Sealing the gaps rats and mice use to enter San Francisco buildings, so control work holds after the traps come out.
Fastest: call (855) 974-4733. Or send this and we call you back.
Rodent exclusion is the sealing of every gap that lets rats and mice into a building. UC IPM advises closing openings larger than 1/4 inch with steel wool, wire screen or sheet metal. In San Francisco's older buildings, a technician finds the openings, seals them and checks that nothing is left inside. San Francisco Pest Control connects San Francisco County callers with an independent local company.
Trapping removes the rodents that are in the building. Exclusion decides whether more arrive. It is the part of rodent work that lasts, and it is also the part that depends most on the building. A newer house with tight construction may have a handful of openings, while a Victorian flat, built when plumbing, gas and electricity were added to a wooden frame over many decades, may have dozens. Roughly 45 percent of San Francisco homes were built in 1939 or earlier, according to census-based figures reported by housing sites and the SF Chronicle, and every renovation since has cut a few more holes.
The standard from UC IPM is simple: seal openings over 1/4 inch with steel wool, wire screen or sheet metal. Those materials work because rodents gnaw through caulk, foam and plastic but not through metal. San Francisco Pest Control is a call line, answered 24/7, that connects you with an independent local pest-control company. A same-day visit is offered only when a technician is free, and no arrival time is promised.
Do not seal an opening while you suspect an animal is still inside, and do not climb onto a roof or lean from a ladder to patch a gap yourself. A trapped animal can die in the wall, and a fall is a far greater risk than a rodent.
Say where droppings, noises or damage appear. A same-day visit is offered only when a technician is free, and no arrival time is promised.
The technician walks the foundation line, garage and entry doors, vents, utility lines, the roof edge and any branch, vine or wire touching the building, marking each opening that is larger than 1/4 inch.
Under sinks, behind appliances, around the water heater, in laundry closets and at the attic access, the technician looks for gaps around pipes and wires and for gnaw marks that show a route.
You receive a list of the openings, the material proposed for each and the price, confirmed before work starts. You can choose to close all of them or begin with the most used routes.
Sealing too early can shut rodents inside. Trapping goes first, and the final openings are closed only when catches have stopped and no fresh droppings are seen.
Gaps are closed with metal or screen that rodents cannot chew, held in place and finished neatly. The technician checks the work and tells you what to watch for, such as a door sweep that wears or a vine that grows back.
No San Francisco price for rodent exclusion from a named publisher was confirmed, so none is printed here. Sealing is priced by the work involved, and these factors move a quote.
| Job | Typical range | What it includes |
|---|---|---|
| Number of openings | Varies with the building | A few gaps under sinks and a vent are small, while a full-perimeter sealing job is larger |
| Size and type of openings | Varies | Small gaps take steel wool, while larger ones need screen, sheet metal or carpentry |
| Height and access | Depends on access | Rooflines, steep walls and tight crawl spaces add time and equipment |
| Materials | Per material used | Metal and screen cost more than sealant alone, and a larger repair needs more |
| Repairs to the structure | Quoted separately | Rotted or broken wood around an opening may need a carpenter before it can be sealed |
Your exact price is confirmed on site before any work starts. The San Francisco pest control cost guide explains how quotes are built.
Trapping removes the rodents that are inside, but the openings stay. If the gaps are not closed, more rodents arrive from outside, often within weeks. Sealing is what turns a one-off removal into a lasting fix, which is why it is the final stage of most rodent jobs.
A common pattern is a building that has been trapped several times with the same result. Each round clears the animals present, and each time the food and the entry points bring more.
Rodents also tend to repeat the same route. A mouse that found a gap under a sink may leave a trail that other mice follow. Closing the gap breaks the trail, not just the animal count.
Steel wool, wire screen and sheet metal work because rodents cannot chew through them, as UC IPM advises. Caulk, expanding foam, wood filler and plastic mesh alone do not hold up, because rodents gnaw through them. Metal packed into a gap and held with sealant is the usual approach.
Expanding foam is the most common mistake. It looks solid and fills the hole, but a rodent chews through it in a night. Foam can be used to hold metal in place, but never alone.
For a large opening, such as a rotted vent corner, the fix is metal flashing or screen screwed to sound wood. If the wood is damaged, the first step is repairing it, which may be work for a carpenter and not a pest technician.
