Heat shields for wood stoves and distance to combustibles (2024)

From The Stovefitter's Manual by Julian Patrick

Shielding your wood burning stove so as to protect combustible materials

Heat shields for wood stoves and distance to combustibles (1)

It’s worth following the rules and regulations when it comes to wood burning and multifuel stoves. If you have not used or owned a stove before you might not be aware quite how hot the stove and the flue pipe can get. In normal operation a flue pipe will be at 150 to 250 degrees centigrade but can go a lot higher. If deposits attached to the inside of a flue catch fire then a flue pipe can even glow red (worst case scenario and extremely rare). Building regulations must sensibly cover all eventualities (including a pipe glowing red hot) to protect property and life. The floor underneath a stove or in front of the glass can get much too hot to touch and a suitable hearth is imperative.

A “combustible material” is any material that is not A1 fire-rated or to as high a specification as this (your sofa and that wooden beam are definitely combustible materials!). Plasterboard is officially a combustible material. Materials such as “pink plasterboard” might have increased levels of fire resistance but this does not make them A1 fire-rated (e.g. pink plasterboard might be rated as holding back fire for “x” minutes but this is not the same as A1 fire-rated). A1 fire-rated means that it will not catch fire, full stop, and it will not fall apart in a fire. You are safe with brick, stone and plaster as these are NON-combustible materials.

Stud walls might have wooden battens behind the plasterboard and in this instance normal Building Regulations for combustible rules should be followed (just because the battens cannot be seen does not mean they are safe).

Grey areas?

At the end of the day “who is inspecting/signing off the job?” is the real question and it is these people that need to be kept happy. If in doubt err on the side of belt n braces caution.

TOP ADVICE: To make your job very easy just ensure there are no combustible materials anywhere near your stove.

Further down this page look at the rules for the following:

  1. the stove
  2. the vitreous pipe
  3. twin wall (insulated) flue

Want to build your own chimney breast or fire surround? Google "building fireplace surround Promafour"

Wood burning stove rules

Heat shields for wood stoves and distance to combustibles (2)Your stove must be a minimum distance away from combustible materials. This distance will be specified by the stove manufacturer in their installation instructions (contact them if stove not yet purchased). The distances will often be 40cm or more (if you have an inglenook with any combustibles present then it better be a large one). Remember this is to combustible materials.

Can you shield the combustibles from the stove and reduce the specified distance? Yes you can.

If the stove does not exceed a nominal heat output of 7kW then yes (https://www.hetas.co.uk/bs8303-standard-update/)

Heat shields for wood stoves and distance to combustibles (3)

Heat shields for wood stoves and distance to combustibles (4)

Heat shields for wood stoves and distance to combustibles (5)

Some caveats with heat shields

If the following caveats are met then clearance to closest combustibles can be reduced to 95mm between stove and heat shield (see diagrams).

  • Stove must be under 7kW nominal
  • Shield must be a min 1.5mm thickness galvanised steel (can be painted afterwards to match wall) and affixed with non combustible fittings (e.g. Thunderbolts with copper plumbing pipe cut for spacers)
  • Shield shall be open top and bottom to allow flow of air
  • The shield must extend at least to the hearth edges and at least 300mm above the top surface of the appliance
  • There shall be no protrusions above the shield to prevent air flowing behind the shield

Heat shields for wood stoves and distance to combustibles (6)

Heat shields for wood stoves and distance to combustibles (7)

Don't want to bother with a heat-shield?

The 4kW Saltfire Scout has a supplied rear heat-shield and this ensures a very low distance to combustibles at the rear of the stove of just (100mm) 4").

Heat shields for wood stoves and distance to combustibles (10)

Heat shields for wood stoves and distance to combustibles (11)

Hetas's diagram (for comparison with the above) is here.

For a very good but expensive shield see Vlaze at foot of this article.Heat shields for wood stoves and distance to combustibles (12)

Note that some stoves can be fitted with a heat shield direct onto the stove (provided by the stove manufacturers). The DG Ivar 5 stove has a distance to combustibles at the rear of 400mm but fit their heat shield directly to the rear of their stove and this is reduced to 150mm. The Ekol Applepie also has an optional purpose built enclosure.

