Is Chicken Wire Adequate for Sub-Base Rodent Exclusion?
No. Chicken wire is not an adequate product for rodent exclusion under raised structures. This is a consistent finding across pest management practice, structural construction, and basic product specification analysis. The reasons are straightforward — and understanding them helps clarify exactly what the correct product looks like.
Why chicken wire fails: the aperture problem
Chicken wire (hexagonal mesh) has a nominal aperture typically quoted as 12mm, 19mm, or 25mm. Even the smallest standard specification — 12mm — is too large to reliably exclude mice. House mice can compress through gaps of 6–7mm. A 12mm hexagonal aperture is almost twice the critical dimension.
The hexagonal geometry also creates a range of effective aperture sizes across the mesh surface. The flat sides of the hexagon represent one dimension; the diagonal across the opening represents another, larger dimension. A mouse testing the mesh will find the largest available opening, which in a standard hexagonal mesh may be 15–18mm even in a product nominally rated at 12mm.
Additionally, the hexagonal woven construction is not dimensionally stable. Under compression — the load from a structure being built over the mesh — the apertures distort further. Woven wire junctions have no fixed geometry; they flex and slip. Within weeks of installation under a deck or garden room, a chicken wire barrier has apertures that bear little resemblance to its nominal specification.
Why chicken wire fails: the gnawing problem
Standard chicken wire is manufactured from light gauge wire — typically 0.5mm to 0.7mm. This gauge is below the minimum 0.80mm required for reliable resistance to rat gnawing. A rat with access to a chicken wire barrier will begin gnawing at the wire junctions — the weakest points in the mesh — and can create a rat-sized opening within a short period.
The twisted wire junctions in chicken wire are particularly susceptible. Each junction is formed by wrapping one wire around another — creating a single-wire contact point that has no additional material to resist gnawing. Compare this to a welded wire mesh, where each junction is two wire strands fused together, presenting twice the material thickness to a gnawing rodent.
Why chicken wire fails: the corrosion problem
Chicken wire intended for garden use is typically galvanised before the wire is formed into hexagonal mesh — a pre-galvanised product. The galvanising process applied to the finished wire protects the wire strands, but every twisted junction has bare metal at the contact point — the zinc layer is worn away by the forming process.
In ground contact, those junction points corrode first. In a typical UK garden environment, a pre-galvanised chicken wire product in permanent ground contact will show significant junction corrosion within three to five years. As the junctions corrode, the mesh loses structural integrity — apertures enlarge further and the product becomes ineffective as a physical barrier.
What to specify instead
The correct product for sub-base rodent exclusion is a hot-dip galvanised welded wire mesh with a clear mesh opening no greater than 8mm and a wire diameter of at least 0.80mm. Each element of this specification addresses one of the chicken wire failure modes: the small, consistent aperture excludes mice; the wire diameter resists gnawing; the welded construction maintains aperture geometry under load; and the hot-dip post-weld galvanising protects every surface including weld points.
This specification is what BaseShield™ SubBase Defence is manufactured to. It is not a generic product adapted to this use — it is purpose-designed for ground-contact sub-base protection in raised structure applications.
The right product for this application
BaseShield™ SubBase Defence is the alternative to chicken wire for sub-base protection: welded construction, 7.66mm clear mesh opening, 0.80mm wire diameter, hot-dip galvanised after welding. Every specification criterion that chicken wire fails, BaseShield meets.
BaseShield™ SubBase Defence
Forti NovaA purpose-built rolled sub-base barrier system designed specifically to prevent rodent access beneath raised structures. Supplied in 1m × 25m rolls — covering 25m² per roll — with a 7.66mm clear mesh opening and hot-dip galvanised finish applied after welding.
Roll size
1m × 25m
Coverage
25m² per roll
Mesh opening
7.66mm
Construction
Welded wire
Finish
Hot-dip galvanised
Wire diameter
0.80mm
Installation
Unlike chicken wire, BaseShield maintains its aperture geometry under the load of a structure built above it. Install flat, overlap joins by 100mm, fold the perimeter edge upward, and secure before the floor frame is set.
Read the full installation guideFrequently Asked Questions
Stop access beneath your structure
BaseShield™ SubBase Defence is installed during construction to provide permanent sub-base protection. Designed for garden rooms, modular buildings, decking and screw pile foundations.