The latest ten-year data from ongoing full-scale utility pole trials at two UK field test sites confirms the effectiveness of dual-layer composite ground-line barrier sleeves in preventing ground-line decay.

The independent report, produced by the Building Research Establishment (BRE), evaluated the long-term performance of ACQ preservative-treated wooden utility poles installed both with and without dual-layer composite ground-line barrier sleeves (Polesaver Rot-Guard™). Performance was assessed by measuring pole moisture content and the presence of decay over time.

Real-World UK Field Conditions

The trials were specifically designed to replicate typical UK installation environments:

Peterborough – Poles installed in tarmac, representing built-up urban settings

Penistone – Poles installed in open-field conditions with wet ground, grass cover, and tree shading that limited drying

Clear Performance Differences After 10 Years

After a decade of in-ground exposure, ground-line decay was identified in un-sleeved poles at both test sites, confirming that decay-causing conditions were present.

In contrast, all poles fitted with barrier sleeves remained sound and free of decay.

Across both sites, poles protected with barrier sleeves recorded average moisture content levels 20% lower than un-sleeved poles. This reduction confirms the sleeves’ effectiveness in limiting moisture ingress at the critical ground-line zone, significantly lowering decay risk.

Visual inspection further reinforced these findings. Standard preservative-treated poles showed clear signs of wetting and algae growth at the ground-line, while sleeved poles remained visibly dry and free from algae above the sleeved section.

Reinforcing Long-Established Durability Principles

The findings support a long-recognised principle in wood pole durability: controlling moisture and isolating wood from decay-causing conditions is essential to extending service life.

While preservative treatments provide a strong baseline level of protection, the data demonstrates that adding a composite barrier sleeve significantly enhances performance by isolating the pole from soil, moisture, and wood-decaying organisms.

Composite ground-line barrier sleeves form a physical, impermeable barrier between the pole surface and surrounding soil. In doing so, they not only prevent the ingress of moisture and decay organisms but also retain preservative within the protected zone, reducing loss through leaching over time.

“This trial clearly shows that isolating the critical ground-line section of a pole from the causes of wood decay delivers significant long-term performance benefits.
These results reflect the same proven outcomes seen across numerous other tests, including sustained pole strength over time. Supported by more than 30 years of volume use worldwide, composite ground-line barrier sleeves offer network operators a level of protection they can rely on with confidence.” said Simon McArt, Global Sales Manager for Polesaver.

Implications for Utilities and Network Operators

For utilities and distribution network operators under increasing pressure to extend asset life, reduce unplanned interventions, and control whole-life costs, the evidence from this rare, long-term in-ground field trial provides a level of confidence that goes beyond laboratory testing or short-term studies.

The results strengthen the case for specifying ground-line barrier sleeves as standard, supporting improved whole-life performance, reduced maintenance intervals, and greater long-term resilience of wooden pole infrastructure.

Visit Polesaver.com for more information.

For additional context or to request a copy of the report visit: https://polesaver.com/blog/10-year-field-test/