Rodent Barrier Under Decking: Specification, Materials & Installation

Raised decking creates one of the most accessible harbourage sites for rodents in domestic gardens. Unlike garden rooms or modular buildings, decking often has multiple open edges and wider ground clearances — giving rats and mice easy access from several directions. For the full picture on why this problem is so commonly missed, see our guide to preventing rodent access beneath raised structures.

A sub-base barrier installed beneath the decking before or during construction is the most effective way to prevent rodent nesting and damage.

The ideal barrier for decking should be a flat, roll-out mesh that covers the full footprint. It must have a mesh opening small enough to exclude mice (under 8mm), be resistant to gnawing, and durable in permanent ground contact.

It should also allow water drainage and airflow — critical for maintaining the timber substructure and preventing moisture-related decay.

BaseShield™ SubBase Defence meets all of these requirements. It is manufactured from welded wire mesh with a 7.66mm opening and 0.80mm wire diameter, hot-dip galvanised after welding for long-term ground-contact durability.

Each roll covers 25m² (1m × 25m), making it practical for decking projects of any size. The roll format is faster to install than cut-to-size panels, with fewer joints and no specialist tools required.

Before installing the deck frame, clear the ground of debris and vegetation. Roll out BaseShield across the full footprint, overlapping rolls by at least 100mm. Secure the barrier edges to the perimeter frame or use ground pegs.

Then build the deck frame and boarding on top. The barrier sits at ground level beneath the entire structure, preventing access from every direction.

For full step-by-step instructions, see our installation guide.