Suitable board for fireplace ceiling.

[epsilonGreedy]

My fireplace is wide and after allowing for the central flue supporting base plate I will need to close off the ceiling of the fireplace either side of the flu base plate with some form of sheet.

 

My brickie suggested cement board but the BM has offered hardy backer board also known as tiling board which they claim is fire rated. The fireplace is being designed to accommodate a wood burning stove.

 

Is hardy backer board suitable for the fire place ceiling board. It comes in a 6mm or 12mm thickess in small sheets.

Edited May 26, 2020 by epsilonGreedy

[bassanclan]

Yes 12mm hardie backer board can be used for the celing of a fireplace opening. Depending on size you might have a metal plate up there anyway.

 

This might be a useful start of reading

https://www.stovefitterswarehouse.co.uk/pages/lining-a-fireplace

[nod]

I used a cement board and skimmed it 

The plate covered 30% of it 

[PeterW]

Siniat do a cement board - easier to sit it in the mortar joint as they build the fireplace up

[epsilonGreedy]

15 hours ago, PeterW said:

Siniat do a cement board - easier to sit it in the mortar joint as they build the fireplace up

 

 

Thanks, I went for Hardie Backer because that was available locally.

 

15 hours ago, PeterW said:

 - easier to sit it in the mortar joint as they build the fireplace up

 

It just happens that 5 minutes ago my brickie called me outside to look at the board sandwiched into the latest courses of the chimney breast. The 6mm board had plenty of rigidity for the small span between the main lintels. I had picked up some 12mm board as well to cover both options and will now use that for the vertical tiled lining of the 2nd fireplace.

[PeterW]

Just check the 6mm board has 60 minute fire resistance - easy to cut a slightly smaller piece and drop on top with a couple of blobs of no nails or foam to keep it in place to give a bit of rigidity too if you’re back filling this with Vermiculite.