Ultimate Guide To Kwila Deck Maintenance in New Zealand

Kwila – a beautiful, highly durable, dense hardwood of rich reddish-brown tones that’s naturally resistant to borers and decay. Because of these qualities, Kwila is widely used in New Zealand for decking and sometimes for other outdoor furniture and pergolas.
This premium timber has a longer lifespan than other decking timbers like pine, but that doesn’t mean it’s completely immune to the elements. Your Kwila deck needs regular maintenance to uphold its structural integrity and stunning aesthetic.
The good news is that Kwila deck maintenance is relatively straightforward and easy to carry out with Dryden! Here’s how to use Kwila decking oil or stain to maintain your deck:

Why Kwila Needs Maintenance
A Timeline of Kwila Maintenance Around the Home
How To Carry Out Maintenance For Your Kwila Decking Using Dryden Products

How to clean your Kwila decking
- For standard cleaning
- To remove stains and cosmetic marks on your Kwila decking
How to coat your Kwila decking
How to stain your Kwila decking
To restore Kwila decking before recoating

Diagnosing if maintenance or restoration is needed – What damage to Kwila decking looks like

Is it better to use oil or a traditional stain on Kwila?

Final thoughts on Kwila decking maintenance

Why Kwila Needs Maintenance

Kwila, or ‘Merbau’ as it’s called overseas, is a high-density hardwood that’s durable and resistant to borers. But, without regular care and maintenance, your Kwila deck will eventually:

Fade away – NZ’s harsh UV rays can bleach your decking, resulting in a dull grey or silver colouring.
Become discoloured – The humid climate of New Zealand encourages mould and mildew growth, which can discolour your Kwila deck.
Suffer from warping, cupping, and splitting.

Kwila is a premium timber that’s placed more on the pricier side, so you don’t want to let it deteriorate quickly. We recommend having a regular maintenance schedule for your Kwila deck because – if it’s properly cared for – the lifespan of your deck can be greatly expanded.

A Timeline of Kwila Maintenance Around the Home

New Kwila decking: Once installed, apply a high-quality wood oil like Dryden OilStain, which is a clear, water-repellant, deeply penetrating oil that helps protect the timber from the inside out.

If you want to add colour to your Kwila decking, add Dryden Colourtone+, which, in addition to adding beautiful colour to the timber, provides enhanced UV protection.

Every six months: We highly recommend giving your Kwila decking a wash at this stage. Clean off dirt and grime using a garden hose or soft brush (such as a car washing brush). A mild detergent solution can be used to remove stubborn contaminants.

Ongoing maintenance: Reapply the coating when the Kwila deck has lost its water resistance and water is soaking into the timber.

Conduct routine maintenance inspections every six months to ensure the timber is still protected from water or as frequently as necessary to retain the preferred appearance.

How To Carry Out Maintenance For Your Kwila Decking Using Dryden Products

How To Clean Your Kwila Decking

For Standard Cleaning

Wash every six months: The standard way to clean your Kwila decking is with a thorough wash, which we recommend doing every six months. You can use a garden hose or soft brush (such as a car washing brush). A mild detergent solution can be used to remove stubborn contaminants.

To Remove Stains And Cosmetic Marks On Your Kwila Decking Before Recoating

What to use: Dryden LiquidTimberClean

How does it work: Dryden LiquidTimberClean helps lighten or remove marks and brightens dull Kwila.

How to use:

Mix Dryden LiquidTimberClean 50/50 with water
Apply directly to the entire deck
Keep wet and active until marks are acceptable or gone
Blend the total area with the 50/50 mix once marks are gone or timber is brightened
Rinse with clean water until soapiness is gone, especially in grooves and joints
Re-oil timbers for protection after drying
The process applies to general or targeted cleaning

How To Coat Your Kwila Decking

What to use: Dryden OilStain

How does it maintain your Kwila decking? Dryden OilStain is one of the best Kwila decking oils you’ll find in New Zealand. It is a water-resistant, deeply penetrating oil that nourishes your Kwila from within, helping to remove excessive warping, cupping, and splitting of timber and extending its lifespan.

