Damage to chimneys and flue liners for gas fires may not be visible above the roofline.
A New Zealand roofer has warned homeowners to be wary of damage to chimneys under the roofline of their home.
Speaking to the New Zealand Herald, Christchurch roofer Tony Stuart suggested that such appliances should be treated as dangerous until they can be inspected.
He told the newspaper: "In many chimneys, the mortar holding the bricks together is just sand and cement but over the years it has lost its capacity to hold the bricks together.
"The bricks are just stacked on top of each other."
Speaking to the Weston Forum earlier this week, chimney sweep Dave Burns explained that homeowners need to ensure they use a quality tradesperson of repute to inspect their chimney.
He suggested that if an offer appears too good to be true from a chimney sweep, it probably is, claiming that many repairs he has to carry out are the result of mistakes made by others in the first place.