Using Wood for Sea Defence

Groynes are a popular form of sea defence in the UK and many of our beautiful beaches have wooden groynes built on them. They play a vital part in efforts to help protect our beaches from further coastal erosion and to help our beaches be as stable of possible. They are also used in rivers to slow down the rate of erosion and improve navigation.  Although groynes can be made from several different materials, including stone and concrete, here we discuss why wood is a great option to choose.

How Groynes Work
The purpose of groynes is to stop the movement of sand or pebbles from moving too far along the coast due to a process called Long Shore Drift. The groynes are strategically placed at right angles along the coastline at varying points down the beach. They interrupt the water flow and capture the material, trapping it, which helps build up the beach and extend the land rather than it eroding away with the continuous tide. The difference groynes make to the UK coastline is extremely significant and are usually used in conjunction with other methods of sea defence, such as sea walls.

Groynes are often built from concrete or rocks. Although these are both effective options, wooden groynes are popular for their appearance compared to both of these. Over time, the wood endures battering from the waves which creates smooth looking wood that is a stunning feature on our coastline.

Compared to other hard engineering options, wooden groynes can provide good value for money. They can integrate into the environment more naturally than other forms of sea defence. Having a form of sea defence such as wooden groynes can provide peace of mind to both visiting tourists but also to residents and local business owners who live near the sea.

Simple to Construct
A great advantage of wooden groynes is that they are reasonably simple to construct, especially when compared to concrete. They are usually installed in groups and are easy to adapt depending on the state of the coastline. They can be built at different lengths and spaced apart easily to adapt to the beach they are placed on and how much sediment they want to capture.

Versatility in Size
You can have a completely solid groyne which will absorb all of the energy from the waves and therefore capture more sediment in that section of the beach. Alternatively, you can have partly open groynes which allow some water and sediment to pass through but still takes energy from the waves, but to a lesser degree.

Groynes need to be durable enough to withstand long exposure to the sun, marine life, salt water and the impact of the waves, and timber is a great material to cope with these factors. The lifespan of wooden groynes is decades and involves minimum maintenance.

Why is wood such a good choice?
We have been using timber for water construction for centuries. This is because wood has a lot of desirable qualities which are needed when building in water. These include

  • Having a high strength to weight ratio
  • It has high density
  • It is easy to work with
  • It has good durability
  • It has good resistance to abrasion

Marine timber has the ability to withstand strong winds and waves better than a lot of other materials. This natural resilience therefore makes it an obvious choice for both coastal and river situations. Wood can be cut to size and therefore is very versatile and adaptable to each individual project’s needs.

What types of wood are best?
Overall, hardwoods are a better option over softwood species as they can be more durable and have a higher resistance to abrasion.

Tropical hardwoods are great options to use. Two of the most popular choices are Ekki and Greenheart. However, other tropical hardwoods such as Balau and Jarrah have been used for water projects as well. Ekki is an especially great choice as it is also referred to as “iron wood” due to the strength of the material. It is because of its characteristics of being strong, durable and able to withstand abrasion that Ekki has been used in marine construction for over a century. 

Who are Eco Choice?
Eco Choice are specialist suppliers of certified timber and recycled plastic products. We were formed in 2005 with the aim of promoting FSC certified timbers to the UK construction industry. We offer products from a wide range of different timber species. We are passionate about supplying our clients with independently certified timber products while encouraging responsible and sustainable practices at the source level. To find out how we can help you and to get a quick, no obligation quote, please call us on 0345 638 1340, email us on or for more information about our sustainable timber products, please visit our website

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