How to Install a Wood Heater Chimney

Written by natasha parks
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to Install a Wood Heater Chimney
No existing chimney is required to fit modern flue systems. (chimney image by Harvey Hudson from

Installing a new wood heater chimney can be straight forward if you follow the current building regulations and opt for the highest quality materials affordable. Document L is a set of guidelines that apply to new builds and extensions and relates to the reduction of carbon dioxide emissions from new stoves, flues and chimneys. Reading this document will help to ensure that replacing a chimney meets regulation requirements.

Skill level:

Things you need

  • Double skin insulated flue pipe
  • Plastic cable ties
  • Heavy duty saw
  • Thick gloves
  • Eye goggles
  • Staple gun
  • Single skin flue
  • Floor support plates
  • Internal rafter support brackets
  • Electric drill
  • Wood screws
  • Screwdriver
  • Weatherproof code-4 lead flashing
  • Lead collars
  • Mallet
  • Ceramic chimney pot
  • Cowl
  • Chimney fan
  • Register plate
  • Sheet metal
  • Black stove paint
  • Circular cutting attachment (for drill)
  • Stove putty

Show MoreHide


  1. 1

    Install a double skin insulated flue pipe up to the first ceiling above the heater, to create a class I insulated chimney. The flue gases rising from the heater retain their heat and tar condensation is reduced, which in turn reduces the risk of a chimney fire. Opt for flue piping with an external diameter 2-inches wider than the internal diameter because this indicates a double skin, according to Stoves Online . It's not necessary to build a brick chimney breast with this design of flue.

  2. 2

    Roll back the carpet or remove the flooring in the room above. Take care to hold back any wires that are close to the workspace using plastic cable ties. Locate any gas pipes or water pipes to prevent damage while constructing the new chimney. Cut through the rafters using a heavy duty saw. Wear thick gloves and eye goggles. Make space between the floorboards for the flue pipe by removing or stapling back insulation using a staple gun.

  3. 3

    Push a single skin flue from the first ceiling to the top of the chimney breast, where the chimney meets the external roof stack. Ask for assistance to ensure this is done safely and effectively. Support the whole flue pipe (both double and single skins) every 6 1/2-feet using floor support plates and internal rafter support brackets to ensure it is fully stable. Fix the brackets to the walls and rafters using an electric drill to make the holes. Use wood screws and a screwdriver to secure the brackets.

  4. 4

    Improve the efficiency and longevity of the chimney breast and stack using traditional, weatherproof code-4 lead flashing around the join, between the flue pipe and the roofing material. Slate or tile is a good choice. Purchase ready-made welded lead collars from a hardware store. Fit the collar underneath several roof tiles by lifting them temporarily from their positions. Improve the fit of the lead flashing by tapping it gently onto the surface of the roof using a mallet. Replace the tiles or slates carefully.

  5. 5

    Replace broken chimney pots with new, ceramic pots. Fit a cowl to the chimney pot to restrict damage by nesting birds and the subsequent risk of chimney fires. Add a chimney fan to the system if the draw from the wood heater is not sufficient. Use only specialist chimney fans designed to operate at high temperatures to create artificial draw.

  6. 6

    Complete the chimney by adding a register plate. Fit a ready-made register plate bought from a chimney specialist or make one using 2-mm thick sheet metal, such as steel. Paint the register plate black using stove paint from a spray can, which must state that it is heat-resistant. Cut a circular hole in homemade steel sheets using an electric drill and a circular cutting attachment with a diameter 2-mm larger than the flue pipe diameter. Push the register plate onto the bottom of the flue pipe. Seal the joints using heat-resistant stove putty. Leave putty to dry for 24-hours, according to Rubbed In.

Tips and warnings

  • Remove electrical cables, and avoid gas and water pipes during construction. Cutting through a pipe or cable leads to house fires or electrocution. Heavy lifting can cause strains and injuries. Ask for help if you need it. Wear protective clothing and thick gloves. Wear eye protection when dealing with insulating materials as they can be fibrous, contain glass particles, and be damaging to the eye area.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.