Stoves and non-combustible materials: read the manual

What appears to be a complete mystery when it comes to Building regs, most installation guides and stove manuals is minimum VERTICAL distances to combustible materials (usually a wooden beam or lintel).

BS1251 says

3.1.4 – Wooden Mantels

“Where a fireplace consists of a marble, stone or ceramic back panel and hearth together with a wooden mantelpiece. There shall be a clearance to combustible material of 300 mm above the fire opening and 150 mm either side of the fire opening to the start of the wooden mantel. Extra clearance may be needed when the fireplace is constructed for certain types of appliance”

This advice therefore should be followed as ‘good practice’ in lieu of no other directive.

Ekol Applepie with own enclosure

Steel flue pipe (vitreous pipe, usually black) rules

Steel flue pipe (often called vitreous pipe) is the pipe that comes out of the top of the top or rear of the majority of stoves.

Flue pipes GET EXTREMELY HOT and should be located as to avoid igniting combustible materials. See clause 2.15 and diagram 19 of ADJ (Document J of the Building Regulations).Heat shields for wood stoves and distance to combustibles (14)

The key rule for all flue pipe is that:

Any combustible material must be three times “X” away from the flue pipe where X = the diameter of the flue pipe.

This means that your 5″ flue pipe should be 15″ away from combustibles and your 6″ flue pipe should be 18″ away from combustibles in any direction.

This distance can be halved if you shield the combustible material.

The shield must, of course, be non-combustible (do not use plasterboard as it is not A1 fire-rated and may gradually crumble).

There must also be an air gap between the shield and the combustible material of a minimum of 12mm (other wise the combustible material soon ends up the same temp as the shield).


The air gap is very important – just sticking the shield to the combustible material does not work as the heat just passes through the shield. Air is an excellent insulator.

Vitreous and non-combustible materials: close as you like.

Shielding wood beam from stove or steel flue pipe (vitreous pipe)

As already mentioned it is possible to shield a combustible material e.g.a wooden beam from the heat from a heat source.

As can be seen from the regulations outlined above shielding can reduce the minimum allowed distance between pipe and material to 1.5 X diameter rather than 3 X diameter (5″ pipe when shielded can be 7.5″ away and 6″ pipe can be 9″ away). As a fitter I have one problem with this… I correct myself… the customer usually has one problem with this. As can be seen from the diagram (fig.1) below, in order to be effective the shield always has to drop below the wooden beam. This means the shield can be seen from the room, especially when sitting on the sofa. The amount that is usually showing is 2 to 5″. I usually have to inform customers that they have no choice in the matter.

In the the second diagram (fig.2) the long orange arrow (distance from flue to wood) must be a minimum 15″ (5″ diameter flue) or 18″ (6″ diameter flue). The short red arrows show an area where the gap should be half of this (7.5″ or 9″). The gap between shield and combustible material must be 12mm minimum (BEST PRACTICE 25MM).

In the example below, if the steel flue is 5″, then the two long orange arrows should be 15″ or more whilst the short red arrows should be 7.5″ or more.


Heat shields for wood stoves and distance to combustibles (15)


Heat shields for wood stoves and distance to combustibles (16)

Twin wall flue pipe rules (clip-together chimney systems)

Twin wall flue pipe has a diameter of approx. 2″ more than steel stove pipe due to it being insulated (so a 6″ diameter vitreous would be an 8″ exterior twin wall). It is usually used to pass through ceilings and lofts or run outside of buildings (it is often stainless steel but is also available in black).

Heat shields for wood stoves and distance to combustibles (17)Note that when you purchase twin wall pipe it is the interior size you specify (so our 6" twin wall is 6" inside).

Twin Wall flue, because it is insulated, only has to be a minimum Xcm from combustibles. “X” is usually 5cm, 6cm or 7cm depending on supplier so please check (it might be 5cm in open air and 8cm if “boxed in”). Duraflue Easy Fit should be 7cm from combustibles if boxed in but can be 5cm if in open air. Twin Wall Flue is used to build complete chimney systems where no chimney is present but is also used in place of the usual vitreous steel stove pipe in areas where a combustible material is close by and is often used in place of steel in order to protect wooden beams or surrounds.

