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When choosing external timber cladding, it pays to understand the durability class of different species. This will help you separate hardy species from those which are not suitable for outdoor use, whittling down your choices to make your final selection a whole lot simpler. At EcoChoice, Larch wood is one of our most popular timbers, but is it the right durability class for cladding? Find out in this guide.

What Are Durability Classes?

Durability class refers to how well timber can resist rot and insect infestation. Essentially, how well will your timber species withstand external threats? This will dictate the suitability of your timber for different applications, including timber cladding.

Class 1 is the highest level of durability, while Class 5 is the lowest. For cladding, we recommend a durability class of 1-3.

UK and European Larch Durability Class

Both UK and European Larch timber fall under the umbrella of durability class 3, otherwise known as moderately durable. This gives both timber species the green light for external cladding – good news!

You can expect a lifespan of around 10-15 years from UK (possibly slightly longer) from European Larch when used externally. As it is a durability class 3, we would advise that your lower cladding boards do not come into contact with the ground, as they are more susceptible to rot if they become wet.

Want to extend the lifespan of your Larch? Whether British or European, you can preserve Larch wood with treatments and maintenance. Our top tips include:

  • Apply a suitable wood preservative to protect against rot and fungal decay.
  • Ensure good airflow behind cladding to reduce trapped moisture.
  • Install at least 150mm above ground level to avoid rot.
  • Regularly inspect and clean the wood to remove debris and algae.
  • Reapply treatments every few years based on product guidelines and exposure levels.

For more guidance on installing and maintaining your Larch timber cladding, check out the TDCA’s timber cladding design considerations.

Does Weathered Larch Cladding Lower Durability Class?

The weathered look of Larch can be an architectural design point. Untreated, your timber cladding will take on a silver hue for a rustic aesthetic which blends perfectly with the British landscape. Weathered Larch cladding should still see a lifespan of between 10-15 years but left to the elements, it is unlikely to last much longer.

Find UK and European Larch at EcoChoice

You have got to grips with Larch’s durability class, now it is time to make a choice on whether it is the right wood for your cladding project.

Ready to place an order? We can help. At EcoChoice, we have a wide range of independently certified Larch timber sourced from responsibly managed forests. Reach out to kickstart your project and order UK or European Larch timber cladding.

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Larch cladding durability classes

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Our timber experts have years of experience and will be able to match the perfect species to your project, as well as provide a quote for sustainable timber at highly competitive prices.

Frequently asked questions

Do you supply timber for domestic uses?

Yes, we supply timber for domestic applications as well as commercial and public constructions. From garden decking to shed cladding, we will be happy to supply smaller deliveries for home use.

Is your timber FSC-certified?

Yes, all timber we supply is FSC or PEFC certified and sourced from independently verified responsibly managed forests. If we can’t find your request in FSC/PEFC certified timber we’ll suggest an alternative that is certified or clearly note that the offer is minimum EUTR.

Where does EcoChoice deliver to?

EcoChoice delivers to construction sites, warehouses and homes across the UK, as long as there’s access and unloading for our trucks.

What are the best timber species for exterior use?

There are many different timber species suitable for exterior use and which is the best for your project depends on your requirements. In general, though, we recommend EkkiGreenheartOpepe and Oak for heavier civil/marine uses. For intermediary external use such as decking, where the timber needs to be both strong and durable but not on the same level as civil engineering (bridgespiling, etc) we usually supply CumaruIpe, Jatoba, and Balau. And for the lighter exterior use where the timber is non-structural such as cladding, we deliver CedarLarchThermowood and others.

Which timber is the most durable?

Durability Class 1 timbers are the most durable. This of course depends on the use (hazard) class they’ll be in service for. For direct ground and water contact such as sleepers, fenders, marine piling, etc, Ekki and Greenheart are known to be the most durable timbers available. For decking and cladding where there’s no direct ground contact (use class 3) there’s a much wider range of timbers such Larch, Cedar, Thermo modified Pine or Ash and others.

What’s the best timber for internal cladding?

Internal cladding, where your timber is not in ground and not exposed to the elements can be classed as either use-class 1 or 2 – in which case most timbers will meet this durability criteria. That is not to say they’ll be the best, since internal environments have lower humidity (moisture) levels than outside. So in these cases, it’s best to go for a kiln-dried timber cladding board as these are more stable and delivered already in lower MC (moisture content) than the usual fresh sawn timbers sent to external applications. A word of caution – as timber reacts to variations in moisture, it’s best to avoid cladding any areas inside your bathroom.

