So you think you have done everything you can to maximise the return on your buy-to-let investment, from redecorating in cool, contemporary colours to installing new kitchen appliances. But the rent is just the bread and butter. Creative landlords can often identify extra ways of making money to put jam on it.
Moneymaking wheezes include renting out spare parking spaces, putting mobile phone masts on the roof, and selling wall space for advertising billboards.
Sites for billboards are in demand, and the poster advertising companies have surveyors looking for potential sites nationwide. But they always welcome enquiries from landlords, says Cliff Pratt, development director for Clear Channel.
"The things that make a site valuable are audience delivery and length of visibility," he explains. "A wall with passing glimpses from a B-road will be worth little, but a site visible for a long distance of a main A-road will be valuable."
The return varies from one or two thousand pounds a year for a 20ft hoarding somewhere in the countryside to over £100,000 a year for a piece of land with room for a high-technology lightbox on a major London approach, such as the Cromwell Road, Pratt says.
Billboard operators will do free surveys for landlords who think they have a suitable spot. If the survey is positive, the operator will do the rest. "We handle obtaining planning permission on behalf of the owner and thereafter we are responsible for finding advertisers, maintaining the site and paying insurance and business rates," Pratt says. Planning permission is almost impossible to obtain in purely residential areas, he says, so the best type of property for billboards is a shop with flats above, on a corner site, with a big blank wall on one side.
Some landlords gain extra income by allowing a mobile phone company to erect a mast on the property - but it's a controversial area. Demand for mast sites is soaring, partly due to increasing demand and also because the new 3G video phones need base stations closer together than those for current mobiles.
The best sites for mobile phone masts are the tops of high buildings or higher ground in the countryside, but the networks are also looking for side walls to mount antennas to fill in holes in coverage. If your mobile always cuts out behind your building, it might be worth investigating if your network has a problem in the area that you might be able to help with. In the countryside, mains power must be reasonably close by.
Planning permission will be needed for a mobile phone mast. In the town, it can help to disguise the antenna as an architectural feature (the flagpoles on many churches are, in fact, mobile phone masts), and in particularly sensitive country areas masts have been disguised as trees.
The income from a mobile phone mast varies, depending on the area and the type of installation - a big base station shared by all the networks will bring in much more than a small infill antenna.
The main drawback to a mobile phone installation is the controversy over possible health risks from the microwave radiation they emit. Living under them is unlikely to cause problems, but tenants may be deterred. It is probably not a good idea to offer the site if the property is next to a school. The new police mobile communication system, Tetra, seems to have provoked particular attention from protest groups.
The creative landlord can often find unexpected commercial opportunities at their property, says Ian Dickson, of Winkworth, in west London: "I passed a house in Twickenham the other day, on the way to the rugby, and they had given permission for a hot-dog stand in the front garden," he says. Even such occasional uses should be licensed but rarely are. The main danger in giving permission for retail activities in the front garden is that the neighbours will complain about the crowd, noise or smell.
Letting out the parking space that comes with your buy-to-let flat, leaving your tenant to find their own space, can cause problems. The secret is to buy a small flat in a development with lots of big flats and houses nearby. "Mostly, tenants in one-bed flats don't have cars but the owners of nearby million-pound houses will have more cars than parking spaces," says Dickson.
Corner houses often have gardens with direct frontages onto a road that may provide rentable parking spaces, but planning permission may be needed to allow access over the pavement.