Controlling The Outcome Of Weathering Timber
We are often asked, “How can I keep my timber looking like it did when it was first installed?” The answer is not simple, but with thoughtful planning and regular maintenance, you can ensure your timber cladding ages beautifully over time. In particular, three crucial factors contribute to long-lasting, beautiful timber: Design, Installation, and Maintenance.
1. Design
The design phase is arguably the most critical stage when working with timber, as it sets the foundation for how the material will behave over time. Here are several important considerations to guide your design:
Weather Direction and Severity: Consider the primary weather patterns in your location. Which directions do the prevailing winds and rain come from? How severe are the seasonal changes? This will help determine how exposed or protected your timber cladding should be.
Protection from the Elements: Think about how to protect the timber from the most extreme weather conditions. For instance, designing overhangs or eaves can shield the timber from direct sun and heavy rain, which will reduce the potential for rapid weathering.
Material Selection: If timber will be exposed to harsher conditions, consider pairing it with more weather-resistant materials, such as stone, concrete, or metal, in fully exposed areas. This ensures that timber is featured in more sheltered or semi-protected zones, prolonging its lifespan and reducing the wear from weathering.
Understanding different rates of weathering: how you design a build will determine how the timber weathers. Walls facing different directions will weather at different rates, if there are obstructions or junctions which allow water and sun to hit at different angles this will all effect how the timber weathers over time and this must be considered in the design stage.
Obstructions and Design Gaps: Pay careful attention to areas around windows, doors, and other obstructions that could trap water. Gaps that are too narrow, or places where the timber meets other materials, can lead to water accumulation and could become breeding grounds for mould and unsightly discolouration.
Weathering Aesthetics: Fully exposed timber will weather differently depending on how water runoff interacts with the surface. Rain runoff might cause uneven fading or discoloration over time. If uniform weathering is a priority, it’s worth exploring techniques that help control how water interacts with the surface.
Waterflow Considerations: When designing your build, think about how water will run off the surface of the timber cladding. Proper design ensures that water doesn’t pool on or behind the timber, which can lead to moisture-related issues like swelling, rot, or mould. Consider how water will drain from the timber and whether it will be channelled away from vulnerable areas.
Design Details: Ensure there are adequate gutters, drainage channels, and flashing details to guide water away from the timber. Using bevelled or chamfered drip edges at the base of boards can also help prevent water from wicking back up on end grains.
2. Installation
The installation phase is where all your planning comes to fruition, and it’s vital to ensure the work is carried out correctly to minimise the need for future rectification. Installation guides and Australian standards should be followed at all times. Here are some additional tips for successful installation:
Proper Storage on site: Ensure that timber is stored correctly on site (undercover) and not picking up construction dust, moisture or any other construction contaminates prior to installation.
Proper Spacing: Ensure there is enough space between each board for natural expansion and contraction due to moisture content. This allows for airflow and reduces the chances of warping, swelling, or buckling.
Elevation from the Ground: Raise the timber off the ground to reduce contact with moisture, which can cause the wood to absorb water and accelerate the aging process. This also helps prevent rotting.
Ventilation: Proper ventilation cavities help keep moisture from accumulating on the back of the boards and prevents issues like mould and excessive movement.
Finishing: Boards should be finished with the desired application pre installation to ensure both the back and front of boards are uniform and protected from exposure to moisture and UV.
Flashing and Sealant: Use correct flashing which allows water to drain away from timber cladding especially around openings like windows and doors, and ensure sealant is applied where needed to prevent water from seeping into joints or behind cladding. If water can pool you will get water staining on ends of boards which can lead to degradation and mould.
3. Maintenance
While good design and installation can significantly improve the performance of timber cladding, regular maintenance just like any other building material is key to keeping it looking great for years.
Regular Cleaning: Ensure regular cleaning to remove dirt, debris, and organic matter (like leaves or moss) that can hold moisture against the timber. Use oxalic acid and avoid pressure washing where possible, as this can damage the wood fibres.
Timber Protection: Periodically reapply protective finishes, such as oils or stains, to maintain a protective layer over the timber. This helps guard against UV rays, moisture, and pollutants that accelerate weathering.
Addressing Wear and Tear: If parts of the timber begin to show signs of wear or discoloration, take corrective action early to prevent further damage. Sanding, re-sealing, or applying wood treatment oils can refresh the timber and help it maintain its appearance.
UV Protection: The sun’s UV rays can cause the wood to fade and crack over time. Apply a high-quality UV-resistant finish to slow down the weathering process and maintain the timber’s original colour, if desired. Reapplication might be necessary every 1-2 years, depending on exposure levels.
Moisture Control: Apply water-repellent finishes or treatments to reduce moisture absorption. This will help prevent swelling, cracking, and rot.
Periodic Inspections: Regularly inspect your timber for any signs of damage, such as cracking, splitting, or discoloration. Also look at other aspects such as gutters overflowing or water trap issues. Timely repair and treatment can extend the timber’s lifespan and reduce the need for costly replacements.
For a more comprehensive maintenance instruction check out our: Timber maintenance blog
By incorporating these key principles into the design, installation, and maintenance phases of your project, you can ensure that your hardwood timber cladding performs well and remains aesthetically pleasing throughout its life. With the right planning and ongoing care, your timber will maintain its beauty for many years to come, evolving gracefully with the passage of time.
