Pressure-treated timber is the best choice when a lower purchase price, the feel of timber, and the ability to build it yourself are key factors. Aluminium is usually a better choice when you prioritise a long service life, dimensional stability, and as little ongoing maintenance as possible.
The difference, therefore, isn’t just about how much the balustrade costs when you build the deck. Timber requires regular maintenance and changes with the weather and age, while aluminium requires less ongoing maintenance and retains its appearance more consistently over time.
Here, we compare the materials based on maintenance, lifespan, cost, and use, so you can decide which balustrade is best suited for the location and how much effort you want to put into it going forward.
What is pressure-treated timber?
Pressure-treated timber has been treated so that the timber preservative is forced into the timber, rather than simply sitting on the surface.
- This is protected
- The treatment makes the timber significantly more resistant to rot and insect damage than untreated pine.
- What still changes
- The timber can still crack, warp, turn grey, and become slippery when it has rained. The timber preservative does not protect the surface from the weather and the sun.
- Here's what you need to do
- The balustrade still needs to be cleaned and may need to be oiled, painted, or sanded, depending on the finish you want to maintain. The timber preservative extends its lifespan, but does not make the timber maintenance-free.
How long does a pressure-treated balustrade last?
A pressure-treated balustrade can often last about 10–15 years, but its lifespan varies depending on the specific parts and is affected by the design, weather conditions, and how regularly the timber is maintained.
Top rails, exposed end grain, joints, and post bases are particularly vulnerable because moisture can more easily become trapped there. When comparing timber with an aluminium balustrade you therefore need to consider both maintenance and how exposed the location is, not just the purchase price.
| Part of the balustrade | Approximate lifespan | What affects it |
|---|---|---|
| Top rail | 8–12 years | Sun, rain, and surface treatment. |
| Balusters and slats | 10–15 years | Ventilation and drainage. |
| Posts above ground | 10–15 years | Joints and areas where water collects. |
| Posts in contact with the ground | 8–10 years | Moisture exposure and contact with the ground. |
| Fixings | Varies | Material selection, moisture, and risk of corrosion. |
How does the maintenance of pressure-treated timber differ from that of aluminium?
Pressure-treated timber needs regular cleaning and surface treatment, while powder-coated aluminium normally needs much less ongoing work. Timber, on the other hand, has a lower purchase price and can be easier to work with and repair yourself.
| Property | Pressure-treated timber | Powder-coated aluminium |
|---|---|---|
| Purchase price | Lower | Higher |
| Surface Treatment | Needs to be done regularly | Normally, no recurring surface treatment is required |
| Sanding | May be needed when the surface becomes worn | Usually not |
| Service life | Usually around 10–15 years | Could be 25 years or more |
| Appearance over time | The timber may turn grey, fade, and change | The colour and surface change less |
| After rain | The top rail may become slippery when wet | The surface is less affected by moisture |
| Dimensional stability | May crack or warp | It retains its shape better over time |
The main difference, then, lies in the ongoing maintenance required. With timber, you need to plan for surface maintenance throughout the balustrade’s lifespan, while aluminium mainly needs to be cleaned when it gets dirty.
Which finish suits pressure-treated timber?
Oil is a good choice when you want to preserve the natural look of the timber and avoid a coat of paint that might peel. A timber stain adds colour while allowing the grain to show through, while a solid paint provides a more opaque finish; you can also leave the timber untreated if you’re okay with the surface turning grey over time.
- Oil
- Penetrates the timber and keeps it supple. The timber turns grey more slowly and needs to be treated more often, but the surface does not form a layer of colour that can flake off.
- Timber stain
- Gives the timber a tint while allowing the grain to remain visible. The surface wears more evenly than opaque paint and is easier to touch up.
- Opaque paint
- Provides an opaque coat of paint and protects the surface from sunlight, but the coat may begin to peel over time. Before repainting, the surface usually needs to be cleaned and, if necessary, sanded.
- Untreated
- The timber can be left to weather naturally. The preservative still protects against rot, but the surface changes with exposure to the elements and age and may become rougher over time.
When is a pressure-treated timber balustrade the right choice?
Pressure-treated timber is particularly well-suited when the natural look of timber, a lower purchase price, or the ability to build it yourself are more important than the need for as little ongoing maintenance as possible.
