A home insurance firm has advised customers that they could lose out if they do not tell their insurer about building works on their property.

The warning comes after the organisation unveiled research stating that 13% of homeowners were thinking of making structural changes to their house over the next year.

Whilst the number of homeowners planning structural changes to their property is down 40% from 2008 due to the recession, around 30% do not realise they need to let their insurer know.

The most popular choice of work that people planned to get on their home were Loft conversions.

These were also the most widely planned structural change in 2008 (1.3 million); however the second and third most popular changes last year were building a conservatory (1.2 million) and adding a rear extension (950,000).

The new research reveals that the average amount to be spent per household on structural changes over the next year is £22,730.

Big spenders looking to deck out their homes

Of those planning works, one in three (34%) intends to spend more than £20,000, just 5% plan to spend over £50,000 and 3% expect their works to cost more than £100,000.

As a result, home insurers have warned that homeowners planning to make any structural changes to their property should inform their buildings insurer first in order to ensure that they are fully protected for the increased value of their home through expanding and improving it.

Joanne Mallon, from the firm, said how building extra rooms on a property is an option but said people should be sure to check how it affects their policy.

Ms Mallon said: "In the current housing climate, creating extra space in your home is another option for those who have maybe decided to put their plans to move on hold. Buildings insurance premiums are calculated based on a number of factors, such as the type of house or the number of bedrooms it has, so creating extra rooms can have an impact on your premium even if you have unlimited cover.

"Homeowners should know that in the event of an incident happening during or after the works are completed they could be left underinsured or even invalidate their insurance entirely if they have not informed their insurer first."

Recession DIY

For those who want an extension, but need to save money, cutting corners is a way to penny pinch. As a result, many will turn to their DIY skills to improve their homes.

However, insurers have warned that property owners could be at risk of invalidating their insurance policies should anything go wrong.

With the average cost of a claim for DIY related damage being £600, DIY enthusiasts should consider checking their home insurance policies to ensure that it covers them for accidental damage in case the job goes terribly erroneous.

Shockingly, 16% of people have damaged their home while attempting to make improvements.

Ottokar Rosenberger, Sales and Marketing Director from an insurance firm said: "Clearly some DIY tasks are easier than others but, in one momentary slip of concentration, every job has the potential to go wrong.

"Indeed, accidental damage of sinks, baths, ceramic hobs or glass in doors is included in most policies, but common DIY disasters like drilling into a water pipe or putting a foot through the ceiling might not be covered and can be expensive to rectify."