The dilemma is chicken and egg. You think that the house you want oozes potential. But how can you ever know before you buy that you won't — literally — hit a brick wall when you begin any building work?

What are the red flags which could scupper your extension plans? The trick, say experts, is to do the detective work before doing the deal.

According to Jonathan Rolande, founder of property investment firm House Buy Fast, there are two types of extension: 'One stays within the footprint of the existing property, for example a loft extension. And the other builds outwards.

'Renovations may either fall under what's termed 'permitted development' (often the case with both garage and loft conversions) or those which will need planning permission from the local authority.'

That's why doing your homework (no pun intended) is vital. Researching the planning history of the property — through the local authority website — will flag up whether any prior planning applications have been granted. Or more significantly, refused — and if so, on what grounds.

Rachel Redwood, who works on the real estate team of law firm Kingsley Napley, explains: 'Different planning rules apply to properties in conservation areas as well as for listed properties, so a buyer should find out through their solicitor whether the property falls into either category.'

Some properties may also be subject to restricted covenants — third-party rights which are registered against the title of the property. These clauses can restrict alterations or extensions. They may even dictate what materials must be used.

A good clue as to whether your purchase will let you turn dreams into bricks and mortar is simply to look at the houses in the surrounding area.

Louise Kerridge, an account handler at Renovation Plan, which specialises in self-build insurance, says: 'If the property is part of a cluster of listed buildings, you may have restrictions on the style of extension and the materials you use, or you may not be able to build at all.'

Looking at similar-sized houses on the street will also offer clues as to what's feasible in terms of extensions.

Joe Warner, director of architecture at BDN Ltd, recommends investigating the materials used, too, by speaking to a structural engineer. For example, alterations to timber-framed properties can pose a challenge.

'Due to the nature of their design and engineering, timber alterations can be much more involved or restrictive compared with traditional masonry homes.'

Of course, not everyone wants the same thing, so it helps to think about the kind of extension you want. Bake Off fans may fantasise over a bigger kitchen, whereas those thinking of working from home might dream of a study.

So simply looking at the property — and the land it is built on — will give an idea of whether it can accommodate the project you have in mind. Put simply, is there enough space to build outwards?

'If you are making internal changes, the age of the property is important,' says Ian McConville, of builders' merchants MKM. 

'If it's an older property, you will have to go through brick to make room changes, if it's a new-build that's far easier.'

And one final thing to remember. While an extension should add value to your house, it's not automatically the case. 

So it's important to know your ceiling price: the maximum amount a buyer would pay for a property on your street before they can find a similar house for the same money in a better street.

'If you are at the ceiling price, it's unlikely any renovations or extension would add to the value, and you could end up out of pocket,' adds Ian McConville.