Rats In The Loft

What's happening?

Noise in a loft after dark is usually rats or squirrels, and the two sound different: rats scratch, scurry and gnaw more or less continuously through the night, while squirrels are noisy in daylight and heavier. Brown rats climb far better than people expect, and typically get into a roof space by running a downpipe or a cable, through a gap where a soil vent pipe passes the eaves, or up through a cavity from a defective drain. Once in, they gnaw — insulation, timber, water pipes and electrical cable — and a rat-damaged cable is a genuine fire risk. Rats also breed fast, so a couple of nights of noise is not a small problem that will pass. This is one of the few household pests where UK law puts a duty on you.

What usually causes it?

• A defective or disused drain giving rats a route from the sewer up into the cavity and roof
• Gaps at the eaves, verge, soffit joint or where a soil vent pipe passes the roofline
• Climbing a downpipe, cable run, trellis or overhanging branch to reach the roof
• Missing or damaged roof tiles, or an open ridge end after storm damage
• Food available nearby — bird feeders, chicken feed, compost, pet food, bin bags left out
• Dense ivy, decking or a woodpile against the wall giving cover right up to the building
• A neighbouring problem, an empty property or a nearby building site displacing an existing population

When should you call a pest controller?

Call a pest controller promptly — rats breed continuously and a loft population grows fast. Call urgently if you can smell burning, if lights or sockets have started behaving oddly, or if you find gnawed cable, and get an electrician to check the wiring afterwards regardless. You should also report the problem to your local council: the Prevention of Damage by Pests Act 1949 places a duty on occupiers to notify the authority where rats are present in substantial numbers, and gives councils powers to require treatment on land they do not own.

What will the pest controller actually do?

• Survey the loft, eaves, cavity and drainage to establish the entry route rather than only the activity
• Identify the species from droppings, gnaw marks, runs and smear marks before choosing a method
• Deploy traps or professional-use rodenticide in tamper-resistant boxes, following the stewardship rules for the site
• Proof the entry points — eaves, verges, service penetrations, air bricks — so the population cannot re-establish
• Check drains and recommend a drainage survey where a defective drain is the likely route
• Remove carcasses and contaminated nesting material, and advise on insulation and cable damage needing a trade

Your legal position, and the council's

Rats are the one common household pest where the law puts an obligation on the occupier rather than leaving it to choice. The Prevention of Damage by Pests Act 1949 requires occupiers to notify the local authority where rats or mice are present on their land in substantial numbers, and gives the authority power to serve notice requiring steps to be taken — including on a neighbouring owner whose land is the source.

That cuts both ways and is worth knowing when the problem is not yours. If rats are coming from an empty property next door, an untended garden, a commercial bin store or a defective public sewer, the council's environmental health team has powers you do not, and a written report starts that process.

• Report substantial rat or mouse activity to your local authority's environmental health team
• Keep dated notes and photographs of droppings, damage and the source if it is outside your property
• A defective drain is a common route and a repair, not a pest treatment — ask for a drainage survey
• An accumulation or deposit that is prejudicial to health can be a statutory nuisance under the Environmental Protection Act 1990