Red Mantle Chimney Methodology

Heritage home with 3 replacement heritage replica chimneys by Red Mantle

                                   Safe        Strong      Stunning     and      Lightweight        

- Red Mantle (RM) replica chimneys are a patented system that utilises a composite construction and real brick veneers to achieve stunning and authentic results.

- A great way to describe the RM system would be to think of building a fibreglass yacht mast and cladding it with brick tiles - we then connect this structure to the roof of your home.

- This chimney methodology works incredibly well, it is light, strong, will not rot or rust and is weather-tight.

- The structure and all connections to your home are fully engineered and compliant.

- Our chimneys come as a convenient prefabricated unit and usually take one day to install. We make replacing chimneys easy!

- Red Mantle chimneys look 100% authentic.


A look under the bonnet as to how we fabricate these lovely structures:


Support Frame:


  1. The chimney support frame and all connections to the building are fully engineered to NZ building code requirements and consider wind and earthquake loading.
  2. Producer statements (PS1, PS3, PS4) and a memorandum of design (MOD) are supplied along with sketches for the builder and details on all the connections.
  3. Construction monitoring (CM4) oversight will be undertaken.


Frame build and install

  1. Frames are constructed in either timber or steel…builders often prefer timber.
  2. The frame is manufactured either in the Red Mantle factory or onsite. This is then installed and connected to the building as per the engineering specification and NZS:3604 (building code guide).
  3. Once installed the frame (above roof) is then flashed to the roof penetration using code compliant E2/AS1 methods and wrapped with a building this point it is essentially weather-tight. (and waiting on the chimney to be installed over top).
Structural support frame for chimney repair and replacement
Imitation lead flashing for chimney support frame

Installation and flashing:

- Once the support frame has been finished and flashed, the replica chimney can then be fitted to the house.

- We use a small crane to lift the chimney ‘module’ up and over the frame.

- Chimney and frame are designed to link together. Once the chimney is in place we finalise all connections, fit the lid and finish the external step flashings.

Benefits include:

  • The chimney and lid are prefabricated which leads to much less time onsite. This is a great benefit for the builder and homeowner with minimal disruption, and a great upside for health and safety…and not so weather dependent.
  • [Important fact] Red Mantle chimneys are easily removed from the roof-line if required.  Removal and reinstatement may be required for renovations or re-roofing.  (We recently had a client do this when they built a new room in their attic).
  • Flashing the chimney to the roof provides the final authentic touch. We use lead, copper, artificial lead (e.g. wakaflex) and colour steel as required.
Lightweight Red Mantle Chimney craned into place over support frame
Auckland repair of chimney using brick slips qpc
Red Mantle Lead Flashing Example
Red Mantle heritage Copper flashing example
Red Mantle imitation lead flashing Wakaflex

Composite and Brick Veneer:

Our brick-slip chimneys are designed with heritage and authenticity in mind. They are constructed using a one-piece fibreglass box that is surfaced with thinly cut brick or stone. Our brick-slip chimneys are indistinguishable from traditional brick and mortar chimneys and are therefore the first choice for heritage restorations.


This is the system required for resource consent compliance in Auckland Heritage zones (see our previous blogs for details)


Te Koraha House Heritage chimney repair after Christchurch Earthquake

Benefits include:

  • Any shape or design can be replicated.
  • Lightweight – at as little as 150kgs, our chimneys are less than 10% of the weight of a traditional brick and mortar chimney which can often weigh more than 5 tonne.
  • Fully functional – We often run flues through the lightweight chimney for open fires and other appliances (and yes - we can flue an open fire!).
Replacement Replica brick slip compositechimney with open fires
  • External step flashings are a standard feature that retain the heritage authenticity.
  • Authentic - 100% authentic brick surface with the ability to use existing, vintage or new bricks. A great solution for heritage-listed buildings by incorporating original bricks/heritage fabric.
  • Quakesafe - insurance companies in NZ recognise Red Mantle as the superior solution for chimney replacements.
  • Engineered - fully engineered and compliant with the NZ building code.
  • Our chimney is a prefabricated one piece structural unit
  • Our chimney methodology is embraced by the Historic Places Trust and the Auckland and Christchurch City Council Heritage Teams as an appropriate solution for chimney replacement and resource consent requirements.

Composite only:

Our composite chimneys are crafted with fibreglass using innovative composite techniques, rigorous engineering, and an eye for design. Brick detail is moulded into the surface using advanced film industry moulding methods. For each style of composite chimney, we have a mould from which we produce that chimney.

Benefits include:

  • Aesthetic - brick detail is moulded into the surface using advanced film industry techniques with extensive colour matching options
  • New moulds can be made if required to suit any new chimney shape and size. (Designs are limited to the current mould stock).
  • Lightweight – at as little as 50kgs, our chimneys are less than 5% of the weight of a traditional brick and mortar chimney.
  • Fully functional – flues can be run through these too.
  • External step flashings are a standard feature that retains authenticity
Fibreglass chimney with realistic brick detail moulded into surface
Full fibreglass chimney replica with realistic brick detail in mould

Lid Details

- Red Mantle chimney lids are mostly constructed with fibreglass, brick veneer and specialised mortars………..sometimes we use stainless steel.

- Our aim is to blend the lid seamlessly into the chimney. This helps maintain the overall look of authenticity.

- All lids are easily removable for servicing.

Benefits include:

  • The chimney is made weather-tight at the top opening by construction of a fitted lid. It is screwed to the chimney and can be easily removed for future maintenance of flues.
  • The chimney lid often will require a chimney pot on top to run flues. The pot/up-stand is made from stainless steel, is part of the lid construction and is 100% water-tight.
  • The pot top opening is flashed using traditional flue flashing cones which allow for safe venting at the top of the chimney.
Chimney lid with imitation terracotta pipe
Cast bronze chimney pots on top of a heritage replica chimney now Quake Proof by Red Mantle
  • If the original chimney had decorative chimney pots, these can be re-instated for authenticity. These can be produced in fibreglass for lightness or in a number of different materials, such as bronze, aluminium or terracotta.
Replica heritage chimney pot on brick slip lid
Copper pot on stainless steel lid for chimney
Terracotta pots on Quake Safe replica chimney