Decking Joists

Timber, recycled plastic or composite joists?

Our sawn green timber joists provide a natural support system for decking boards, available in 4.2m and 4.8m lengths and in either 47x100mm or 47x150mm sizes. Timber joists can be protected with our deck tape to improve longevity and water resistance. Alternatively, choose our structural composite joists for ease-of-use with our fixing clips, providing a long-lasting decking frame.

Choose our 100% recycled plastic joists for peace of mind, extending the life of your decking frame with no maintenance required. As a recycled product manufactured from 100% post-consumer plastic, these joists do not absorb water and are suitable for installing directly onto the ground.

What size joists should I use?

Joists are available in different sizes depending on how your decking area will be used. Consider using wider Joists for more support underneath a busy decking area with lots of furniture. Choosing joist sizes with 100mm widths will be best suited for areas subjected to less weight, or fewer objects. If you are unsure about which size to choose, please call our friendly sales team on 01837 659901 for further advice.

How should I space my decking joists?

Decking Joists should be spaced throughout your decking subframe according to the type of decking board you are installing. This spacing is measured from the centre of one Joist to the centre of the next. For example, if you are installing our composite decking boards, joist centres should be 400mm, whereas for Nordeck decking boards, joists centres will be narrower at 300mm to provide adequate support for the wider boards.

How to install your decking joists

Decking joists can be installed using posts, joist hangers and subframe fixings. For further information about installing decking joists, please refer to our decking installation guides.

Protecting timber joists

Timber joists are sawn green treated using special preservatives to provide a long-lasting subframe. Additional protection from moisture damage, and standing water, can be created using deck tape over the top edge of the joists.