In order to bypass a wooden beam one requires, from the bottom up: short length steel vitreous pipe (usually 25cm length), vitreous to twin wall adaptor, length of twin wall (usually a metre or a metre and a half), twin wall to flue liner adaptor, chimney liner. One can choose to go straight to the stove with the twin wall and one would then just omit the short length of vitreous pipe.

Note that joints in twin wall are, according to regs, supposed to be able to be inspected and a suitable inspection hatch fitted (30cm x 30cm minimum). One way of achieving this is to make your closure register plate removable in some form (even if removing it is a pain at least you have complied).

Twin wall and non-combustible materials: close as you like.

Heat shields for wood stoves and distance to combustibles (18)

Heat shields for wood stoves and distance to combustibles (19)

Heatshields for wood stoves

Heat shields for wood stoves and distance to combustibles (20)Plasterboard walls are classed as combustible in Building Regulations and very often cause problems when striving to follow the rules AND YOU WILL LIKELY REQUIRE A HEAT SHIELD AS ALREADY DISCUSSED.

A company called Vlaze launched “aesthetically lovely” heat shields (see pic below). “VLAZE wall mounted heat shields are designed to be hung behind a wood burning stove creating a focal point that not only enhances the fireplace but allows the stove to be placed close to the wall behind. When installed the shield reduces the stoves distance to a combustible material by half and in the case of Charnwood appliances down to just 100mm”.

Vlaze panels are however very heavy and expensive (£300-£500). One might agree that they are somewhat over-engineered. If you are prepared to put the funds and effort into Vlaze – they are rather lovely.

You can make your own heatshield from steel or Hardiebacker board (Google it). Just use metal tubing as spacers (e.g. copper pipe or even a stack of nuts or washers will do). Then paint the shield same colour as the wall with standard water based emulsion(or some spray it with black stove-spray or bbq paint).

To find stoves that come with a built in heatshield use our menu to view all our stoves and from the left hand filter menu choose "Rear Heatshield Possible".

Heat shields for wood stoves and distance to combustibles (21)

By Julian Patrick

Julian Patrick is the author of The Stovefitter's Manual and an experienced wood burning stove installer (including solid fuel heating systems).

Laid down tools in 2013 to write The Stove Fitter's Manual and open a small shop in North Wales (the Wood Stove Hut). Launched Stovefitter's Warehouse soon after due to fast growth of sales.

Own stove is a DG Ivar 5.

We will happily strive to match any price you may have from any other supplier as long as the other supplier has it in stock.
Offered an "ex-display" or "shop soiled"? We will strive to offer you a new stove for the same price.

Heat shields for wood stoves and distance to combustibles (39)

Stovefitter's Warehouse is owned and managed by Julian Patrick, blogger and author of The Stove Fitter's Manual. Julian was previously a full-time installer of all types of log burner (including solid fuel heating systems). He laid down the tools in 2013 to write his stove manual and open a small shop in North Wales (the Wood Stove Hut, soon to grow into The Stovefitter's Warehouse).

Heat shields for wood stoves and distance to combustibles (2024)


Heat shields for wood stoves and distance to combustibles? ›

The primary instance in which you'll need to use a heat shield, is if you're installing a stove in a confined space. The Fire Protection Association recommends that common radiant-style stoves should be placed at least 900mm (36 inches) away from any combustible surfaces.

How close can a wood stove be to a heat shield? ›

Heat Shield Construction Rules

Minimum clearance along the top of shield at ceiling: 75 mm (3 in.). Shield extension beyond each side of appliance: 450 mm (18 in.). Shield extension above appliance: 500 mm (20 in.). Edge clearance for ceiling shields: 75 mm (3 in.).

How close can a wood stove be to combustibles? ›

Clearances from walls. Stovepipes, like stoves, radiate heat. If they are installed close to combustible materials, a fire can result. The NFPA recommends that a stovepipe be at least 18 inches from the nearest combustible material.

