Which type of wood is best for timber decking?

The most common material used for decking is a pressure-treated softwood as it is readily available and cost-effective. Builders’ merchants will generally stock at least one softwood decking board with some now stocking an anti-slip version as well. While softwood is the most common option there are alternatives on the market, which may be better for your project.

Hardwood

The main advantage that hardwood holds over softwood is its longevity. While most softwood timber decking boards have up to a 15-year in service life expectancy, hardwoods such as Yellow Balau can be expected to last for up to 50 years, and in some cases longer. They are far more durable and hard-wearing than softwood products, so consequently come at a larger cost.

Hardwood timber is generally considered higher quality than softwood. It’s more colourful and natural timber appearance makes it very popular for decking. The cost of hardwood varies significantly depending on the species, profile size and timber certification you are looking for, but as a very rough rule of thumb, you will be looking at around three or four times the price of softwood.

Requiring minimal maintenance and well suited to a wide variety of projects, hardwood decking is an investment to seriously consider for your decking.

ThermoWood

ThermoWood is available in a variety of timbers, including ThermoPine (softwood), ThermoIroko and ThermoAsh (hardwoods). The process of creating ThermoWood involves heating the timber in a low oxygen environment to alter its chemical structure and increase its durability. This is particularly effective for softwoods and can be a more environmentally friendly way to increase the life expectancy than using a chemical treatment.

The thermal process also increases the stability of a decking board. Invisible fixing systems can be used on the ends and sides of the board as the board will expand and contract less than normal. The biggest downside of using a heat treatment is its effect on the strength of the board. Some estimates suggest thermal treating reduces the overall strength of the board by 30%. The price of ThermoWoods varies depending on the species and sizes, but the costs are often comparable or slightly higher than hardwoods.

Accoya®

Accoya® is produced from fast-growing and sustainably sourced timber which undergoes a chemical process to modify the timber completely. The resulting timber is incredibly stable and comes with a life expectancy of 50 years when installed above contact with the ground and an amazing 25 years when installed in freshwater or in direct contact with the ground. In addition, the timber is virtually rot proof so can be used in virtually any environment. Currently, Accoya is available in a limited selection of lengths and comes in at a high market price, however for the investment you get a phenomenally stable and long lasting timber.

Medite® Tricoya®

Medite Tricoya is produced using wood fibres that have undergone the same chemical treatment as Accoya. This creates a panel product which is extremely stable and durable with a 60-year expected life cycle. As with Accoya, Medite can be in water contact with very few negative effects. The biggest downside of using the wood fibre is that the panels are susceptible to abrasion when walked on. Anti-slip coatings are recommended to give you an incredibly safe and hard-wearing product fit for a wide range of environments. Panels can be machined to smaller lengths or supplied as full panels to suit the area you are working with. This makes Medite truly is a flexible option when considering decking. As with Accoya, the cost of Medite will be towards the top end of the spectrum.

As you can hopefully see there are plenty of options to consider when deciding which timber to choose for your decking. You will need to consider the budget, site considerations such as wet or shaded areas and the appearance of the timber you are looking for.

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Should I use composite decking in my garden?

You know you would like to invest in new decking for your garden but which should you go for: composite or timber decking? There are a number of differences between them, from the material used to how safe they are to walk on when wet.

Composite vs timber

So what is the difference? Composite decking is usually composed of wood from sawdust mixed with plastic and moulded to resemble a deck board. The Timber Decking and Cladding Association (TDCA) has received a number of reports of poor composite performance, though these appear to be limited to a particular type of ‘cheaper’ hollow form board. Concerns have also been raised about new decking boards being fitted over existing substructures which are often unsuitable for wood plastic composite. Manufacturing composite decking is complex, so results will vary. If you decide to go ahead and use composite decking, make sure you are going for the best product you can find.

Timber decking is made from a solid, natural, renewable product: wood. Gripsure non-slip decking is made using high-quality, commercial-grade Redwood timber. And this is just the first of many differences:

Safety

One of the most important differences is that composite becomes slippery when wet whereas Gripsure anti-slip timber does not. Our innovative decking includes a non-slip treatment. This means they stay safe even when the decking is covered with surface water, algae, fallen leaves or even ice. All our products are independently tested with Gripsure also offering a 15-year non-slip guarantee, giving you peace of mind that your family are safe from the risk of accidents in poor weather.

Value for money

Many people assume that composite decking will be cheaper than solid timber decking. In fact, to get a reasonable quality composite decking you would need to pay about the same as for a hardwood timber deck. Cheaper composite options are likely to be very poor quality and are unlikely to last, so would not be good value in the long run. If you are on a budget, a softwood timber decking would be a better choice than a cheaper composite. If you have a bigger budget, you could get hardwood timber decking for the same price as the most expensive composite.

