Steel Wool vs. Copper Mesh for Sealing Mouse Holes
Both work for small gaps when packed tight and sealed in place. Steel wool is cheap and fine indoors. Copper mesh lasts longer outdoors and in damp spots.
Steel wool and copper mesh both work for plugging small rodent gaps, as long as they are packed tightly and held in place with a sealant. The CDC recommends steel wool for small holes, held in with caulk or spray foam. Copper mesh does the same job and holds up better outdoors and in damp places because it does not rust.
For larger holes, neither is the right tool. Use hardware cloth, sheet metal or cement. Here is how to choose and install each.
Steel wool
Steel wool is cheap and easy to find. Rodents do not like chewing through it. It works well for small gaps indoors, like around pipes under the sink, behind the stove or around a cable coming through a wall.
The drawback is rust. In damp spots, like crawl spaces, basements, outdoor wall penetrations and near AC condensate lines, steel wool rusts, stains and breaks down over time. Once it crumbles, the gap opens again.
Use a coarse grade, pack it in tightly so it fills the gap, and seal over it.
Copper mesh
Copper mesh is a knitted copper fabric sold in rolls for pest exclusion. It does not rust, so it lasts longer outside and in damp areas. It is easy to cut, roll and stuff into irregular gaps around pipes and lines.
It costs more than steel wool, but for exterior gaps, crawl-space penetrations and spots you do not want to revisit, it is usually worth it. Many pest control technicians use it as their default for small gaps.
Want a local rodent technician to look at it? Call to reach an independent provider serving Wichita. Same-day appointments are often available.
How to install either one
- Clean out loose debris from the gap
- Pack the mesh or wool in tightly, deep enough that it cannot be pulled out
- Seal over it with caulk or a small amount of foam to hold it in place and block air
- For exterior gaps, use an exterior-grade sealant
Foam or caulk alone is not enough. Rodents chew through them. The mesh or wool is what stops them, and the sealant keeps it in place.
When to use something stronger
Small gaps around pipes and wires are what mesh and wool are for. Larger openings need hard materials, as the CDC recommends:
- Hardware cloth for vents and larger openings, usually 1/4 inch mesh
- Sheet metal or flashing for chewed edges of doors, trim and siding
- Cement or mortar for holes in foundations and masonry
- Lath screen for openings in walls
Wichita homes with stone or brick foundations, torn crawl-space vent screens or gaps under settled slabs need these heavier fixes. See rodent exclusion.
Where copper mesh earns its cost in Wichita homes
A few spots around Wichita houses are damp or outdoors, where steel wool tends to rust out:
- Behind the AC unit, where the refrigerant line set and condensate line go through the wall
- Hose bibs and irrigation lines on the outside walls
- Pipe and wire holes in crawl spaces, which stay cool and sometimes damp after spring rains
- Gaps around gas meters and outdoor electrical lines
For brick homes, do not stuff weep holes with steel wool or copper mesh. Weep holes let water drain from behind the brick. Use weep vents made for that purpose.
Tools help too: gloves, scissors or tin snips, a putty knife or screwdriver to pack the mesh in, and a caulk gun with exterior sealant.
Do not block vents
Dryer, furnace and water heater vents must stay open to let air and combustion gases out. Do not stuff them with mesh or wool. Use rodent guards made for those vents, and keep the dryer vent flap working so it closes when the dryer is off.
If you are not sure what a pipe or vent is for, ask a professional before sealing it. The hole size article lists the common gaps to check.
Want a local rodent technician to look at it? Call to reach an independent provider serving Wichita. Same-day appointments are often available.
Questions Wichita readers ask
Can mice chew through steel wool?
Mice avoid chewing steel wool, but if it is loosely packed they can pull it out, and rusted wool breaks down over time. Pack it tightly and seal it in.
Is copper mesh better than steel wool?
For outdoor and damp spots, yes, because it does not rust. Indoors, steel wool works well and costs less.
Can I just use spray foam?
Not alone. Rodents chew through foam. Use it only to hold mesh or wool in place.
What should I use for bigger holes?
Hardware cloth, sheet metal, flashing, cement or mortar, depending on where the hole is.
Can I put copper mesh in my brick weep holes?
No. Weep holes let water drain from behind the brick. Use weep vents made to keep pests out while letting water through.
Sources
This page is general information, not legal or medical advice. Rules change, so check the linked sources for the current version.
Keep reading
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Rodents come back when the gaps stay open, food stays available or the source next door is untouched. Bait-only service is the most common culprit.
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