And certainly there are some tremendous bargains to be had. If you're prepared to take a few risks, you have the potential to get your hands on a pretty impressive property below market value.

Yes it might need some work doing, but your chances of making a profit are higher. If you're serious about building a property investment portfolio, it's pretty much the only way to do it.

But a serious warning has been issued about a potential problem when you find property in this way ? to do with planning permission.

Property experts Auction Finances says some buyers are being caught out when buying unusual homes, because they can't get official permission to do the renovations.

As the popularity of buying at auction increases, it's happening more and more.

The problem especially affects people who find property that isn't currently in residential use, such as an old church hall, a school house, windmill or barn.

They can be picked up relatively inexpensively at auction, especially if they are in disrepair and will need a significant amount of cash pumped in to make them good enough for a family to live in.

The company says the safest thing to do when you find property is figure out the planning status of a site before bidding for it.

This can be done by contacting the local council, who are responsible for planning matters.

If a property does have permission for works to be done, the seller is likely to get more money for it, as it represents less of a risk to the buyer.

Incredibly, the size of the UK's self-design and build property market is a massive ?3.8 billion. The company says TV programmes like Grand Designs which show how developers find property and turn it into their dream home is driving growth.

Certainly, we have noticed that buying in this way seems to be gaining in popularity.

Last week the BBC Two show The Truth About Property approached us to get help finding case studies for its new series.

Among the people it was looking for were an investor who picks up properties at auction, and a first time buyer who intends to get on the property ladder and find property in this way.

If you have already bought a property without the relevant permission, the company has a set of suggestions to help you turn your empty building into a home more quickly.

First of all it suggests you get professional advice from a planning consultant. This may seem like an unnecessary expense, but as an expert in their field they will know the subtle differences between getting an application through and having it refused.

If you think your application is going to be refused then withdraw it and resubmit it once an expert has advised you. This is a sensible way to avoid black marks against your development.

You should also talk to your local planning officer. Many of them are glad to offer informal advice. This is in their best interests ? the more that a scheme complies with planning regulations and advice, the easier it is for officers to make solid recommendations to the planning committee of the council that actually permits building changes.

Finally, just as you were when you were trying to find property in the first place, be flexible. If you can show compromise in your plans, you are much more likely to get the kind of home you've always dreamed of.