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There are two ways where timber and stain come together in the same sentence. One is when you buy timber stain at your local timber merchant with a view of adding colour and durability to your cladding and decking. The other is tannin staining on surrounding surfaces, in which the areas around your timber cladding become discoloured by being in close contact with the tannins released by the timber as it weathers naturally. If you want to understand more about tannin staining and how to reduce it, read on.

Why Does Timber Look Stained?

Timber is a natural material but its structure is pretty complex, with each plank of wood made up of numerous natural cells and fibres. One part of timber structure is in liquid form, known as extractives, or even essential oils. These extractives are usually found in the heartwood of the timber but can spread to other layers of the wood and surrounding surfaces.

One extractive in particular is to blame for the staining issue and discolouration of wood and surrounding surfaces. We call this extractive “tannin”, and it is not uncommon for it to leach through and out of the wood, particularly when the timber is used for an exterior application. Rain pulls up the tannin and allows it to discolour certain areas of the timber, as well as nearby surfaces. If your concrete wall has a reddy-brown stain near to your wood, you are seeing the tannins in action.

How to Prevent Timber Staining Other Materials

If you are concerned about timber staining surrounding building materials, particularly those which are absorbent, it is smart to let the wood weather before placing them side-by-side. During the early stages of the weathering process, when timber is subjected to open air, wind, sun and rainfall, is when the tannins are most likely to leach onto the surface of the cladding boards. Once the boards have weathered and thus released their tannins, they are less likely to stain.

It is also best to plan ahead for staining by only using stainless steel fixings which will not be corroded by the tannins, and avoiding close proximity with concrete. Clever design can channel water with high timber tannin content away from other surfaces. This is tricky, but it is worth it for low-maintenance, stain-free construction!

How to Prevent Tannin Staining on the Timber

As well as staining surrounding materials, tannin can rise to the surface of timber cladding and cause coloured marks on the wood itself. To prevent this, you can apply tannin-resistant primers and waterproofing sealants.

Tannin discolouration can also occur when stains are applied unevenly, causing “tannin pull”. The tannins rise through both the timber and the stain, and end up lying on the surface. To reduce the chance of this happening, call in an expert to stain your wood and only try it yourself if you do not mind running the risk.

If you go ahead and stain your wood and cause tannin pulling, or you see tannin discolouration from water exposure, sand down the timber with a fine sandpaper until the surface is one even colour again.

Learn More About Timber

At EcoChoice, we supply timber for cladding, decking and more, with a wide range of sustainably sourced species available. We are timber experts and part of our job – when we are not delivering timber – is to help you maintain your wooden constructions. For more information on timber maintenance or to learn which species is right for your project, check out more on our blog. For advice specific to your situation, feel free to get in touch with our team today and we will be happy to help.

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Timber cladding stains

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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.

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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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Average rating on Google Reviews

  • 9 years ago

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

Malcolm Coury

  • 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

  • 9 years ago

Wonderful guys!

Nicola Edmead

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