Which cladding fixings are best?

Choosing the best fixings for your timber cladding depends on the profile, style and the orientation of your cladding boards.

Below, we explain what you need to consider when securing timber cladding to a new build or existing structure.

As with any building project where materials will be exposed to the outside elements, all metal fixings must be made from corrosion-resistant materials. After all, no one wants to see rust streaming down their property.

Timber cladding fixings, what we and the TDCA recommend

Fixings include all nails, screws, concealed support systems, bolts, and accessories. This is regardless of whether the surface is to be finished with a coating or left unfinished to weather, visible or hidden.

You should be looking at suitable metals such as stainless steel-austenitic grade, silicone bronze, high-performance coated steel, or hot-dipped galvanised (BS7371:6 min) copper. We’d suggest staying away from the likes of aluminium, electroplated steel, and brass.

What to use: screws or nails?

The common practice is to install timber cladding using ‘face fixed’ nails or screws – fixing the cladding to the timber battens behind, through the front face of the timber cladding.

If you are using softwoods, including Cedar or Larch, you can use ring shank nails where the fastener head is at least twice the shank diameter (min. 2.3mm shank diameter) or just use cut pointed screws.

If you are using hardwood such as Iroko, Cumaru or Pituca, it is best to use screws. For such dense species with a potential for splitting around fixing points, the pre-drilling of 2mm oversize pilot holes should be carried out to allow for any movement in the board that may occur after installation.

When using species with high tannin or corrosive oil content such as Western Red Cedar, Douglas Fir and some hardwoods such as Oak and Chestnut, only use stainless steel fixings otherwise the reaction to iron can cause permanent black spotting and corrosion staining of the surface.

Timber cladding fixing positioning

  • Fixings should finish flush with the timber surface. As such it is important to ensure that the cladding moisture content is around 16% at the time of installation to avoid shrinkage since this would leave fixings proud of the surface. Learn more from the TDCA.
  • Fixings length should be at least 2.5 times the thickness of the board
  • Position fixing 25% in from each side – and a minimum of 20mm from board ends
  • Where concealed fixing is required, then boards may be back fixed to counter battens or installed using a proprietary metal fastening bracket or support system. Concealed fixing systems are best used with prefabricated cladding panels.
  • On denser timber, pre-drill all fixing points with 2mm oversized holes. Pneumatic fixing guns should be used with care to ensure the timber surface is not affected by impact damage or the fixings driven below the surface.
  • For screw fixing, handheld ‘impact’ type power screwdrivers are best as these are less likely to damage the wood or the drive recess. They’ll insert the screw at optimum speed and prevent the coating burn associated with high-speed power drivers.

If you would like to find out more about our exterior timber cladding fixings, please get in touch. Call us on 0345 638 1340 – or drop us an email at sales@ecochoice.co.uk.
Images: TDCA

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Choosing cladding fixings

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.

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Good quality, great service, fast delivery!

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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.

5

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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Prem Raja

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

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  • 9 years ago

Experts in Timber, Nationwide delivery

Joe Middleton

  • 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

  • 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

  • 6 years ago

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

Prem Raja

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