Top 5 Questions When Selecting Timber Coatings

Timber decking makes a great addition to any outdoor area. While we love the natural look of timber, it’s important to keep it healthy with a water or oil-based timber coating. Without any protection, your timber deck or cladding won’t last long.

Whether you’re preparing to DIY or call in an expert to complete your outdoor job, you’re guaranteed to have plenty of questions about timber coatings. We’ve put together the top 5 questions to ensure you select the right finish for your timber. 

1. What’s the difference between water-based and oil-based timber coatings?

A water-based coating provides external protection around your timber, essentially adding a film (varnish) on the surface of the wood. The external protection helps to maintain the colour of the timber while also protecting against damaging UV rays. 

An oil-based timber coating works similar to a sponge. It penetrates deep into the pores of the wood, protecting it from the inside out. Oil-based products do not create a hard film on the surface, so they retain the timber’s rich, natural look.

2. How do I prepare my deck before applying a timber coating?

If you’re installing an outdoor deck, you’ll need to ensure your timber is prepared before you apply any protective coating. For a new deck, it must be clean and dry before applying any finish. If you’re adding a protective coating to an existing timber deck, there may be a little more work involved. 

When reapplying a water based timber coating, consider the condition of the existing coating. If it appears solid with no lifting or peeling,  you should clean the deck of any minor dirt and debris using a proprietary deck cleaner, allow it to dry thoroughly and then you’re ok to reapply the new coating. If the coating is in poor condition, you will need to remove any existing water-based finish i.e. lacquer or varnish. This can be done by sanding or stripping the timber – then clean well and re-apply with either water or oil based coating.

When reapplying to a deck with an existing oil based coating the process is much simpler – clean, allow to dry and reapply the oil based coating. 

Don’t leave it too long before applying a new coat. Some timber will begin to lighten or ‘silver off’ within a few months. If you want to double check you’ve prepared correctly, talk to the timber experts at Austim.

3. How long before I need to reapply the timber coating?

There are so many variables that can change the recommended time to reapply your timber coating. It’s best to follow the manufacturer’s guidelines but, as a general rule, you should re-coat every 1-2 years. Cladding can be re-coated every 2-3 years.

The variables that will change the time frame can include: 

• whether you choose water or oil-based coating 
• if your timber is exposed to the sun and rain
• amount of foot traffic on the timber deck

4. Can I use the same timber coatings on all timber?

Today, there are so many varieties of timber coatings on the market. Some coatings are clear with minimal or no UV protection whilst others include tints or colours which provide greater UV protection. If your preferred wood is prone to leaching (the process where tannins leach out of the wood when it gets wet), you may choose an oil that helps minimise leaching. Talk to your timber supplier about your wood and its properties before you choose a coating.

5. What happens if I don’t use any timber coating?

If you leave your timber uncoated, your timber will dry out which can cause the timber to split or warp. If the timber is exposed to the rain or will experience humid conditions, it can be prone to mould and decay. Adding a water or oil-based finish to your timber adds a layer of protection against mould or mildew and regulates the level of moisture retained and lost, which keeps the timber stable. 

Timber that isn’t coated and is exposed to UV will begin to turn grey – this is the first sign that your timber is unhealthy. However, if you want to achieve a grey look, you can do it while keeping your wood healthy using products like CUTEK® Exterior Timber Oil or Intergrain Universal Timber Oil. It requires a fine balance of letting the wood weather naturally while using the right oil to keep the inside of the wood healthy.

If you need advice choosing the right timber coating for your decking or cladding, talk to the timber experts at Austim.

Austim is Perth’s leading timber supplier and carries a wide range of timbers, (including many hard-to-find varieties) and stock leading timber coating brands. Contact Austim today.