Open navigation

Iroko Smooth Decking 21 x 138mm

Price From: (exc VAT) £13.32 (inc VAT) £15.98
(exc VAT) (inc VAT)
Price per linear metre £7.40 £8.88
Price per square metre £51.74 £62.09

5-7 day delivery service available

Delivery options and pricing calculated at cart


Scroll to view more information on this product


This product is temporarily out of stock.
It is due to come back in stock imminently.
For more information call 0151 495 3111.


Iroko is an extremely popular hardwood, especially in high-end domestic locations. Its highly versatile nature allows it to also be used as cladding and slatted screens. Colours range from a light yellow-brown to a deeper golden-brown, but tend to darken slightly over time, providing a rich and evocative colour tone.

At a glance

  • Extremely Durable
  • Kiln Dried at source
  • Interlocked grain
  • Yellow-brown to golden brown in colour
  • Ideal for commercial and residential use
  • Silva Recommended Finish - Sansin Dec
    Iroko looks best finished in the following colour tone...

Interlocking grain and evocative colour tones

Iroko(Chlorophora excelsa) is native to the west coast of Africa. It is tough, dense and very durable (660kg/m3 on the Janka Hardness scale). It is frequently used in decking, cladding and slatted screens where durability is a requirement thanks to Iroko’s highly versatile nature.

Silva Timber's Iroko is kiln dried at source, providing a consistent moisture content and immediate installation with no acclimatisation necessary. 


First and Second (FAS) - the highest grade of Iroko available 


Iroko is an attractive alternative to Teak. It resembles Teak in grain patterns and colour after ageing.  The grain is interlocking and the texture is medium to coarse with open pores. It is a light yellow-brown colour when freshly cut, but quickly turns to a darker golden-brown with age. 


Iroko is highly durable. It is also known to be very naturally resistant to decay. 


Iroko has a very high density with 660 kg/m3. This is ideal for use in decking and cladding. 


Iroko dries rapidly. Once dry, it is generally easy to work with.


Iroko has excellent strength properties, similar to Teak.

Storage and Handling 

For best results store your Iroko decking out of direct sunlight and do not expose it to weather before installation.  Keep the boards off the ground by stacking them flat on timbers placed on the ground; this allows air to circulate around the stack.  Cover your deck boards with a waterproof breathable sheet to protect them from sun and rain until you are ready to install them.

Read more

Finishing & Protection

It is recommended that a finish is applied to all surfaces, including ends, before installation. The type of coating will be determined by the final finish and appearance desired.

Why Pre-finish?

  • Enhances the natural beauty of wood
  • Ensures a consistent finish
  • Applied in factory conditions
  • Long lasting protection against weathering
  • Simple maintenance routine
  • Reduces onsite labour costs

The importance of sanding

As Iroko is an incredibly dense species it is essential to sand the deck boards prior to applying the finish. Sanding opens up the cells on the surface to allow the stain to properly penetrate. This facilitates deeper penetration of the stain for a consistent appearance and longer service life.

What is weathering?

There is a risk involved when leaving wood exposed to the elements. During the weathering process wood can appear unsightly as the material can blacken due to moisture getting into the fibres and pulling out tannins and extractives. Finish protects the wood from moisture absorption and UV degradation.

Installation & Advice

Deck Board Spans

21 x 145mm Iroko decking should be installed with joists spaced at 400mm centres.  When installing the boards diagonally the joists should be spaced at 300mm centres.

Deck Board Spacing

21 x 145mm Iroko decking should be installed with a 5mm gap between the boards.  The space between the boards allows for air circulation and slight expansion with changes to the humidity level.


It is important to allow adequate air circulation underneath the deck to prevent cupping and warping of the boards.  It is recommended that a vapour barrier is used on the ground to prevent moisture from absorbing into the underside of the deck boards.