How to use it:

Use a wide bristle brush or a speed pad: just avoid the lambswool types! An airless spray system can also be used to apply the oil to your decking.
Regularly stir the wood oil throughout the application process to maintain a consistent colour.
Don’t thin or dilute: Dryden OilStain should not be thinned or altered in any way – you simply apply it to the wood surface and wipe off any excess solution. After the initial 30-60 minute waiting period, allow the deck to dry before applying another coat – it’s as easy as that!

How To Stain Your Kwila Decking

What to use: Dryden Colourtone+ added to Dryden OilStain

How does it maintain your Kwila decking? Dryden Colourtone+ provides UV protection and helps prevent the timber from silvering when maintained correctly.
How to use it: Choose from over 37 colours and add the selected stain to Dryden OilStain. Then, carry out the same application method.

To Restore Kwila Decking Before Recoating

What to use: Dryden LiquidTimberClean

How does it work: Dryden LiquidTimberClean helps remove silvering, mould, dirt and grime, and mild watermarks from Kwila decking. You can apply it to restore your decking before recoating with Dryden OilStain.

How to use:

Mix LiquidTimberClean with equal parts of clean water in a container.
Apply the mixture directly to the surface to be cleaned.
Saturate the surface to be cleaned, starting from the bottom and going to the top.
Leave the mixture on for 15 minutes, making sure to keep the surface wet with a spray mist.
After saturating, rinse the mixture off using high-pressure water.
Use long sweeping motions in the direction of timber, feathering on and off at the end of each sweep, starting at the top of the area to be cleaned.

Diagnosing If Maintenance Or Restoration Is Needed – What Damage To Kwila Decking Looks Like

Silvering: This happens when coloured timber extractives are washed out (leaching), and the Kwila structures get damaged by sunlight (photodegradation).

Dryden OilStain helps Kwila maintain a grey look while still offering protection against moisture. So, it may not mean that your decking needs re-oiling or coating in this specific case. Silvering only indicates the need for coating and colour when you want to maintain a natural or stained look.

Is It Better To Use Oil Or Traditional Stain On Kwila?

If you want a clear/transparent oil for a natural silvered look, go for Dryden OilStain. If you want a different or more colour, add Dryden Colourtone+ to Dryden OilStain. Doing so will also enhance the UV protection of your deck.

A big question we get asked a lot is, “Is it better to oil or stain a deck?” This is a tough question to answer. Instead, let’s reframe it to be more specific: Should I use a Kwila decking oil or a traditional stain?

In our terms, staining means adding colour. So, when you use a combo of Dryden OilStain + Colourtone+, you’re essentially staining the timber. This is why it comes down to your preference for the look and finish you want on your Kwila decking.

Final Thoughts On Kwila Decking Maintenance

Here are a few key points to remember about Kwila deck maintenance:

Kwila is a beautiful, dense hardwood with natural resistance to borers and decay, making it ideal for decking and other outdoor structures.
To keep your Kwila deck looking beautiful, regular maintenance is important. This includes:
- Regular washing every 6 months and preparing with LiquidTimberClean
- Applying Dryden OilStain with or without Dryden Colourtone+ as needed
- Inspecting the deck for signs of damage every two to three years
Silvering, mould and mildew growth, fading from UV exposure, warping, cupping and splitting are signs that your Kwila may need maintenance or restoration.
Whether you use a traditional stain or oil on your Kwila depends on the look and finish you want – get a clear finish by just using Dryden Oil Stain or use OilStain and Dryden Colourtone+ for a stained finish.

Got more questions we haven’t answered here? Visit our FAQ page to see some of the biggest questions about using OilStain for decking maintenance. If you’re ready to get started, browse through all our timber care products here and find them at your local Dryden reseller.

Timber Maintenance Guides

Kwila Deck Maintenance