Both animals gnaw, both damage insulation and both are a reason to act. What they do is not the same, though, and the differences are worth knowing — not least because the damage itself is evidence.
Gnawing
Squirrels gnaw coarsely and excavate: wide paired grooves, material removed in quantity, a shallow scooped hollow with splintered edges. It is incisor wear rather than purpose, so it happens anywhere convenient at height. Rats gnaw more finely and more purposefully, working at one point to open a route, leaving a defined hole with cleaner edges and fine dust below it.
Cable
Both are a fire risk and both need an electrician. Squirrel damage tends to be a stripped section — sheathing removed along a length, cores exposed. Rat damage is more often a bite through at a point. Squirrels do more of it in a loft simply because that is where they are and where the cable is.
Insulation
- Squirrels excavate a large open bowl and shred material for lining. The disturbance is dramatic and localised, with compressed tracks radiating from it
- Rats shred material finely and build flatter, more compressed nests in confined spaces. The disturbance is less dramatic and more widespread, and heavily soiled over time
Contamination
This is the clearest difference and it favours nobody. Rats urinate more or less continuously as they move, so an established population saturates the material it lives in — which is why an infested loft smells strongly of ammonia and why the contamination is widespread rather than localised. Squirrels do not mark in that way, so contamination is concentrated around nesting and resting places and a loft with squirrels in it usually smells of very little.
The building fabric
- Squirrels damage the roof itself on the way in — lifted tiles, torn felt, gnawed soffit, verge and eaves detail. That damage admits water, which is where the expensive consequences start
- Rats more often damage the inside of the structure — boxing, boards, pipe insulation, service runs — and their entry damage is at ground level or in drains rather than on the roof
The damage tells you where to look. Damage concentrated at the roof edge, admitting weather, is a squirrel story. Damage inside the structure with a sound roof edge is not.
Which is worse
They are worse in different ways, and it is not a useful competition. Squirrels do more damage to the fabric of the roof and more damage per animal; rats bring heavier contamination, larger numbers and a population that grows in place. Both are worth dealing with promptly, and both put cable at risk, which is the part that matters most in either case.
Questions
Which does more damage?
Squirrels do more to the roof fabric per animal; rats bring heavier contamination and larger numbers. Both put cable at risk.
Can I tell from the damage alone?
Often, yes — the pattern of gnawing and where the entry damage is are both informative. It works best alongside the timing of the noise.
Does rat damage smell more?
Considerably. A strong ammonia smell from a roof space is a rodent finding rather than a squirrel one.
Squirrel Control Haverhill
Squirrel control in Haverhill is £280 fixed cost. Proofing work, where it is needed afterwards, is £180. Call 01502 630 122 and tell us what you have heard or seen.
For squirrel control in Haverhill, call 01502 630 122, or read the Haverhill squirrel control page.