Insulating fibre board hearth - joints??

[tommo21]

To all,
When laying the insulating boards is there a need or benefit from bonding the individual boards together to stop heat escaping from the joins?
Thanks

[UtahBeehiver]

No, just butt them up tight together. If you use more the one layer then stagger the joints.

[RandyJ]

Ditto.

Randy

[tommo21]

Thanks guys!
I will try and get away with a single 2" or 50mm layer.
In Australia the Calcium silicate board appears to be more commonly available than the Alumina Silicate board.
Any real disadvantage of using Calsil instead of the specified Alsil in the FB literature?
Thanks