Hi all, I've had some great advice on here before so I hope people don't mind helping me again.   Have started on a new room now for insulating with wood fibre board. I have used both Steicoflex (flexi wood fibre) between battens and Steicotherm (rigid wood fibre) in the first chunk of the house done so far, and very pleased with the results already.    The new room has a fireplace and chimney on an external wall. It's a  solid brick wall. 1920s house, detached, East Ang