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In the world of sustainable timber, the terms ‘heartwood’ and ‘sapwood’ come up a lot. If you are not a timber expert, this can be quite confusing and make the search for the right timber products for your project even more challenging. To clear things up and get rid of the jargon, our EcoChoice team has sat down to clarify what heartwood and sapwood are, the difference between the two, and how they are relevant to your outdoor applications.

What is Heartwood?

Heartwood is the central part of the tree trunk. This is the strongest  part of the tree, surrounded by the living outer layers (sapwood). When exploring ‘what is heartwood’, you can identify it by looking for the darker colour timber in the cross-section of a tree trunk.

Typically, heartwood is much denser than sapwood, with excellent resistance to decay and impressive durability. If you are looking for the toughest part of the tree, the heartwood is where you will find it.

What is Heartwood Used for?

Thanks to the superior strength and durability of heartwood, timber is often favoured for exterior and load-bearing constructions. Common uses include:

Of course this also depends on the timber species being used. For example, Pine is going to be less suitable for these applications than a tougher, more durable hardwood timber, e.g. Ekki or Oak.

What is Sapwood?

Sapwood is the younger, outermost layer of the tree trunk which surrounds the heartwood, just beneath the bark. Unlike heartwood, sapwood plays a crucial role in transporting water and nutrients from the roots to the leaves. To spot sapwood, look for the lighter colour in the cross-section of a tree trunk, forming a ring just beneath the bark.

Sapwood is generally softer and less dense than heartwood. However, it is also more permeable, which means it readily absorbs preservatives, making it easier to treat for enhanced durability.

What is Sapwood Used for?

Because of its relative softness and ability to take on preservatives, sapwood is often used in applications where strength is less crucial, or where it can be treated for added durability. Common uses include:

  • Interior joinery, such as mouldings and trim
  • Veneers and panel products
  • Treated fencing and landscaping timbers
  • Pallets and packaging materials
  • Constructions where the timber will be protected or coated

You can use sapwood for exterior applications, such as decking or cladding, but it should be treated to the right use class before installation.

Find the Right Timber for Your Project

Knowing the difference between heartwood and sapwood is a great starting point on your journey to find the right timber, but there is a lot more to learn! If you would rather get cracking with your project, we can help save you time. Our team at EcoChoice are timber experts, and will be happy to advise you on the right timber species and products for your next project.

Ready to find the right timber for your outdoor project? Get in touch with us today.

Internal structure of timber

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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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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

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  • 6 years ago

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

Emma Hurrell

  • 9 years ago

Experts in Timber, Nationwide delivery

Joe Middleton

  • 9 years ago

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

Malcolm Coury

  • 9 years ago

Excellent service and outstanding product

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