How far does a wood stove have to be from the wall with a heat shield? ›

Do I need a heat shield for my stove? The Fire Protection Association recommends that the common radiant-type stove must be spaced out by 900mm (36 inches) from a combustible wall. Using a heat shield can reduce the space required to 95mm as stated by HETAS.

Can cement board be used as a heat shield? ›

Strong, durable and resistant to water damage, DUROCK® Next Gen Cement Board is ideal for use in partitions, walls, floors and ceilings in residential construction and can be used as a heat shield.

What can I use for a heat shield behind a wood stove? ›

Heat shields can be made from a number of different materials. These include brick, stone, tile or vitreous enamel. What's important to bear in mind, however, is that the heat shield is fitted with an air gap between it and the wall surface behind it.

What is the minimum clearance above a stove to combustible material? ›

Household cooking appliances shall have a vertical clearance above the cooking top of not less than 30 inches (760 mm) to combustible material and metal cabinets.

What is the low distance to combustibles on a stove? ›

This is about giving the stove sufficient space around it to both radiate its heat properly and to prevent the stove overheating, which may damage it. This minimum distance is seldom less than 2" (50mm) to the sides or an inch (25mm) to the rear.

How far should combustibles be above stove? ›

Whilst there is no legal definition for what this must be, as the manufacturer we suggest that stoves should be installed with a minimum of 100mm clearance to non-combustible materials all around the appliance.

How wide does a heat shield need to be? ›

Building Heat Shield – Compliance with CSA B365. construction, materials and clearances you will need to reduce your distance to combustible walls. The main clearances shown are; heat shield spacing from wall 7/8 inch, shield must extend 18 inches from side of appliance, and shield must extend 20 inches above appliance ...

How close to a wall can you place a wood stove? ›

The National Fire Protection Asso- ciation (NFPA) has developed standards for clearances from walls and ceilings that are the basis for many local building codes (Table 1). All combustible materials, wood- work, unprotected walls, furniture, firewood, etc., should be no closer than 36 inches to a wood stove.

What is the best cement board for heat shield? ›

The industry's solution for heat shields

To minimize that distance, the use of an approved PermaBASE cement board heat shield installation will reduce the clearance required by as much as 40%. PermaBASE cement boards are the industry-preferred choice.

How close can a stove be next to a wall? ›

Gas ranges require a 6" side wall clearance above the counter height for proper distance from combustible surfaces. Select models may only require a 3" left side wall clearance based upon the burner configuration.

Can you vent a wood stove straight out the wall? ›

There are 2 basic ways to vent a wood-burning stove, (1) straight up and out the ceiling or (2) out the wall and along the side of the house.

Does a wood stove pipe have to go straight up? ›

The male end of the stove pipe for wood burning should always point down and/or pointing at the stove. Also, the wood stove pipe should always be inserted into the collar of the wood stove outlet. This may sound backwards considering the direction in which the flue gas is traveling.

How close can a wood stove be to a metal wall? ›

The National Fire Protection Asso- ciation (NFPA) has developed standards for clearances from walls and ceilings that are the basis for many local building codes (Table 1). All combustible materials, wood- work, unprotected walls, furniture, firewood, etc., should be no closer than 36 inches to a wood stove.

How close can a stove flue be to a window? ›

If you have an openable window in your roof and the flue will be within 2300mm either side of it or anywhere below it, then your flue system must rise above the window by 1000mm.

How close can a wood stove be to cement board? ›

A combustible floor must be protected by a non-combustible material (like tile, concrete board, or certified to UL-1618 or as defined by local codes) extending beneath the heater and a minimum of 6" from each side and minimum 16" from the front face of the stove and minimum 6" (or the rear clearance to combustibles ...

How do I protect my walls from a wood burning stove? ›

Construct the heat barrier with non-flammable materials like sheet metal. Construction professionals usually mount the heat shields on spacers, 1 inch (2 cm) from the wall. Add a rear heat shield to a stove to limit clearance while protecting the walls.

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