By Julian Patrick
By Julian Patrick
A closure plate and a register plate are not the same. A register plate is used when a chimney has no stainless steel liner. It closes off the chimney at its base, just above a wood burning stove. It acts as a barrier to prevent the smoke and fumes in the chimney entering the room. The register plate must therefore make a sturdy seal between the room and the chimney and MUST be made of galvanised or stainless steel (or other non-rusting metal) at least 2mm thick.
Why does it need to be made of metal?
Well if a register plate failed then smoke could enter the room. This could happen, for example, if a brick fell from inside of the chimney.
A register plate will usually have access doors to allow the sweep to access any chamber above it to remove fallen soot.
It is rare nowadays that chimney liners are not fitted (although stove flue pipes might be connected directly to pot lined chimneys) and therefore register plates are less common on new installs. Modern wood burners are highly efficient and this means that LESS heat goes up the chimney. It is the heat that gives the draft (hot air rises and the hotter then the faster it rises).
The more efficient the stove the less heat is wasted up the chimney and the more likely that a liner, rather than a cold void, will be what the stove requires to function correctly.
“Avoid the void” is a common expression heard on stove installer training courses.
A closure plate and a register plate are two different things but do a similar job. A closure plate is used when a chimney liner, containing flue gases, is present. The closure plate is therefore only required to seal the chimney for cosmetic reasons, to stop soot old soot falling on the stove but also to stop heat disappearing up the chimney and being wasted. If a closure plate developed a fault (e.g.hole) smoke could NOT enter the room.
A closure plate can be made of any non-combustible material. In the picture on this page the closure plate is made of 12mm Hardiebacker concrete board which is arguably much easier to cut than metal. Hardiebacker available from Travis Perkins/B&Q etc. about £12 a sheet 1.2m x 0.8m.
HardieBacker® 12mm cement backerboard (previously named HardieBacker®500) has been evaluated in accordance with the protocols and acceptance criteria of EN 12467 and was found to be compliant. HardieBacker® 12mm cement backerboard is fire rated class A1, meaning the product is non-combustible. HardieBacker® 12mm cement backerboard is CE approved and BBA certified since May 2004.
You have a stove and it is connected to a vitreous pipe and this is connected to a chimney liner. The liner connects in the correct way to a chimney pot or cowl.
I do not believe that there is anything in Doc J of the Building Regulations says that you must have a closure plate (unlike a register plate which is a must have if there is no liner).
It is a very good idea though. Chimneys cam smell sooty. Soot can fall from the old chimney onto your wood burning stove. The chimney may draw air from bottom to top (finding gaps around the cowl) and this is all draw denied to your stove.
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.
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 wood burning stoves (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).