Long-lasting look and structure

Many people go for composite decking as they believe it will be a low-maintenance addition to their outdoor space. You may be surprised to hear that this wood and plastic blend needs more regular pressure washing than timber. We recommend a pressure wash to our catalogue of Gripsure products every 12 months. With composite, moisture can seep through the outer plastic layer down to the wood fibre causing it to swell, which over time can lead to holes forming in the surface of the boards. In comparison timber swells much less, reducing any structural damage that might occur. If you are determined to go for composite, do your homework and make sure you are confident you are getting the best decking you can find. We would always recommend timber as the best option for any garden. If you want safety without compromise, value for money and stunning decking in your outdoor space, then anti-slip timber is the answer.

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Gripsure performance warranty and strength graded decking

Gripsure introduces a revolutionary performance warranty for their non-slip decking range.

What is a performance warranty?

Gripsure have introduced a revolutionary performance warranty for their non-slip decking range. You can now be assured your decking will retain its non-slip performance for 15 years, guaranteeing you complete peace of mind. No other company offers this level of performance warranty.

Some decking products will give you an initial slip resistance i.e. what they achieve on day one, before they are even laid. But at Gripsure we think this is irrelevant. Having invested in our product, we think you should have peace of mind for the future. What you really need to know is “how long will my decking remain non slip and to what extent?”

The aim of this warranty is to ensure that our customers have a clear understanding of how well the decking will perform, and what that means in practice.

Find out more about our performance warranty

How is anti-slip measured?

There is a British Standard (BS7976) that uses a pendulum test to measure the slip resistance of a pedestrian surface (pendulum test value – PTV).

The UK Slip Resistance Group have then taken these figures and issued a guideline as how these results are practically interpreted i.e. how safe is a decking board when it achieves a certain PTV rating. A value greater than 65 is defined as an “extremely low” potential for a slip.

PTV range Potential for slip
0-24 High
25-34 Moderate
35-64 Low
65+ Extremely low

What is strength grading?

Timber is a natural product and as such is inherently variable, not only in terms of appearance but also strength. Grading is used to give a basic indication of the strength of individual pieces of timber and allows for the selection of the appropriate strength grade for expected loads.

How is timber graded?

Timber can be graded mechanically or visually depending on what the material is used for, in the case of decking it is done visually. Graders look for structural issues within the timber, for example size and location of knots, twists, splits, twists and shakes. From this the decking boards will be labelled as Ungraded, C16 or C24, depending on the quality of the board.

Why should I choose graded decking?

Graded deck boards have several advantages when planning a project. Firstly higher grades are capable of handling higher uniformly distributed and point loads with minimum deflection or movement of the boards. Secondly, wider joist centres can be used for graded timbers which can aid in the design of the deck and also reduce the cost of the subframe. Alternatively, a thinner board could be used on the original centres, again reducing the cost of the project.

Graded deck boards have several advantages when planning a project. Firstly higher grades are capable of handling higher uniformly distributed and point loads with minimum deflection or movement of the boards. Secondly, wider joist centres can be used for graded timbers which can aid in the design of the deck and also reduce the cost of the subframe. Alternatively, a thinner board could be used on the original centres, again reducing the cost of the project.

Some good examples of projects benefitting from graded boards:

  • Raised Walkways and Bridges: Graded boards allow for wider joist centres to be used which reduces installation time and subframe costs.
  • Balconies: Thinner boards and wider joists reduce the weight of the decking when securing the balcony to the building, as well as giving you flexibility in matching up with threshold heights.
  • Commercial Spaces: Wider spans can be used without fear of the boards deflecting and causing trip hazards, keeping costs lower whilst ensuring health and safety requirements are met.

Timber treatments

Most softwood timber products should be supplied pressure-treated to give the product the longest possible ‘in service’ life, but what does this mean?

What is pressure treatment?

Pressure treatment is essentially the process of impregnating timber with a chemical preservative designed to protect the timber against fungal attack, rot and decay. These preservatives can be categorised into three broad groups: water-borne, oil borne and light organic solvent, however the application process is generally the same for each as outlined in the diagram below:

Use classes

Pressure treated timbers are split into several different ‘classes’ which are created by using a different solution strength during the treatment cycle. It is important to make sure you pick the correct class for your specific requirements to ensure long lasting performance. As a very brief overview the main classes are:

Class type Class description
Use Class 1 Internal timbers that will permanently be dry
Use Class 2 Class description
Use Class 3 External timbers used above ground and exposed to the weather
Use Class 4 External timbers in direct contact with the ground and/or fresh water

Depending on the class you select you will have a different projected ‘in service life’, this basically means the expected life-span of the timber if it is installed correctly. For example, most decking will be treated to Use Class 3 and come with a 15-year in-service-life.

