It is very difficult for ordinary mortals to differentiate the harmless black ant from the carpenter ant. The distinction is paramount in the case of a prosecution for hidden vice. Indeed, only the presence of carpenter ants, among all insects, gives the right to a recourse in hidden vice against the former owner. However, case law has established that the mere presence of carpenter ants is not necessarily a hidden defect (Li c Boutilier, Court of Quebec, 2006). As emphasized Mario Naccarato"In spite of the hidden nature of the presence of carpenter ants (...) the only hidden character affecting a vice is not enough in itself to engage the responsibility of the seller".

How to recognize carpenter ants?

In fact, carpenter ants measure from 6 to 25 mm in length. These are the biggest ants found in Quebec. They are black with shades of red or brown. Contrary to the widespread idea that they eat wood (xylophages), they rather dig corridors and galleries, in affected wood and weakened by moisture, to install their nest. If we discover carpenter ants in winter or winged ants, then there is likely a colony inside the building (source: CAA Quebec).

Infiltrations of water or humidity

Having carpenter ants in a building "can therefore indicate a moisture problem or the decay of structures" (Health Canada). During nesting, they transform the wood into sawdust, which is a sign of their presence.

Normally, when a carpenter ant colony is discovered inside a building as well as damage to the structure, there are often problems of infiltration of water or moisture associated with it. Indeed, they look for places that are wet or affected by water infiltration. Thus, in properties with deficiencies that can cause problems of moisture and water infiltration, the probability of finding carpenter ants is higher than in healthy homes.

Sources of problems

We must look for sources of moisture and / or water infiltration and solve these problems simultaneously with the extermination of the ants. The sources can be:

  • French drain not functional;
  • Presence of cracks in foundation walls
  • Defective sealing at the junction between the footing and the foundation walls;
  • Defective sealing at the junction between the exterior cladding and the foundation walls;
  • Defective sealing around doors and windows;
  • Sealing joints deficient or absent in the building envelope;
  • Lack of adequate clearance between the exterior cladding and the floor;
  • Lack of adequate clearance between the junction of the foundation walls and the ground;
  • Slope of land that directs the water towards the house;
  • Lack of adequate clearance between the basement window sill and the exterior floor;
  • Gutter descents pouring near the foundation walls;
  • Installed terraces whose platform level is higher than the junction of the base of the exterior cladding;
  • Absence of chantepleures at the base of the masonry facings;
  • Absence of a waterproofing membrane at the base of the exterior doors at the ground floor level;
  • Acrylic exterior cladding closed at the base;
  • Condensation due to improperly installed thermal insulation or insulation with low thermal resistance;
  • Impaired air tightness that will cause condensation inside and then high humidity in building materials.

Exterior carrying walls

The elements of wood structure that are most frequently damaged by carpenter ants are the external load-bearing walls, in particular, the lower parts of the walls that are in contact with the moisture of the exterior soil or the concrete of the foundation walls.

Often in houses - where the ground floor is lower than the exterior floor level - it can be seen that bed rails and rim joists are more susceptible to carpenter ant infestation.

We also find this kind of infestation in components such as:

  • Wooden structure, around doors and windows that are not watertight;
  • Under the patio doors leading to the outdoor terraces;
  • Thermal insulation accessible from the outside as insulation from the base of a cantilevered window.

These wood elements, which can be softened by moisture and water infiltration, are the ideal environment to house carpenter ants, which can easily dig into and settle in moist woods and search for available food. the House.

Carpenter ants and hidden vice

Carpenter ants in insulation