The most common routes are gaps around pipes and wires where they pass through walls and floors, worn door sweeps, damaged vents, cracks at the foundation and openings at the roofline. Older buildings have more of these because pipes and wires were added over time.
Under a kitchen or bathroom sink, the hole around a drain is often far bigger than the pipe. In a laundry closet, the same is true around supply lines and dryer vents. These holes are hidden by the cabinet or the appliance, so they are easy to miss.
Outside, the places to check are utility lines, weep vents at the base of a stucco wall, the corners of garage doors and the roof edge. Roof rats, which climb, will use a gap near the roofline, while Norway rats and mice are more likely to enter at ground level.
Sealing keeps out anything that fits through the gap, but this site does not trap, remove or relocate wildlife. For raccoons, skunks and similar animals, a technician can discuss structural sealing only, once the animal has left. Wildlife handling is governed by state rules, not the pest license.
The page on wildlife proofing explains the sealing-only approach. It does not involve capturing or moving animals.
If an animal is in the building, do not seal it in. Wait until it has gone, and contact the proper wildlife authority for advice on removal.
Coarse steel wool packed into a gap around a pipe, held in with sealant, works for holes up to a couple of inches across. Rodents cannot chew through it. It is quick and cheap, and it is the standard first fix under sinks and in utility closets.
Metal screen covers larger openings such as vents, weep holes and foundation openings. It lets air through while blocking rodents. It needs to be fixed firmly at the edges, because rodents will pull at a loose corner.
Used for larger holes, damaged corners and the bottom of a door or access panel. Metal is durable and can be shaped to the opening. It is the usual choice at the roofline and where a gap meets a damaged board.
A worn sweep under a garage or exterior door is a common entry for mice. Replacing it with a tight, durable one closes the gap and usually helps with drafts too.
San Francisco's older housing is the central fact. With about 45 percent of homes dating from 1939 or earlier and the median home built in 1948, there are many buildings where rooms were added, pipes were rerouted and chimneys were closed off, each leaving a gap. Victorian and Edwardian rooflines add eaves, cornices and decorative trim that can hide openings.
Many older facades in the city are protected, so exterior changes may need care. Sealing is mostly done with small amounts of metal and sealant that do not change how a building looks, but if a repair would alter the front of the building, mention it early.
With dry summers and wet winters, gaps that look harmless in August may let in water and animals in January. Checking the roofline and foundation at the end of summer, before the rain arrives, is a sensible time to schedule sealing, though a rodent sign at any time of year is a reason to call.
Call any hour and explain what is going on. You get a clear price before any work starts.
Not sure if you're covered? Check your ZIP code.
Rat control in San Francisco: telling Norway rats from roof rats, finding how they get in and closing the route.
Mouse control for San Francisco buildings: where house mice get in, how they are trapped and how the gaps are closed.
Cleanup and repair in attics and crawl spaces after rats or mice: droppings, nesting, insulation and the routes in.
We could not source a San Francisco or Bay Area pest control price, so this guide prints no dollar figure.
The San Francisco Department of Public Health names Norway rats, roof rats and house mice as the important urban rodents.
In California, wildlife such as raccoons, skunks and coyotes falls under the Department of Fish and Wildlife, not the structural pest control licence.
It depends on the county and sometimes the city.
UC IPM advises sealing any opening over 1/4 inch, which is about the width of a pencil. Mice can pass through very small gaps, so a technician checks for anything near that size.
Mostly, but materials wear. Door sweeps fray, vents loosen and trees grow back to the roof. A short check each year, particularly before the wet months, helps keep the work effective.
Small jobs under a sink can be done with steel wool and sealant. Roofline work, high walls and crawl spaces are safer left to a technician. Do not seal anything until you are sure no animals are inside.
Not normally. The materials are small and fixed in place. If a historic or protected facade is involved, say so when you call, and the technician will plan around it.
It depends on the number and size of the openings and on access. A technician gives an expectation on the visit, but no finish time is promised on the call.
No. Cleanup is separate. If an attic or crawl space has been fouled, see the page on attic and crawl space rodent work.
Not by itself if rats are inside. Trapping comes first, then sealing. Read about rat control for how the two fit together.