Open fireplace – crumbling chimney mortar

Causes

Deterioration due to age

Moisture ingress into the bricks

Listed under: masonry, brick, heating, Services, chimneys and flues and fireplaces, mortar

Cause

Deterioration due to age

Repair

  • open fires are an extremely inefficient form of heating – much of the heat goes up the chimney rather than into the room. If the fireplace has been used for heating a room, consider switching to a more efficient option such as a heat pump. Low-income homeowners can get a Government grant for up to 80% of the cost (up to $3000 incl GST) of an approved heat pump or wood/pellet burner for the main living area
  • older chimneys that are no longer structurally sound are dangerous, particularly in an earthquake. (Pre-1930s buildings commonly used a weaker type of mortar.) Engaging a chartered professional engineer to assess and advise on options to restrain, strengthen, demolish or rebuild the chimney is recommended
  • if a decision is made to take down the chimney, this does not require a building consent. This exemption is limited to any building up to 3 storeys high as long as the removal does not affect the primary structure, any specified system or any fire separation (which includes firewalls protecting other property). Remember to check roof sarking/framing which is sometimes supported on chimney structures
  • any repair work that is necessary after chimney removal – for example, making good the gaps left in a roof – can also be done without a consent. The work must not leave the house in a worse position (in terms of thermal performance, durability etc.) than before the work was done
  • you should only attempt these repairs yourself if you have the skills, knowledge, experience and tools to complete the job properly. Poor quality work on the building exterior can result in leaks and other problems and may affect your house insurance cover

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Cause

Moisture ingress into the bricks

Repair

  • if the fireplace and the chimney are structurally sound and damage is only to the edges of the mortar, and you want to keep the structure as is, scrape out loose mortar and repoint with new mortar
  • if the fireplace and chimney may not be structurally sound, see the first repair above

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