Recycled Plastic Fencing and Posts: Where They Make Sense (and Where They Don't)

Short answer: solid recycled plastic posts and rails don't rot, so they're excellent in permanently wet ground, around livestock and in play areas where splinters matter. They're also heavier and noticeably more flexible than timber, they expand in heat, and they need shorter spans and good support. They're not the same thing as a PVC-U fence system, which is hollow, engineered profiles designed as a complete fence.

Three different "plastic" fences

People use "plastic fencing" for three quite different products:

1. Solid recycled plastic lumber. Posts, rails and boards made from mixed recycled plastics, used like timber. That's the subject of this article.
2. PVC-U fence systems. Hollow, UV-stabilised profiles designed as complete picket, privacy, pool and rail fences. This is what Simple Fencing sells.
3. Cheap plastic garden edging and mesh. Lightweight products for borders and temporary use, not boundaries.

Our existing article on plastic vs PVC fencing explains the terminology.

Where recycled plastic posts work well

• Wet ground, streams and boggy fields, where timber posts rot fastest at ground level
• Agriculture and equestrian: no rot, nothing for animals to chew, and manure doesn't affect it
• Play areas and schools: no splinters, nothing to treat
• Coastal sites: no rust or rot
• Raised beds and edging, where soil sits against the material permanently

Some manufacturers advertise design lives of 25 to 50 years or more for recycled plastic posts. Treat those as manufacturer claims rather than independently verified field results — long-term UK evidence varies by product and site. For context, the Wood Protection Association's default design life for UC4-treated timber posts is 15 years.

The limitations

Manufacturers' own installation guides are refreshingly frank:

• Flexibility. A recycled plastic fence is "far more flexible than the equivalent in wood," as one maker puts it. Taller fences need concrete or steel-reinforced posts.
• Spans. Guidance commonly limits post spacing to around 1–1.8m to avoid rails sagging, shorter than many timber fences.
• Heat expansion. Rails expand and twist in hot weather if fixed tight. Leave expansion gaps (one maker specifies about 20mm at rail ends), drill oversized holes and don't over-tighten screws.
• Weight. A 100 × 100mm × 2.5m post is a two-handed lift.
• Height. Some makers recommend a maximum fence height of around 1.8m, and concrete posts above that.
• Colour. Expect some mellowing in the first year or two.
• Price. Usually more than treated timber per post, though this varies a lot by grade.

Recycled plastic vs timber vs PVC-U

Combining materials

Recycled plastic often works best alongside other materials rather than on its own:

• Plastic posts with stock netting or wire, where the posts are the part timber would lose first
• Concrete or steel-cored strainers at corners and gates, with plastic intermediate posts
• Plastic gravel boards under timber panels, to keep the timber off wet ground
• Plastic posts and rails for a stream-side section of an otherwise timber paddock fence

Installation tips

• Set posts about a third into the ground, in concrete for taller fences.
• Keep spans short, or add intermediate supports.
• Leave expansion gaps at every rail end.
• Store materials flat, banded and shaded before fitting, because sun-heated loose rails can bend.
• Use stainless or galvanised fixings.

Sustainability

Recycled plastic lumber keeps mixed plastic waste out of landfill, a genuine plus. At the end of its life, recycling routes depend on the product and local facilities. Ask the manufacturer about take-back or recycling.

Our view

For a wet paddock, a stream-side boundary or a school garden, solid recycled plastic posts are well worth considering, often combined with timber or wire. For a decorative boundary, a pool barrier or a white picket front garden, a PVC-U system is designed for the job and stiffer per kilo. You can see our ranch fencing for paddocks and yards.

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