However, Neil Laird, the company's home insurance manager, warned that any structural changes could have an impact on the cost of cover premiums.
"As buildings insurance premiums are calculated based on the type of house, for example the number of bedrooms it has, creating extra rooms can have an impact on your premium even if you have unlimited cover," he explained.
Mr Laird added that homeowners should inform their insurer before starting work on such projects.
Recent research by Fairinvestment.co.uk found that a third of people in the UK do not have home insurance cover.
It was also found that women are more likely to have such cover in place than men.
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