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Extreme C4 Decking Screws 5x56 mm

16.99 (incl. VAT) (0.08/pc)
Article no: 40-9559-1
  • Decking screws for outdoor use in demanding environments.
  • Recommended for hardwoods such as larch.
  • Sharp tip and threads which helps prevent splitting.
  • Corrosion class C4.
  • Type-approved by SITAC (Swedish Institute for Technical Approval in Construction).
Stock status
Web stocks In stock
Availability in store
Select store
  • Select store
  • Reading, Broad Street
Type approved decking screw that is ideal for working in tough environments and pressure-treated timber.

The screw is partially threaded which means that the decking board is clamped securely against the underlying joist. The shank also has a double helix to help remove debris form the hole and improve clamping even under low loads. The slash point tip of the screw cuts through the fibres of the wood efficiently for improved driving and less likelihood of splitting when the screw is inserted close to the edge of the timber. The ribs underneath the head of the screw help when countersinking into timber for a smooth finish with no protrusions.

This decking screw is made of steel treated with an anti-corrosion coating giving it a corrosion class of C4 and is type-approved by SITAC (Swedish Institute for Technical Approval in Construction). The screw is much harder than a regular stainless steel screw and is recommended for use with hardwoods such as oak, ash and larch. Quick-drive screw with a high corrosion resistance making it ideal for exterior use on constructions which are exposed to corrosive environments or in direct contact with the ground such as jetty posts, concrete moulds and uncovered decking.

The screw head has a T25 recess to provide a good drive with minimal risk of camming out.

Product Specifications

Number in pack 200 pc
Type of screwdriver bit T25 
Screwdriver bit included No 
Head Countersunk 
Corrosion protection class C4 
Stainless steel Yes 
For outdoor use Yes 
Length 56 mm
Diameter 5 mm
Packaging size 13 x 9.5 x 7.2 cm
Packaging weight 917  g

Shopping info, delivery & returns

At Clas Ohlson you can always shop securely and quickly. You will always have an open return policy up to 90 days. Your order will usually be dispatched within 2-3 days. Exception to this is the busy season such as Christmas.

Usual questions about returns

Clas Ohlson offers 2 year

Except where we state otherwise, we provide a two year guarantee on our products to cover materials and manufacturing defects and other defects that affect the product?s normal functioning under the guarantee period. This excludes consumable products, such as lightbulbs and batteries, which by their nature cannot be returned in a new or unused condition. For further information on other such consumable products excluded from the guarantee, please contact our customer service department on 0845 300 9799.

Read more in our terms and conditions of purchase

Clas Ohlson offers 2 year

Money back

Are you not happy with your purchase or have you changed your mind? Don't worry, at Clas Ohlson you will always have an open return of 90 days. To get your money back you must:

  • Show the receipt.
  • Return the product within 90 days.
  • Return the product and accessories in the same condition as they were when you bought them.

Read more about returns in our terms and conditions of purchase