How can I make decking less slippery?

The first thing is to ensure your deck boards are kept clean from leaves and other debris which will, over time, cover the surface and make it more slippery. Grooved boards can be used to improve grip if installed and used perpendicular to traffic, so especially useful in narrow passages and footbridges. Lastly, you can add our Grip-Choice strips: these are a mix of epoxy with aggregates that add gripping ridges to your deck area. Gripchoice is an easy way to make decking less slippery and safer, especially over large areas or where there’s high traffic. We can pre-install Grip-Choice strips for your decking before delivery or ship the strips separately to add to your existing deck’s grooves as a retro-fit solution.

What wood machining services do you offer?

We can offer planing, sawing, drilling and profiling of rough-sawn wood to any profile you require: from handrails to large port fenders.

Can you supply pre-drilled timber?

Yes, we will be happy to provide pre-drilled timber which is tailored to your needs for quick installation, thus saving you valuable time on site.

What cladding profiles do you supply?

We provide a wide range of cladding profiles, including tongue and groove, featheredge and shiplap. You can check the standard profiles here – but we can also match or custom make profiles to suit your specific needs.

Does timber change colour?

Yes, timber is well-known for changing colour over time. Some species can darken quickly right after installation, and like most untreated wood will eventually weather to a beautiful silver-grey. Interior timber is less likely to change colour (depending on conditions), and timber can be stained, painted or treated with UV-resistant oils to reduce colour change.

Do I need to treat exterior timber?

Some timbers such as Oak and Ekki, can withstand the strains of exterior use without any treatment. However, to extend the lifespan and maintain the aesthetic of your wood, we do recommend treating your timber with stains and oils. Pre-treated timber, such as ThermoWood and OrganoWood, are low-maintenance options which are more durable, but can have their life service extended by applying a clean and stain maintenance schedule.

Do I need to treat interior timber?

Depends on what area the timber is being used. For floor joists and timber rafters, it is common to see timber treated, or least very well kiln-dried. Other uses such as flooring may benefit from varnishing while internal timber cladding for decorative purposes shouldn’t require any treatment other than if you want to change its colour with different types of stains or oils.

Where are you based?

We’re based in Cambridge, UK, and coordinate multiple sawmills all over the world to manufacture your order. We then organise delivery with a range of hauliers so that your orders gets to your site on time.

What are the usual decking sizes?

Timber decking is usually 21x140mm or similar. For heavier applications where there’s more load and traffic, we deliver 35 or 45mm thick boards (such as Hastings Pier). Narrower boards are also possible: 95-90mm is a standard width – but we can manufacture whatever size you require.

What are the usual cladding sizes?

Typical cladding section sizes are 18×95 and 18x145mm although we can always custom make a section to suit your project’s design requirements. That includes waney edge boards in Oak or Chestnut as well as extra wide 195mm boards.

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Marinella Li

Always helpful! One of our valued TDCA DeckMark and CladMark accredited supplier members which means their quality procedures are routinely audited and stand up to scrutiny giving you extra peace of mind.

5

Janet Sycamore

Having needed the supply of cladding, decking boards and other specified timbers through out the year Eco choice have been very helpful in sourcing the specified timbers and quantities required at a very competitive price.

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Tim Saunders

Great quality, service and price. A pleasure to deal with. I would highly recommend Eco Choice.

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Emma Hurrell

Fantastic company- Mike and the team are the best in the business- worked with them for many years.

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Always reliable and quality products, easy to deal with company.

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Stone Zone

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Average rating on Google Reviews

  • 6 years ago

Having needed the supply of cladding, decking boards and other specified timbers through out the year Eco choice have been very helpful in sourcing the specified timbers and quantities required at a very competitive price.

Tim Saunders

  • 3 years ago

Always helpful! One of our valued TDCA DeckMark and CladMark accredited supplier members which means their quality procedures are routinely audited and stand up to scrutiny giving you extra peace of mind.

Janet Sycamore

  • 2 weeks ago

Good quality, great service, fast delivery!

Marinella Li

  • 6 years ago

Always reliable and quality products, easy to deal with company.

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