Foundation vent screen repair for raised Long Beach homes and their crawlspaces

It can be tempting to seal a vent with plywood, foam or a solid metal plate to keep animals out. That trades one problem for another. A raised crawlspace depends on cross ventilation to dry moisture coming up from the soil. When vents are blocked, humidity builds under the floor, and wet wood invites dry rot, dampwood termites, wood-boring beetles and mold on the subfloor and joists.

Heavy hardware cloth solves both needs. Quarter-inch mesh keeps out rats, mice, skunks, opossums and cats while leaving most of the vent open to air. We keep the opening clear of leaves, mulch and soil, and we advise against planting shrubs tight against vents or piling firewood in front of them. Where a vent sits below the soil line or a flower bed, a small retaining edge keeps dirt and sprinkler splash from burying it again.

Ordinary window screen and the thin wire used on many original vents are not strong enough. Rats chew through them and skunks push them in. Heavy-gauge galvanized hardware cloth is the standard choice and holds up for many years on most Long Beach homes, especially when it is set back from the face of the stucco and out of direct sprinkler spray.

For homes within a few blocks of the beach, the bay or the marina, stainless steel mesh is worth the extra cost. Salt air in Belmont Shore, Naples, the Peninsula and Alamitos Beach corrodes galvanized coatings faster, and we see original screens rusted to lace in those areas. Stainless lasts much longer in that air and keeps its strength. For either material, the fastening matters as much as the mesh. A screen tacked on with small staples can be pulled loose by a raccoon or pushed out by a skunk, so we use screws with washers, metal frames or overlapping edges.

• Quarter-inch mesh stops young rats and mice
• Heavy gauge resists chewing and pushing
• Stainless for homes near the beach and bay
• Overlapping edges and screw fastening, not light staples

Many homeowners replace vent screens and still find animals under the house because the access door was never addressed. On older homes, the door is often a piece of plywood or a small wood panel held by a single hook or a stick wedged against it. Over time it warps, rots at the bottom where it touches soil, or simply gets left open after a plumber or electrician visits.

We rebuild the frame where needed, fit a solid door with mesh at any ventilation opening, and add a latch that closes firmly but can still be opened for future inspections and termite work. A crawlspace that is easy for people to enter but hard for animals is the goal. We also look for gaps where pipes, gas lines and conduit pass through the stem wall, since those small holes are often how rats get in after the vents are fixed.

Long Beach has one of the largest collections of 1920s and 1930s raised-foundation homes in the region. California Heights has blocks of Spanish Colonial Revival homes with small stucco-set vents along the base. Bixby Knolls and Los Cerritos mix Spanish, Tudor and Craftsman styles, many with long perimeters and mature landscaping that hides vents from view. Belmont Heights and Rose Park are known for Craftsman bungalows with wood siding and rows of wooden-framed vents just above the soil.

These homes share the same weak points. Original screens are often eighty or more years old, sprinklers have been hitting them for decades, and generations of planting have pushed soil up against the vents. Skunks and opossums from the LA River corridor and nearby parks find them quickly, and roof rats that already live in the palms and fruit trees use them as a second way in. Homes in Bluff Park and Wrigley face the same issues, and close to the water the salt air speeds up rust on every screen.