A Simplified Guide To Restoring Kwila Decking From Its 4 Biggest Threats

A beautiful outdoor area is the pride and joy of a homeowner, especially when the deck is made out of Kwila, a premium hardwood timber renowned for its durability and rich colour. So, when your Kwila deck shows signs of wear and tear or succumbing to the elements, it can cause concern.

Not to worry. Thanks to Dryden, restoring your Kwila decking is simple and straightforward. Our deck restoration and maintenance products are designed to address the common issues timber decks, including Kwila, face in New Zealand.

5 Common Issues With Kwila And How To Restore Them

Discover how to restore Kwila from its four biggest threats using Dryden.

1. Cupping, warping, splitting and wood fuzzies

How to identify:

  • Look out for these visible deformations:
  • Cupping – when the edges of timber boards are higher than the centre and form a concave shape
  • Warping – twisting of the kwila boards
  • Clear surface splits
  • Wood fuzzies – raised timber fibres


What it looks like:

Here’s an example of a deck with raised timber fibres or ‘wood fuzzies’ as they are commonly known.


What are the causes?

  • High moisture content
  • Exposure to extreme temperature changes
  • Improper coating/sealing of the timber

How to prevent Kwila from cupping, warping, splitting and raised fibres with Dryden:

Regulating your Kwila deck’s moisture absorption and release rate is the key to avoiding or minimising damage from raised fibres, warping, cupping and splitting.

Dryden OilStain is one of the best defences against this type of damage because it deeply penetrates the timber and delivers exceptional water resistance and moisture management.


How to restore Kwila from cupping, warping and splitting:

If your Kwila deck shows signs of cupping, splitting, warping or raised fibres, you’ll need to repair the damage and ensure it doesn’t happen again.

  • Prep with LiquidTimberClean: To do this, first, find out what the existing finish is and reapply it after giving it a good clean with LiquidTimberClean.
  • Sand (if needed): In some cases, Liquid TimberClean won’t be enough and you would need to sand the timber to about 150 or 180 grit for better results.

This is especially true when dealing with raised fibres. The sanding process would be relatively easy with a reed side-down deck. However, decks with the reed side up might require more effort due to the intricate grooves.

  • Recoat: After finishing prep work, apply Dryden OilStain for a clear finish, or combine our OilStain with Dryden Colourtone+ for a stained finish.


Does Kwila warp easily?

Even though Kwila is denser and more durable than other decking species like Radiata pine, warping can still happen due to exposure to the elements, lack of maintenance and absence of a timber protector like Dryden OilStain.

2. Weathering

How to identify: Discolouration/ colour fading is the biggest giveaway of a weathered deck.


What causes the weathering of Kwila?

Your Kwila deck experiences wear from constant exposure to sun, rain, and wind, causing the timber fibres to erode gradually. This leads to a decline in both colour and texture.

In New Zealand, where the sun is intense and UV rays are strong, this weathering process on your Kwila decking can increase significantly.


How to restore Kwila from weathering with Dryden:

Add Dryden Colourtone+ to Dryden OilStain and apply to your weathered Kwila deck to bring it back to life! Dryden Colourtone+ provides enhanced UV protection and adds more colour to your deck.

3. Silvering

How to identify:

The rich, reddish-brown of Kwila fades away and is replaced by silvery grey. Timber of all species undergo this natural silvering process caused by the sun’s UV rays.


What are the causes?

Coloured timber extractives are washed out (leaching), and the Kwila structures get damaged by sunlight (photodegradation).

How to restore Kwila from silvering with Dryden:

There’s no natural way to reverse silvering, but you can give your Kwila deck a fresh coat of OilStain combined with Colourtone+, a pigmented tint that adds colour and an extra layer of UV protection.

Colourtone+ comes in over 37 colours, so you can find a shade similar to Kwila’s original colour.

  • Prep: Give your deck a deep clean with Dryden LiquidTimberClean and gently wash off using a garden hose.
  • Recoat: Dry and recoat with two coats of OilStain and Colourtone+ combined.


How long does Kwila take to silver?

Six to 12 months is the standard time before a Kwila deck can show signs of silvering. However, depending on the deck’s exposure to various weather elements, this can be accelerated or delayed.

For instance, decks in coastal areas with high humidity and strong sun exposure may silver faster. Meanwhile, in milder climates, this process could be slower.

4. Mould and lichen development

How to identify:

If dark spots or green patches appear on your Kwila deck, this suggests the presence of mould or lichen.


What are the causes?

Mould, lichen and moss result from damp and humid conditions, as these contaminants thrive in moisture and warmth.


How do you remove lichen from Kwila decking?

Clean with Dryden LiquidTimberClean; mix the product with equal parts of water. Apply it from the bottom to the top of the deck. Allow it to sit for 15 minutes. Keep the surface wet by spraying water. Gently wash off using a garden hose. Don’t waterblast, as this can remove the existing coating.


How to restore Kwila from mould and lichen development with Dryden:

Use Dryden OilStain after deep cleaning with Dryden LiquidTimberClean. The OilStain contains fungicide, reducing the risk of mould and lichen growth.

Apply Dryden OilStain on its own for a clear finish, or add Dryden Colourtone+ for a stained effect.

Recap of Restoring Kwila Decking

  • Kwila is a premium decking material known for its high density and durability.
  • Without proper maintenance and high-quality decking oil to protect it, your Kwila deck will eventually show signs of:
    • Cupping, warping, splitting and raised fibres
    • Weathering
    • Silvering
    • Growth of mould and lichen
  • These issues are caused by weather exposure, moisture retention and general wear and tear over time.
  • Dryden LiquidTimberClean is a specialised timber cleaning product to prepare decks for restoration.
  • Dryden OilStain is a deeply penetrating decking oil that helps restore Kwila decks with its water-resistant properties.
  • Dryden Colourtone+ is added to OilStain to add colour and UV protection.

This ultimate guide to Kwila deck maintenance has more detailed, step-by-step instructions on applying our products. Visit your local Dryden reseller and get started on your Kwila deck restoration project.