Types of Wood Cladding Explained

Before we get to wood cladding, for those who don’t work in the construction industry, let’s look at what cladding is first.

Cladding is “the application of one material over another to provide a skin or layer… to provide a degree of thermal insulation and weather resistance, and to improve the appearance of buildings.”

Of course, at the moment in the UK, the word ‘cladding’ in the construction industry is a real watchword. After the Grenfell Tower disaster in North Kensington in June 2017 fire safety in tall buildings has been looked at closely, “The 24-storey block was clad in aluminium composite material or ACM which is now known to be dangerously combustible.”

Using wood as a cladding material offers many advantages and woods such as OrganoWood not only last a long time, weather to a pleasant grey tone, but are also resistant to fire.

Now that we have identified what cladding is let’s move on to the different types of wood cladding. Some types of timber are more durable than others.

There are five different durability classes. The durability rating is based on the heartwood only. Heartwood is the central part of trees. It is mechanically strong, resistant to decay, and less easily penetrated by wood-preservative chemicals than other types of wood.

Natural Durability Class

BS EN 350: 2016

Desired services life/years

Occasionally wet (with coating)

Desired service life/years

Frequently wet

1 – Very Durable >60 60
2 – Durable 60 30
3 – Moderately Durable 30 15
4 – Slightly Durable 15 <15
5 – Not Durable <15 <15

 

The rows highlighted in yellow will all need to be appropriately treated to extend their service life.

Principal softwood species used in the UK for cladding

Common name

Natural Durability

Class (BSEN350: 2016)

Sapwood Treatability Movement Density kg/m³ Availability
Douglas Fir
Home grown 3 – 4 Resistant Small 470 – 520 Specialist supplier
North American 3 Resistant Small 510 – 550
Larch
European 3 – 4 Resistant Small 470 – 650 Specialist supplier
Hybrid (aka Dunkeld) 3 – 4 n/a n/a n/a Specialist supplier
Japanese 3 – 4 Resistant Small 520 Specialist supplier
Siberian 3 – 4 Resistant Small or medium 680 – 700 Good
Pine
Scots Pine / European redwood 3 – 4 Permeable Medium 500 – 540 Good
Lodgepole Pine 3 – 4 Permeable Small 430 – 470 Good
Radiata Pine 4 – 5 Permeable Medium 420 – 500 Specialist supplier
Southern Yellow Pine 4 Permeable Medium 650 – 670 Specialist supplier
Spruce
Sitka Spruce / European Whitewood 4 – 5 Resistant Small or medium 400 – 450 Good
Norway Spruce 4 Resistant Medium 440 – 470 Good
Western Red Cedar
Home grown 3 Resistant Small 330 – 390 Specialist supplier
Canadian 2 Resistant Small 330 – 390 Specialist supplier

 

It is also possible to enhance the performance (durability and stability) of most of the types of timber listed above, through either chemical, biological, or heat processes.

The primary objective in modifying wood is to make them more durable (less prone to rot). This makes modified woods last longer than unmodified woods. The most commonly modified timbers for cladding in the UK are depicted below. Thermowood® mnetioned below is the registered process controlled by the Finnish Thermowood Association – we sell this and also other types of thermo modified timbers

Modification process / brand Base species Assigned Natural Durability Class Dimensional stability / movement Strength Coating performance
Thermally modified timber
Thermowood S² (190°C) Pine or Spruce 3 Improved + Unchanged Improved
Thermowood S² (185°C) Birch or Aspen 3 Improved ++ Reduced Improved
Thermowood D (212°C) Pine or Spruce 2 Improved + TBC Improved
Thermowood D (200°C) Birch or Aspen 2 Improved ++ Reduced Improved
Thermodified Frake Black Afara Improved ++ TBC Improved
OrganoWood Pine or Spruce 2 Improved ++ Unchanged TBC
TMT Ash / ThermoAsh American Ash 1 TBC Unchanged Improved
Chemically modified timber
Accoya (510kg/m3) Radiata Pine 1 Improved ++ Unchanged Improved

 

There are also hardwood species such as Oak, Iroko and Cumaru that are suitable for cladding, although due to their usually higher density and strength, special attention is needed when fixing them.

Cladding also makes a building more aesthetically appealing as we stated earlier. The tradition of using cladding to enhance the appearance of a building goes back a long way and is still universally appealing.

In Ancient Japan the charring tradition of Shou-Sugi-Ban was used for centuries to make their buildings resistant to fire, rot, insects and UV effects from the sun. The practice started in the 18th century. Buildings clad in Shou-Sugi-Ban treated cladding can be protected for up to 120 years. We have now added charred Larch to our range of cladding – with a wide choice of charring levels.

And because timber is a natural product, using wood cladding means that you are protecting your home as well as the planet. In this year of #WoodCO2tsLess, doing anything you can to help reduce the world’s CO2 emissions is an incredible step in the battle to fight climate change.

EcoChoice are dedicated to fighting global warming and to encouraging people to switch to using independently certified sustainable wood for their construction and design work.

Speak to us on 0345 638 1340 to find out how we can provide you with the exact sustainably sourced materials you need for your next project.

Let’s work together to tackle climate change #WoodCO2tsLess.

 

Tags: ,

Categories:

Timber cladding types explained

Ask Joe! Expert industry advice

Unsure which timer is best for your project?

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.

Trusted by

What our customers say about us

Good quality, great service, fast delivery!

5

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.

5

Tim Saunders

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

5

Emma Hurrell

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

5

Prem Raja

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

5

Stone Zone

4.9

Average rating on Google Reviews

  • 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

  • 9 years ago

Great service, quality products and very easy to deal with. Thank you.

Malcolm Coury

  • 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

  • 9 years ago

Excellent service and outstanding product

Cindy Dicks

Your enquiry

Name(Required)

Contact us today

Opening hours

Mondays: 09:00 – 17:00
Tuesdays: 09:00 – 17:00
Wednesdays: 09:00 – 17:00
Thursdays: 09:00 – 17:00
Fridays: 09:00 – 16:00
Saturdays: Closed
Sundays: Closed