Colour

Pressure treatment will generally leave the timber with a green or brown colouring depending on the specific chemical being applied, however over time the timber with weather to a silver/grey appearance regardless of its original colouring or treatment. This means that any timber used, regardless of whether you use multiple treatment systems will eventually be indistinguishable.

End grain preservative

The chemical preservative will only penetrate the top layers of the timber, meaning there is a section in the centre of any board that won’t be impregnated. This is absolutely fine if you are installing the timber without any cutting or drilling, however if you do intend to break the treated timber it is essential to apply an end grain preservative to keep the treatment ‘sealed’.

Environmental impact

The chemical compounds used in pressure treated timber are constantly being developed to ensure they are safe for both the users and the environment around them.

References:
https://www.selwood.com/climbing-frames/why-not-pine.html
http://www.tanalisedtimber.co.uk/using-tanalised-timber/use-class-information
https://en.wikipedia.org/wiki/Wood_preservation

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The Resurgence in Timber Decking

Over the last 30 years, timber decking has firmly established itself as a quick and aesthetic option for external landscaping. With a meteoric rise thanks to the TV makeover programmes in the 1980s and then the introduction of alternative materials in the last 10 years, the traditional timber deck has recently had to look at its shortcomings and adapt to market demands for safety, performance and quality.

As a material, timber with its sustainability, natural durability and timeless looks, remains a natural choice for architects today, and many are now coming back to specify timber for its simplicity, ease of installation and enhanced safety.

Safety

The biggest barrier that timber has had to overcome is its propensity to become very slippery, very quickly in the UK climate. And for commercial designers, the need for safety and peace of mind over the lifetime of the project is paramount. Timber is an attractive substrate for algae to quickly take hold – the timber surface retains moisture and therefore the can remain damp long after the rain has gone. Repeat this cycle many times over the season and you have perfect growth conditions for algae. Of course this algae growth can be physically removed, but particularly on commercial sites, this incurs additional time, costs and even logistical difficulties.

The solution lies in specifying a non-slip timber decking board. These boards use an unobtrusive aggregate treatment to give a long-lasting slip resistant finish. And they can be independently assessed to a slip resistance test BS7976, providing an objective measure to help rate the boards. This test is available as an initial measure of the new board, but also now as a measure after 10 years – an “extended performance guarantee” of how well the anti-slip properties of the board will last.

Timber Performance

Great developments have been made in the treatment of timber since those early days of arsenic-based chemicals. And by using the latest micronised copper technology softwood timbers can be treated for up to 30 years ‘in-service-life’. By using the Use Class Tables as defined in British Standard BS EN 335, there are 5 “use classes” to which timber can be treated. For timber decking it depends on the application i.e. where it is being used as to what will determine the level of performance expected from it. For example, if the timber is in direct contact with either the ground or freshwater it should be treated to Use Class 4, but where the timber is above the ground Use Class 3 applies.

Make sure the timber for your deck is treated to the appropriate Use Class, not just for the deck boards but for every element of the structure.

Quality of Timber

When looking to specify timber decking, the application should determine the most suitable species, grade and finish that is chosen.

Softwood timber is extremely popular, versatile, and readily available from many sources. Scandinavian timber is great value for money, and provides a good balance between quality of slow-grown timber stock versus cost. It comes in several grades, but the most frequently specified ones are Fifths and Unsorted.

Hardwoods are another option to consider, particularly for marine/freshwater applications, and with many hardwoods having an expected in-service life of 40 years plus, the higher initial cost can be a good investment when taken across its whole lifetime. And many hardwoods will now come with a fully certified “chain of custody” to ensure they are a safe environmental choice.

Sustainability

Which brings us to the use of timber for decking compared to other materials. By specifying either FSC or PEFC certified timber, you can be sure the decking has come from a sustainable forest and will be environmentally sound. Being a natural grown material, the harvesting, production and treatment of timber also provides sustainable employment, so by choosing timber over other “plastic” based materials goes beyond just the product – you help sustain the whole supply chain.

In conclusion

Timber decking is a naturally grown material that is wholly sustainable, and given the current range of finishes, species available and its performance characteristics, it is a material that is more than fit for purpose for buildings of the future. Its versatile, safe and extremely durable. Throw away any prejudices about slippery timber decking and specify a product that is timelessly beautiful, renewable and measurably safe!

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If you have any questions or would like more information, get in touch with one of our friendly team.