How to protect and maintain exterior timber

Exterior timber goes through a lot. It must withstand every passing season – the balmiest of summer days and the wettest of winters. Since 1999, Dryden has honed their expertise to help protect and enhance timber, with their flagship product Dryden WoodOil. Newly launched, Dryden OilStain helps protect and is specifically formulated for most exterior timbers in New Zealand climates.

Timber is hygroscopic, meaning it is vulnerable to moisture ingress. In wet, humid conditions, the timber expands. As it dries out, it contracts. This forms a constant, circular cycle which causes the wood to swell, warp, and crack, leaving indelible marks. 

UV radiation emitted by the sun also poses a threat to timber stability. Lignin, an organic polymer in the wood that helps provide strength, is sensitive to UV rays. Over time, the UV rays degrade the lignin, weakening the timber.

This process, known as photodegradation, causes the timber to fade to a pale grey. While this is an intentional design choice for some, others choose wood for its warmer tones. Regardless, with high UV levels in New Zealand, protection is essential.

At first glance, a stain enhances the overall appearance of timber. However, its purpose is deeply rooted in the wood’s structural integrity. It is an essential component to ensure timber remains beautiful, but also durable and functional for years to come.

Traditional oil and water-based stains work by forming a protective film on the surface of the timber. 

Traditional oil stains have a pigment and resin-dense composition, which creates a visible sheen. This acts as a protective barrier against UV radiation and moisture. 

As the wood expands and contracts with changes in moisture and temperature, the stress can lead to warping or cracking. The more moisture and weathering, the more pronounced the issue becomes. 

Water-based stains are composed of water and acrylic or latex binders which form a thin layer on the wood. While water-based stains dry more quickly, it’s hard to get an even finish with less time. Further to this, the water component of these types of stains can cause the wood fibres to swell, resulting in grain raise. The surface becomes rough to touch and the appearance dulls. 

With limitations to the solutions on offer, Dryden OilStain offers a remedy to maintain exterior timber, time and time again.

Like Dryden WoodOil, Dryden OilStain nourishes the wood from within. As it does not form a film on the surface, it will not flake, blister or peel.

The additions to Dryden OilStain are plant-based oils, which act as penetrating agents. Mixed with resins or binders, the stain adheres to the surface. It also contains a fungicide to help resist mould growth. The impact is enhanced water resistance, reducing the risk of warping, cupping, and splitting. 

Over time, photodegradation causes exterior timber protected with Dryden OilStain to fade to silver. To change the colour and enhance the UV protection whilst retaining character and grain, use Dryden Colourtone+. This pigment additive can be combined with Dryden WoodOil, Dryden OilStain, and Dryden WoodMaster. 

Providing proper maintenance is upheld, this combination ensures reduced silvering and added protection. For enhanced protection without the colour, Dryden OilStain can be mixed with Dryden ColourTone+ in ‘Slate’. 

The type of wood used is an important consideration, as different species have distinct compositions and characteristics. Softwoods like pine are more porous, while hardwoods like oak or kwila are less absorbent. 

Dryden OilStain is ideal for a variety of exterior timber species, including softwoods like radiata pine, and macrocarpa. Hardwoods like purpleheart, garapa, and vitex are also compatible. Other timber products that are suitable include modified timbers, plywood and laminated timbers. 

It can be applied to most exterior timbers including decking, outdoor furniture, new and old timbers, and dressed and band sawn timbers.

Once you’ve ascertained its suitability and chosen your products, check the coverage rate to ensure you purchase the correct amount. This will vary depending on the type of timber. For instance, for high-density hardwood, the coverage rate is approximately 10–12m² per litre. 

The recommended applicator is a fine bristle speed brush, but you can use a wide bristle brush, spray, or a roller. After the first coat, allow the stain to dry for 30–60 minutes before wiping off any excess with a cloth. 

Apply a second coat 24 hours later. When applying a second coat or a maintenance re-coat, application rates will vary. The affecting factors include the timber’s exposure and the timeframe between coats. For more information on the process, download the Dryden OilStain data sheet.

The maintenance frequency will depend on factors including timber type and grain, building design and sun orientation, coating colour, and application. 

Regular inspections should be carried out to check for wear. Look out for patchiness, discolouration, or a loss of water repellency. Addressing maintenance needs promptly prevents further deterioration, ensuring the best possible protection for the timber.

With its nourishing, penetrating properties and non-film-forming finish, Dryden OilStain is a testament to Kiwi ingenuity. By combining Dryden OilStain with Dryden Colourtone+, the colour customisation options are vast and the protection enhanced. Protecting and maintaining your exterior timber improves its performance and lifespan, saves money, and helps maintain the sanctuary found at home.

Learn more about Dryden OilStain.