Dec 092012
 

4.406.1 Rodent proofing. Annular spaces around pipes, electric cables, conduits, or other openings in plates at exterior walls shall be protected against the passage of rodents by closing such openings with cement mortar, concrete masonry or similar method acceptable to the enforcing agency.

 

COMMENTARY

 

Purpose:

This section requires barriers in exterior openings to prevent rodents from entering the dwelling and causing health hazards and/or damage to a building’s components and systems. It addresses the sealing of openings for controlling rodent intrusion, which differs from California Energy Code provisions intended to prevent air leakage.

 

Examples of Acceptable Methods of Implementation and/or Compliance:

Openings should be sealed or closed with materials that cannot be damaged or penetrated by rodents:

 

•      Cement mortar.

•      Concrete masonry.

•      Lightweight concrete/cellular concrete.

•      Similar methods withstanding rodent penetration and approved by the enforcing agency.

 

Background:

The California Energy Code requires joints and other openings in the building envelope, which are potential sources of air leakage, to be sealed to limit infiltration and exfiltration. CALGreen specifically addresses protection of structures from rodent entry, disease and damage. The perceived reference to California Energy Code provisions has been deleted from CALGreen due to redundancy.

 

Rodents can cause significant damage to a building’s structure or operating systems by gnawing on wood, plastic, copper, electrical conduits or other components. They may also damage stored items or personal property. Rats can burrow under building slabs undermining a foundation. A rodent also may nest in insulation and contribute to salmonellosis (food poisoning) and carry

other diseases.

 

Therefore, penetrations, voids, joints and openings in structures need to be sealed to prevent passage of rodents. Openings include, but are not limited to, cuts, holes, and notches in bottom plates, exterior wall openings around plumbing pipes, flues, exhaust vents, and HVAC conduits. Openings as small as ¼ inch can be used by a rodent to enter a wall, crawl space or attic. In addition, doors, windows, or screens should fit tightly. Other openings such as chimneys and vents should be rodentproof without compromising their function. Dense vegetation, especially around roofs, walls and foundations, should be avoided to decrease rodent habitat and access into or onto buildings.

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