An opening that is genuinely in use looks different from one that is merely open, and the difference is visible from a Cambridge lawn with a phone camera.
What gives it away is not the hole. It is the marking around it.
What a rub mark is
An animal using the same opening several times a day makes contact with the same few square inches of material every time. Fur carries oils, dust and dirt, and repeated contact transfers them — which over weeks produces a darkened, faintly polished patch immediately around and below the entry.
On white uPVC soffit or fascia it reads as a grey or brownish smudge with soft edges. On painted timber it looks like the paint has been worn thin and dirtied. On brick or mortar it is subtler — a darker patch that does not match the weathering either side.
How to tell it from ordinary dirt
- It is localised. General weathering runs along a whole elevation; a rub mark is a patch a few inches across
- It has a direction. Usually smeared downwards and outwards from the opening, following the way the animal comes and goes
- It is in the wrong place for rain. Weather staining runs from above, from a gutter joint or a drip line
- It is asymmetric. Heavier on one side, where the animal turns
- The material looks worn as well as dirty
Compare it with the same point on the other side of the roof. Nearly every house has a matching detail on the opposite gable or the other end of the eaves. Two identical details where one is marked and one is clean is about as clear an answer as this subject offers.
The other physical traces
- Gnawing at the edge. Fresh work looks pale where the weathered surface has gone, with coarse tool-like marks rather than a clean break
- Material displaced. A tile sitting proud, an end cap missing, a soffit board pushed out of line
- Fibres. Insulation strands caught at the edge of the opening, carried out on the way through
- Hairs caught on a rough edge
- Debris below. Fragments on the ground, a windowsill or a lower roof directly under the point
How to look
From the ground, in daylight, with the camera at full zoom, standing at each corner in turn and sighting along the roof line rather than at it. Early or late sun rakes across a surface and makes both staining and any distortion obvious, where midday light flattens everything.
Photograph anything that looks marked and note which elevation it is on. That single fact — which side of the house — is the most useful thing you can supply when you call.
Do not go up to look. Every one of these marks is legible at twenty times zoom from the lawn, and a ladder at the eaves is the genuinely dangerous part of this subject.
Questions
How long does a rub mark take to appear?
A few weeks of regular use. A very fresh entry may show gnawing without much staining yet.
Do old marks stay after they have gone?
Yes, for a long time. Marking alone does not prove current activity — it needs to be read alongside the noise.
Can rats leave the same marks?
They leave darker, greasier smears, usually at low level rather than at roof height. Location is the tell.
Squirrel Control Cambridge
Squirrel control in Cambridge 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 Cambridge, call 01502 630 122, or read the Cambridge squirrel control page.