Exclusion

Wildlife Exclusion for Older New York Homes: Sealing Entry Points in 1940s–1980s Construction

May 30, 2025·12 min read

The vast majority of wildlife intrusion calls Wildlife NY receives come from homeowners in homes built between the 1940s and 1980s — the post-war housing boom that produced Nassau County's Levittown subdivisions, Westchester County's colonials and Cape Cods, and the attached rowhouses and brownstones of Brooklyn and the Bronx. These homes are between 40 and 80 years old, and the original wood-based exterior assemblies have had decades to deteriorate in ways that create dozens of potential wildlife entry points. Understanding the specific vulnerabilities of New York's older housing stock — and how to permanently seal them — is the foundation of effective, long-term wildlife exclusion.

Why Older New York Homes Are Vulnerable

Post-war construction in New York followed relatively standardized patterns. Homes were built primarily of wood-framed exterior walls, wood fascia and soffit boards, and wood trim at the roofline. These materials were adequate when new, but repeated thermal cycling, moisture exposure, paint failure, and the simple passage of time cause wood to crack, shrink, rot, and pull away from adjacent materials — creating gaps that did not exist at original construction.

Compounding this, many older New York homes received cosmetic updates in the 1970s, 1980s, and 1990s — aluminum or vinyl soffits and fascia installed over the original wood — that actually created new wildlife entry pathways. When aluminum replacement soffits are installed over original wood soffits, a gap typically remains between the two layers. This gap, connecting directly to the attic space, is an ideal bat, squirrel, and starling entry point that is invisible from the exterior until animals are already inside.

Ridge ventilation was also handled differently in older New York construction. Many homes built before 1970 lack modern ridge vents entirely, relying on gable vents — which, when their screens deteriorate, become open pathways for bats, flying squirrels, and birds. Homes that did receive ridge vents as retrofits often got aluminum cap-style vents without integrated insect or pest screening.

Decade-by-Decade Vulnerabilities in New York's Housing Stock

1940s and 1950s Construction (Levittown Era)

The mass-produced Cape Cods and ranch homes of Nassau County's post-war suburbs were built quickly and economically. Original construction features that now create wildlife vulnerabilities include:

• Open-eave construction with unfilled gaps between rafters at the eave line — original screening was minimal and has long since deteriorated.
• Gable vents with original wood louvers and stapled screening — the screening is typically completely absent on 70-year-old homes.
• Chimney crowns of this era were rarely properly tooled or waterproofed and have deteriorated significantly, leaving open mortar joints and gaps at the flue liner that bats exploit.
• Original wood fascia that is now 70 to 80 years old and has experienced significant shrinkage, leaving gaps at joints and at the rafter tail-to-fascia connection.

1960s Construction

Split-levels and larger colonials of the early 1960s introduced more complex rooflines with dormers, valleys, and multiple roof-to-wall junctions. These geometric complexities create additional potential entry points:

• Dormer sidewall-to-main-roof junctions where step flashing has failed or is missing.
• Valley flashing joints on intersecting roof planes that have deteriorated under ice and water exposure.
• Attached garage roof-to-house junctions that create a complex void space accessible from both the garage attic and the main house attic.

1970s Construction

Homes built in the 1970s saw the widespread adoption of aluminum and vinyl exterior products — often as original installation rather than retrofit. The junctions between these materials and adjacent wood substrates, now 50 years old, are a primary source of wildlife entry points:

• Aluminum J-channel at the eave line, where it meets the fascia board, develops gaps as the aluminum expands and contracts over decades of thermal cycling.
• Vinyl soffit panels that have lost their retaining clips and sagged, creating openings at the soffit-to-fascia junction.
• Original wood window trim that has not been maintained behind vinyl siding — the wood has rotted and created voids at the window-to-wall junction.

1980s Construction

The 1980s produced larger homes with more complex architectural features — eyebrow dormers, bay windows, and multiple roof levels — along with the widespread adoption of pre-engineered roof trusses. Truss-framed attics create large open spaces with uniform temperatures, making them more attractive to wildlife. The complex exterior geometry of 1980s homes multiplies the number of potential entry points, and 40-year-old caulk at every window, door, and penetration has long since failed.

Materials for Permanent Wildlife Exclusion in Older New York Homes

Effective wildlife exclusion in older New York homes requires materials matched to the specific entry point type and the wildlife species involved:

• 16-gauge galvanized hardware cloth (1/2-inch mesh): The workhorse material for wildlife exclusion. Used for gable vent screening, roof vent covering, chimney skirts, and fascia gap repairs. Heavy enough to resist squirrel and raccoon gnawing, and the 1/2-inch mesh excludes all common New York wildlife except bats (which require 1/4-inch mesh or purpose-built bat exclusion screens).
• Copper mesh (Stuf-fit or equivalent): Used for irregular gaps, pipe penetrations, and spaces where rigid hardware cloth cannot conform to the opening. Copper resists corrosion and is not chewed by rodents, unlike steel wool which corrodes rapidly and loses its sealing integrity.
• Galvanized sheet metal flashing: For repairing and closing larger structural gaps at fascia, soffits, and roof-to-wall junctions. Custom-bent sheet metal provides durable, weather-resistant closure.
• Polyurethane caulk (paintable): For sealing hairline cracks in wood, gaps around pipe penetrations through exterior walls, and small openings at trim joints. Silicone caulk is acceptable but less paintable and does not adhere as well to weathered wood.
• Chimney caps with mesh skirts: A stainless steel chimney cap with a surrounding mesh skirt is the definitive solution for chimney-related bat, raccoon, and bird entry in older New York homes. Both the flue opening and the surrounding crown area must be addressed.

The Exclusion Inspection Process

A proper wildlife exclusion inspection of an older New York home is a systematic exterior survey conducted at multiple heights:

1. Ground-level survey: Foundation, crawl space vents, utility penetrations (gas, electric, HVAC), and gaps at the foundation-to-sill plate junction are assessed from the ground.
2. Mid-height survey: Window and door frames, gaps at siding transitions, and utility penetrations through exterior walls are inspected from a ladder.
3. Roofline survey: Fascia, soffits, gable vents, ridge vents, chimney, roof penetrations, and all roof-to-wall junctions are inspected from the roof or from an extended ladder at the eave line.
4. Attic interior assessment: Confirms the species present, identifies the interior access points, and assesses the extent of any contamination or structural damage.

For a free wildlife exclusion inspection of your older Nassau County, Westchester County, or Rockland County home, call Wildlife NY at (516) 447-4673. We inspect the full exterior, identify every entry point, and provide a written exclusion plan with material specifications and pricing.

Frequently Asked Questions