Boardwalks - Timber or Plastic

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What is it?

At Battleby's demonstration path, there are two boardwalks:

  • 1.4m wide sawn timber boardwalk with recycled plastic support posts.

timber boardwalk with plastic support posts battleby

  • 1.35m wide recycled plastic boardwalk with the beams (or stringers) resting on top of bearers. This boardwalk has no support posts driven into the ground.

plastic boardwalk battleby

How does it work?

The sawn timber boardwalk is made mostly from timber, but also includes recycled plastic posts which support the timber structure while being immersed in wet ground – these posts will not rot, unlike timber ones. This boardwalk consists of the following components:

  • Recycled plastic support posts.

  • Two timber cross bearers fixed to the plastic support posts.

  • One central timber stringer fixed to the cross bearers.

  • Two outer timber stringers fixed to the plastic support posts.

  • Timber deck bearers fixed to the inside face of the outer stringers.

  • Timber decking boards (with 10 mm gaps between each board) screwed onto the deck bearers.

  • Timber deck-level edge rails fixed onto the decking boards on either side.

  • Anti-slip flat sheets of glass reinforced plastic, impregnated with bauxite chips, are fixed on top of the decking boards to provide an anti-slip surface. Various companies can supply similar anti-slip material. At Battleby we have used SureGrip.

timber boardwalk supported with plastic posts battleby

The recycled plastic boardwalk is assembled very differently from the sawn timber one. This boardwalk consists of the following components:

  • Prefabricated plastic grooved decking board sections fixed to three longitudinal plastic beams that rest on plastic cross bearers on the ground.

  • Plastic cross bearers that lay flat on the ground under the plastic beams are not fixed to the ground in any way.

  • Plastic deck level edge rails fixed to the ends of the plastic decking boards.

This installation technique allows the boardwalk height to be adjusted simply by adding or removing cross bearers when the site's water table height rises and falls. The prefabricated decking board sections can be transported to site by helicopter or a low ground pressure vehicle such as a vehicle with rubber tracks.

plastic boardwalk supported on plastic bearers on ground battleby

Is it suitable?

The sawn timber boardwalk, with recycled plastic support posts, is ideal for wet environments such as wetlands and other situations where the timber decking needs to be raised above the ground. The recycled plastic boardwalk is more suitable for very wet sites and where there is a need to reduce visual impact in the landscape – it can lie directly on, or very close to, the wet ground. Both boardwalks provide a maximum useable deck width of 1.25m which is sufficient to accommodate one-way traffic by most users. They are also fitted with deck level edge rails making them accessible to wheelchairs and smaller mobility scooters.

How much will it cost?

Depending on the width, the length of the boardwalk to be installed, and other factors such as access for getting materials out onto site, a sawn timber boardwalk may cost £150.00/ linear metre, and a recycled plastic boardwalk may cost £250.00/ linear metre.

How do you install it?

For both boardwalk types at Battleby's demonstration path, materials were fabricated off site and transported onto site in kit form ready for installation. The method of construction was:

Sawn timber boardwalk

  • Stringers were laid out along the route, and then recycled plastic support posts and cross bearers were placed on the ground, roughly where the stringers were to join together.

  • Starting from one end, the positions for the plastic support posts were marked on the ground, and then the posts were driven into the ground to the required height. Two cross bearers were fixed to the two plastic support posts with coach bolts. The remaining plastic support posts and cross bearers were installed along the route in the same way.

timber boardwalk cross bearers attached to plastic posts battleby

  • Outer stringers were fixed to the inside face of the plastic support posts with galvanised steel joist hangers and brass screws. The central stringers were fixed to the cross bearers between the outer stringers with galvanised steel strip stirrups and brass screws.

timber boardwalk showing central and outer beams battleby

  • Deck bearers were secured to the inside face of the outer stringers with galvanised fencing wire ties.

  • Decking boards placed 10mm apart were screwed onto the deck bearers with self-driving screws.

  • Deck level edge rails were fixed to the decking boards on either side with self-driving screws.

timber boardwalk  decking boards and deck level edge rails battleby

  • Anti-slip flat sheets were fixed to the decking boards along the boardwalk with self-driving screws.

timber boardwalk non slip flat sheets fixed to decking battleby

Recycled plastic boardwalk

  • Prefabricated plastic grooved decking board sections and plastic cross bearers were laid out along the route, roughly where the plastic beam ends were to join together.

  • Starting from one end, the required numbers of plastic cross bearers were placed on the ground at the required distance apart to form two mounting points.

  • The first plastic decking board section was placed on top of the two mounting points.

  • At the required distance from the end of the first installed plastic decking board section, the required numbers of plastic cross bearers were placed on the ground to form the next mounting point.

  • The second plastic decking board section was placed on top of the second and third mounting points. The beam ends were joined together with the beam ends of the first installed plastic decking board section.

  • Plastic decking boards were fixed to three plastic beams with self-driving screws to cover the exposed joined beams.

  • Plastic deck level edging rails were fixed directly onto the ends of the decking boards on either side with self-driving screws.

  • This installation method was repeated along the route for the remaining plastic decking board sections.

Detailed drawings

If you like the look of the sawn timber boardwalk or recycled plastic boardwalk at Battleby as a potential boardwalk design for your project, download the detailed drawings below:

icon Sawn Timber Boardwalk - Elevation View & End View

icon High Density Recycled Plastic Boardwalk - Elevation View & End View

© 2014 Paths for All - Registered Scottish Charity No: SC025535, Company Limited by Guarantee No: 168554 inc. 19 Sept 1996 at Companies House, Edinburgh