Garden Room Base Detailing – Including Sub-Base Protection

For screw pile foundations: the barrier is deployed after piles are set and before the bearer frame arrives. The mesh is threaded around each pile position as it is unrolled across the footprint. At each pile, a small slit or fold in the mesh allows it to pass around the pile shaft. Laps at joins: minimum 100mm. Perimeter edge: folded up against the pile cap level and secured to the outer pile or perimeter frame.

For concrete pad foundations: the barrier is deployed around and between pad positions. At each pad, the mesh is cut to fit around the pad perimeter, with cuts kept as small as possible to minimise exposed edge length. Joins between cuts are overlapped by 100mm. The perimeter edge is folded up and secured.

For adjustable pad systems: the barrier is deployed before the pads are locked at final height. If the pads are on a continuous paved surface, the barrier may be laid on top of the paving between pad positions. If on bare ground, the mesh is deployed at ground level as normal.

The perimeter junction — where the sub-base barrier meets the outer structure — is the highest-risk detail in the installation. It is where the mesh is most likely to lift, where the edge is most accessible to rodents, and where any gap in coverage will be most immediately exploited.

The correct perimeter detail requires the mesh to be folded upward at 90° against the outer bearer or perimeter frame and secured at intervals of no more than 300mm. The fold should extend upward by 50–100mm. This eliminates the gap at the structure edge and prevents rodents from pushing beneath the mesh edge.

Where perimeter skirting is to be installed for aesthetic reasons, the skirting is fixed over the folded mesh edge — not as a substitute for it. The mesh edge provides the exclusion; the skirting provides the visual finish.

The sub-base barrier is one of several elements in the floor structure specification. The complete base detail from ground upward is: ground preparation — sub-base barrier (BaseShield™) — bearer frame — floor joists — insulation — vapour control — floor deck. The barrier is a ground-level component and does not interact with the elements above it.

This means the floor structure above the barrier can be specified independently — any insulation type, any vapour control layer, any floor deck material. The barrier specification is fixed regardless of what is specified above it.