs the integrity of the structure would be affected.

Straps used in the structure may become loose due to the expansion and contraction of the timbers from continuous wetting and drying. These all would need to be checked on returning to site.

Temporary bracing

When leaving a site for extended periods of time there needs to be adequate temporary bracing applied to the structure. AS 1684-2010 describes temporary bracing shall be equivalent to at least 60% of the permanent bracing required.

Also temporary bracing may form part of the installed permanent bracing. When returning to site the temporary bracing may have moved causing walls and roof structures to no longer be correctly aligned or level. 

Steel beams, columns and lintels 

It is important that if the frame is to be exposed to the elements for some time that all structural steel is protected against corrosion. This can be achieved by ensuring the steel is provided with suitable coatings. These are specified in either the NCC or in accordance with relevant Australian Standards AS/NZS 4791, AS/NZS 4534, AS 1397 and AS 1214.

All metal used in structural timber connections shall be provided with corrosion protection appropriate for the particular conditions of use and taking into consideration weather exposure, timber treatment, moisture and presence of salt.

Before recommencing work

Where the frame has been sitting for some time and exposed to the elements either partially or fully it is recommended that the structure be inspected by a suitability qualified person before re-commencing work.

Further information

Timber Queensland has developed an excellent information sheet - 'Guide to Assessment and Repair of Flood Damaged Timber and Timber Framed Houses' which was revised in February 2022.

The guide covers the effects of flood damage on timber frames and components and structural damage to buildings among other things.

Download guide


To find out more, contact HIA’s Building Services team.

Email us

Share with your network:

More articles on:

{{ tag.label }} {{ tag.label }} $vuetify.icons.faTimes
Find guides, how-tos, resources and more

Building materials and products topics


Can’t find what you need, check out other resources that might be closer to the mark.

Carports & Pergolas - Design & Construction Manual

This construction manual is suitable for any design and construction work with timber carports and pergolas. It contains clear and concise information...

Hancock's Roof Cuts & Rafter Lengths

Hancock’s Roof Lengths and Rafter Lengths is well known throughout the building industry as the Little Red Roofing Book. No self-respecting roofer sho...

Pocket Span Table Book

The Pocket Span Table Book comes in an easy-to-carry, pocket-sized (A5), durable book in a spiral-bound format. It includes span tables for commonly u...

Timber Decks Design and Construction Manual

The Timber Decks Design and Construction Manual is an illustrated guide to the design and construction of low-maintenance timber decks for domestic ap...