With mortgage costs rising and high prices of houses making first-time buying difficult, many homeowners are earning extra cash by taking in a lodger. But life with a lodger may not be a simple as it seems.

According to a new survey from Zurich Insurance, a significant percentage of those who take in lodgers report both an emotional and financial toll.

By far the most common reasons for taking in a lodger were financial, with 20% unable to afford the mortgage payments by themselves. But a similar number of those who took in lodgers for financial reasons complained of late rent payments.

Nearly one of five (17%) of those surveyed said they suffered damage to their property. One in four (23%) say lodgers have been disrespectful towards their property and possessions.

The emotional expense of having a stranger in the house is also causing headaches for homeowners. Nearly two thirds (64%) believe their privacy is being invaded, with 40% feeling uncomfortable in their own home.

Three quarters of those questioned did not vet their lodger in any way before inviting them into their home.

Maria Donald, spokesperson for Zurich, says: "Property prices and the cost of living mean that many homeowners are feeling the pinch."

"Bringing a lodger in seems like the perfect way to earn a bit of extra cash if you’ve got a spare room, but as this research shows, it does need some careful thought and planning beforehand."

Zurich’s tips for picking a lodger:

• Set up interviews with prospective tenants and don’t be afraid to call them back for a second interview.
• Check with your mortgage lender that it is viable for you to take in a lodger.
• Tell your insurance company that you are going to take a lodger. Theft without forcible entry will be excluded from your policy.
• Lodgers’ possessions will not be covered on your home insurance policy. They will need to arrange their own insurance cover.
• Take up references.
• Have a written agreement that makes it clear what rent is due and when, any share of household bills, notice period and house rules.
• Request a month’s deposit in advance. This can be used to cover any unpaid bills.
• Keep your valuables out of site.