The residential boom and scarcity of land, especially in our cities and towns, means that the plot your house stands on could be worth far more than the value of your house. Following a recent spate of joint house sales around the capital, vendors are realising that a little community spirit can go a long way to boosting the bank balance.

Joint sales all over the city from Cabinteely to Killeen Road and Finglas are a sign that ordinary house owners are looking further than their back wall when thinking of selling, and trebling the value of their property through a 'neighbourcate' or co-operative sale.

Several such sales have recently come to the market in Dublin, putting a new spin on the term neighbourhood watch and giving neighbours a lot more to talk about. The new 'neighbourcate' trend, which sees neighbours clubbing together to sell entire streets and cul-de-sacs of houses, gives home owners the chance to cut a larger slice from the property pie and benefit from soaring land prices.

Take the residents of Meakstown Cottages in Finglas, who are set to earn a 36m windfall thanks to a joint sale. The owners of 18 cottages and one bungalow have managed to increase the value of their property from 500,000 to 2m.

According to Karl Mulligan, ReMax, the selling agent at Meakstown, "There is a scarcity of land around the city and going forward, rather than developing greenfield sites, developers are looking to increase density on existing sites, so co-operative selling is set to increase."

However group selling is not all smooth sailing. Meakstown has sparked some concerns and a note of warning from Fingal County Council, which last week announced that while the residents are entitled to sell property to whoever they choose, developers should be aware that the site has rural cluster zoning which restricts planning to smallscale development to serve local needs.

Despite concerns, however, the trend is gathering pace.

One recent successful sale, agreed by Remax, at Killeen Road, Dublin 10, will see six vendors achieve in excess of 1.5m each for properties on a 1.45 acre site. Mulligan also currently has three similar projects on his books and is negotiating a further four projects.

Lisney also has a joint sale project currently under consideration in Sunnyhill Park, Cabinteely. Situated off the N11, in an area with a precedent for high density, the five vendors are likely to achieve the asking price of 30m for the bungalows.

So far, estate agents have been leading the way, helping neighbours to negotiate these tricky waters. But how can you tell if you're sitting on a goldmine, and what if you want to take matters into your own hands?

According to Tara Cosgrove, Property Locators, land with significant development potential is currently going through the roof and people with the small house/lots of land combination are likely to be very successful selling their property this way.

"Areas where planners are allowing high density or where there are currently high-rise developments, say a sevenstorey building, would be particularly attractive to developers."

But Cosgrove warns that those looking to do it for themselves would be wise to get expert professional advice.

"For starters, once you've decided to go ahead, it would be very important to ensure you have a legally enforceable agreement as to how the proceeds of the sale will be divided up."

But that's not the only reason vendors would be best advised to consult the experts.

Valuing the individual properties in a joint sale requires an experienced eye, according to Peter Kenny, associate director of Colliers Jackson-Stops, which is currently looking after the joint sale of Riversdale House in Rathgar for 10.3m.

"On a practical level, owners have to make an assessment as to the values of their individual property. Assuming that every house in the estate would have identical values would be wrong.

"Take Riversdale. This involves the sale of two very unequal properties where the percentage would be very difficult to work out. As a result, we are running the two sales in tandem."

Kenny advises vendors interested in pursuing a joint sale to look at what's going on around them and assess the potential of the area in terms of development.

"You really need to know the market and who to target.

It wouldn't necessarily always be the case that a high-rise apartment should be developed on the site. Sometimes the margins are better with good quality single units.

Assessing development potential is a very specialised area.

Locations where we might see this take off in the near future include Dublin 4, Dublin 6 and around Killiney, where land prices are high, according to Kenny.

But Mulligan believes that all areas around the city could potentially net their owner significant sums. "There aren't necessarily good or bad areas.

It's more about densities and premiums achievable in a growth market."

"We're getting more and more enquiries about this and I think we'll see a lot more of it in the future, " says Kenny.

"Houses with large gardens in older developments or mature residential areas will have far greater value if they are sold jointly rather than individually." Although if your property is listed and can't be demolished, 'neighbourcate' selling is not for you.

The key to success with this sort of venture is agreeing your objective, advises Kenny.

"You have to agree on what you are doing as a group; after that it's all about paperwork and marketing."

So far Mulligan has completed sales without any problems, but goodwill and sticking to the agreement in principal are absolutely necessary.

But while 'development potential' spells big bucks for house owners, it could also spell tax trouble. Cosgrove points out that selling a property with development potential also exposes vendors to captial gains tax. "If someone buys a group of houses and pays people way over the odds, the amount way over the odds would not be tax-free."