The UK's most affordable, high-quality decking board

4m Structural Composite 100x50mm Joist


About this product

Designed for external wall cladding or decking with reduced materials for a lighter construction, 4m Structural Joists offer a wide supporting surface for the base of your project.
Total Price: £40.00 Inc VAT
View our product installation guide

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4m Structural Composite 100x50mm Joist

4m Structural Composite 100x50mm Joist
4m Structural Composite 100x50mm Joist Everything you need to know about Cladco Composite Joists and Structural Composite Joists

Online Decking Calculator

Use our calculator to work out how many boards and fixings you need for your project.

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Start Your Project Properly with Our Structural Composite Joists

Making sure you begin your project in the right way is crucial, and our structural composite joists will do exactly that, enabling you to place your deck boards or cladding in the right way. Ideally placed onto a concrete base underneath, these structural composite decking joists will ensure that everything is correctly positioned and crucially give a strong foundation for your project.

Produced from recycled plastics and measuring 4000mm x 100mm x 50mm, the structural composite joists are available in charcoal colour only. The Colour of your Joists does not need to match the rest of your installation, as they will be installed within the foundations and can be hidden with Decking Boards and Fascia Boards.

Joist Length: 4m
Joist Width: 100mm
Joist Thickness: 50mm
Joist Weight: 17.24kg

Decking Joist Support You Can Trust

Used for elevated decked areas, you can also place structural composite joists directly onto grass if a solid concrete base isn’t an option. These are designed to ensure hard-wearing and long-lasting use for many years.

We recommend purchasing for every square metre of decking one structural composite joist and they should be spaced no more than 400mm apart at a maximum so that your base is as strong and reliable as possible. For more on how to install correctly, consult our installation guides.

Cladco Structural Joists require support every 1m for the structure of the joist itself. When installing composite decking onto structural joists we advise 400mm centres. For installations with PVC decking, we advise 300mm centres.

*Cladco Composite products are available as FSC® Certified for the same cost. If you require FSC® Certified products, please ask for these when placing your order.


Please click on the variable options on our checkout page.

Cladco offer a Nationwide delivery service (UK Mainland) We offer a range of options, please see the table below.

Useful Links: Delivery Policy | Collection Policy


Delivery is estimated 5 working days (1 week).


Collection from our Okehampton or Andover warehouse. Please note we need 2 hour notice.

Sample Packs

Sample packs are sent via Courier and delivered within 3-5 working days.

Pricing Table

National Delivery
(Orders under £1000)
Estimated 5 working days* £192.00
(Orders over £1000) Estimated 5 working days* £96.00
(Orders over £1500) Estimated 5 working days* FREE
Scotland Delivery Estimated 15 working days* £360.00
Parcelforce Standard
(Small Parcels)
3-5 Working Days £5.99
Parcelforce Standard
(Large Parcels)
3-5 working days £24.99
Sample Packs 5 Working Days FREE
*Please allow for public holidays and weekends (non-delivery days)

When your goods are delivered these are sometimes delivered on a pallet with the necessary associated packaging to ensure they arrive with you in the best possible condition. We view the pallet and packaging as necessary for the protection of the goods and therefore will be a part of what is delivered to you. It is your responsibility to dispose of these items in a responsible manner when appropriate.

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