When timber is part of a house's aesthetic
In older homes or on decks where timber is already the dominant material, a timber balustrade may be a better visual fit and make it easier to maintain a cohesive look.
When you want to build and customise it yourself
Timber is easy to cut, work with, and customise using standard tools. It is therefore a good choice for anyone who wants to build the balustrade themselves and is willing to accept that the surface will require maintenance even after installation.
When the purchase price is a major factor
Pressure-treated timber typically has a lower purchase price than a ready-made aluminium balustrade system. The advantage is greatest when you are also willing to spend time on future cleaning and surface treatment.
How do you choose between pressure-treated timber and aluminium?
Consider the purchase price, future maintenance, the site’s exposure to the elements, and how much you want to be able to do yourself. Regardless of the material, the balustrade’s placement and design must provide adequate protection against falls. Regulations and requirements may vary depending on where the structure will be installed. Check the current guidelines from your local authority or the relevant building regulations authority.
Before you choose materials
Consider cost, maintenance and site conditions
-
Look beyond the purchase price
Don't just compare the cost of the balustrade when you build it. Also take into account future surface treatment, labour, repairs, and how long you expect the structure to be used.
-
Estimate how much maintenance you actually want to do
Pressure-treated timber needs to be cleaned and treated on a regular basis. Aluminium is a better choice if you want to reduce ongoing maintenance and mainly clean the balustrade when it gets dirty.
-
Check how exposed the site is
A shady and damp location is more demanding on timber than an open and well-ventilated area where the balustrade can dry quickly after rain. The more exposed the location, the more important the material’s resistance to moisture and the elements becomes.
-
Assess the risk of falls and the entire balustrade structure
Drop height, placement, openings, fixing, and the balustrade’s other design features must be evaluated together. The choice of material is only one part of a safe balustrade solution.
-
Consider whether the materials can be combined
An aluminium frame with a timber top rail can be a compromise when you want to maintain the feel of timber where your hand touches the balustrade but reduce the maintenance required for the other parts.
-
Choose fixings to suit the material
Fixings and hardware must be suitable for both the balustrade structure and the environment in which it will be installed. For pressure-treated timber, it is especially important to choose fixings with the proper corrosion resistance.
Brief summary
Choose timber when the purchase price, the feel of timber, and the ability to build it yourself are the most important factors. Choose aluminium when you prioritise lower maintenance and greater dimensional stability over time.
Help choosing materials
Not sure whether timber or aluminium is right for you?
Start by considering how much you want to spend on maintenance, how exposed the location is, and the look you’re going for. If you’d like to compare the options further, you can check out our balustrades or get help from customer service to make your choice.
What are some common questions about pressure-treated balustrades and aluminium?
The choice often comes down to more than just the purchase price. Here are brief answers to some common questions about maintenance, surface treatment, and the differences between timber and aluminium.
Which type of balustrade requires the least maintenance – timber or aluminium?
Aluminium generally requires minimal ongoing maintenance. Powder-coated aluminium mainly needs to be cleaned when it gets dirty, whereas pressure-treated timber needs to be inspected and refinished periodically.
Is pressure-treated timber cheaper than aluminium?
Pressure-treated timber usually has a lower purchase price. However, the total cost over time is also affected by maintenance, repairs, and how long the balustrade lasts.
Can pressure-treated timber be left untreated?
Yes. The preservative still provides protection against rot, but the untreated surface turns grey and changes with exposure to the elements and age, and may become rougher over time.
When can you paint or oil new pressure-treated timber?
Wait until the timber has dried sufficiently. Freshly pressure-treated timber may contain a lot of moisture, which impairs the ability of paint, stain, or oil to adhere to the surface.
Can you combine timber and aluminium in the same balustrade?
Yes. An aluminium frame can be combined with a timber top rail. This way, you retain the feel of timber where your hand touches the balustrade, while maintenance is focused primarily on the timber parts.
Which fixings suit pressure-treated timber?
Choose fixings with sufficient corrosion resistance for pressure-treated timber and the environment where the balustrade will be installed. The wrong material can corrode and weaken the fixings over time.
What material is best if I want to build the balustrade myself?
Timber is often easier to cut, work with, and customise using standard tools. It may therefore be a good choice for DIY balustrades if you are also willing to accept the future maintenance it will require.
