Inspect for pests at the spring wall walk by probing timber at ground contact, looking for rodent holes, droppings, gnawing and termite mud tubes, and measuring every gap against the sizes pests can pass: 12 mm for rats and 6 mm for mice. Keep wood at least 15 cm off the ground on stone, because rot and termites destroy ground-contact wood in 2-5 years, and close entry gaps with mesh or sheet metal buried 30 cm along the foundation.
Part of Building Maintenance Schedules
Pest inspection is the regular search of a building’s base, timber and openings for the signs of termites and rodents, and the closing of the routes they use.
Pests Use Gaps And Damp, So The Inspection Looks For Both
The maintenance guide’s wall walk looks for rodent holes, and its summer work checks roof timbers from inside for insect damage: bore holes and sawdust piles. The shelter guide gives the first rule against termites and rot: always raise wood at least 15 cm above ground on stone, because wood touching the ground is destroyed within 2-5 years (Permanent Shelter). The rat-proofing guide gives the sizes: rats pass any opening larger than 12 mm and mice need only 6 mm; mesh of 12 mm stops rats and 6 mm stops rats and mice; a barrier of mesh is buried 30 cm below ground and extended 30 cm up the interior wall, bent outward in an L-shape because rats dig; and a 15 cm strip of sheet metal along the bottom of each door (Rat-Proofing).
Worked Example: Gauges And Mesh For One Building
Inputs: a building 10 m by 8 m; the rat-proofing guide’s barrier, 30 cm below ground plus 30 cm up the wall; doors 1 m wide.
- Perimeter: 2 × (10 + 8) = 36 m.
- Mesh width in the vertical part: 0.30 + 0.30 = 0.60 m. Area: 36 × 0.60 = 21.6 m², before any outward L-shaped return, whose width the guide does not state.
- Door strips: a 15 cm strip along a 1 m door, extending 3 cm past each edge (guide): 1.00 + 2 × 0.03 = 1.06 m long.
- Gauges: cut two sticks, 12 mm and 6 mm thick. A gap through which the 12 mm stick passes is open to rats, and the 6 mm stick to mice. The sticks cost nothing and turn “looks tight” into a test.
The same guide notes that a pair of rats can produce up to 1,500 descendants in a year and that rodents contaminate and destroy about ten times what they eat, so an unnoticed hole is expensive.
What You Need
- Two gauge sticks, 12 mm and 6 mm
- A probe or awl and a small hammer for tapping timber
- A lamp, for looking into voids
- Hardware cloth of 12 mm and 6 mm mesh, sheet metal strips and plaster
- Gloves and a damp cloth, for droppings
Method: Inspect And Close
Step 1: Look at the foot of every wall and every timber that touches or nears the ground, for mud tubes (narrow earthen tunnels running up stone or wall), sawdust-like droppings of insects, and holes.
Step 2: Tap and probe the timber. A hollow sound, or a probe that sinks in, means eaten or rotted wood.
Step 3: Measure every gap at doors, vents, eaves and pipe entries with the gauge sticks.
Step 4: Check droppings, gnawing and runs along walls and at the base of stores.
Step 5: Close gaps with mesh and sheet metal, fixing mesh with nails or staples every 3 cm round the edge (guide) and plastering over small holes.
Step 6: Remove the cause: woodpiles, grain spills and rubbish against the walls; raise or replace any ground-contact timber.
Step 7: Log what was found and closed. The corpus describes no termite treatment; the actions are to find the damage, remove the damaged timber and break its contact with the soil.
Common Mistakes
- Plastering over a hole rats can chew through. Use mesh or metal under the plaster.
- Mesh buried but not returned outward. Rats dig down beside it.
- Leaving ground-contact posts. Termites and rot are both quicker there.
- Poison as the only answer. It does not close the hole.
Safety
Droppings and damaged timber
Rodent droppings and nests can carry disease; do not sweep them dry, since that raises dust. Wet them with water or disinfectant, wear gloves, and ventilate the room. Timber eaten by termites can look sound outside and fail under a person: probe it before stepping on it or hanging weight from it (Roof Maintenance).
What’s Next
- Learn next: Systems & Tools — the tools for the rest of the building
- Combine with: Wall & Foundation Care — keeping the base dry and sound