There are a number of different options available for fastening deck boards to the joists.  We recommend screwing through the face of every board using 5.0 x 60mm Countersunk Stainless Steel Screws. Fix two screws into every joist at quarter points on the deck board (36mm from each edge).  We recommend that pilot holes are drilled prior to inserting the screws.  This is particularly important at the ends of the boards to prevent splitting. 5.0 x 60mm Countersunk Stainless Steel Screws will flex slightly as the wood expands and contracts as the level of humidity changes with the changing of the seasons.

For a cleaner finish we suggest recessing the screws and using plugs to hide the screw heads.  Plugs can be cut from off-cuts of decking using a relatively inexpensive drill attachment called a plug cutter. 

Hidden Fasteners

There are a number of hidden fastening systems available.  None of these products are as reliable as screwing through the face, and it is likely that there will be some additional movement of the deck boards when using hidden fasteners.  If using a hidden fastening system it is essential to allow adequate ventilation beneath the deck and to coat the deck boards with an appropriate finish on all sides prior to installation.

Hardwood wrench

The longer the deck board the greater the tendency for it to be slightly bowed. To overcome this, most professional deck installers will carry a tool called a Hardwood Wrench, or Bow wrench, which enables the user to easily straighten a bowed board single handed as it is installed.  The Bow wrench is relatively inexpensive and can save a lot of time, so it’s worth buying even if you only use it for one project.  It can also he hired from some tool hire stores.

End Sealer

Iroko decking from Silva Timber is end-sealed during the manufacturing process to help prevent splitting and checking on the ends of boards.  We recommend that if the boards are cut during installation then the exposed end grain should be sealed as soon as possible.   A clear, water-resistant wax such as Osmo Wax End Sealer should be used.

Cleaning and Maintenance 

Your Iroko deck will benefit from regular cleaning.  Brush the deck with a stiff broom to remove dirt and dead leaves, and ensure that the gaps between the boards are clear of organic debris.  Clean the deck periodically with Multi Wash by Sansin® to remove grime and mildew.  Iroko decking can be pressure washed, but it is important to select a low setting to prevent the wood fibres on the surface from being damaged.

If your Iroko deck is weathered it is possible to restore the natural colour with Wood Cleaner by Sansin®.  This product will remove weathering, mould, algae, mildew and iron stains and prepares the surface for recoating. 

If an existing finish or stain has broken down it can be removed using Paint and Stain Remover by Sansin®.  This product will remove most failed oil-based or latex finishes, extreme weathering, water stains, mould and mildew and restore wood to its natural colour.


Iroko decking can be crosscut with good quality chop saw using a tungsten carbide tipped blade.  Ripping can be done on a standard table saw, using a good quality, well-aligned fence and a tungsten carbide tipped blade.  When drilling, always use the highest quality drill bits available. If screwing through the face, use a countersink bit with a positive stop to ensure that all the screw heads end up at a consistent depth.  Screws can be lubricated to make installation easier.

Routing or planing can be done with either high speed tungsten carbide cutters. The feed speed should be fairly slow. 


A dust mask and eye protection should always be worn when working with any wood.  Avoid the inhalation of wood dust.  We recommend a dust mask with an activated carbon filter. Some people may have an allergic reaction to hardwood dust.  Remove wood splinters immediately to prevent infection.


To ensure its quality, Iroko decking from Silva is carefully manufactured, graded and inspected at source.  It is inspected again during the order picking process prior to despatch.  However, Iroko decking is a natural wood product and is subject to variations in weight, density, colour, grain and performance. Iroko decking is subject to dimensional changes as the moisture content in the wood fluctuates with humidity in the air. Swelling, shrinkage, checking, and other movement of individual pieces are normal occurrences in wood decking.


First and Second (FAS) - the highest grade of Iroko available 

  • FSC
  • PEFC
  • Trada member
  • Responsible purchaser
  • Cedar Shake & Shingle Bureau
  • nbs plus
  • Secured by