We are having a mansard extension done. The stair/hallway area has a triangle of new brick that is exposed to the outside - see images, the old dark brick adjoins with neighbours loft.
Builders plan to just render that area, leaving a large cold spot. I'm asking them to use insulated plasterboard, at least over that new brick area that is external facing. They are not keen, they argue it's not necessary and will stick out.
The existing rendering is typically 20mm to 25mm (see photo side edge of plaster), but there are a few 35mm places too, around the middle of the separation line.
So I know typically 37mm insulated plasterboard is recommended. Wonder if I drop it down to 30mm or 27mm insulated plasterboard, will that still be effective enough? Am I being reasonable in hoping the plasterer can hide the difference? Without hopefully having to take off the dado rails.
Do I insulate to the triangle line, or do I remove the render and square if off. Squaring off, gives nice neat horizontal line to repair, if there are cracks in the future, but risks exposing unknowns and having to remove far more than we intended.
Builders plan to just render that area, leaving a large cold spot. I'm asking them to use insulated plasterboard, at least over that new brick area that is external facing. They are not keen, they argue it's not necessary and will stick out.
The existing rendering is typically 20mm to 25mm (see photo side edge of plaster), but there are a few 35mm places too, around the middle of the separation line.
So I know typically 37mm insulated plasterboard is recommended. Wonder if I drop it down to 30mm or 27mm insulated plasterboard, will that still be effective enough? Am I being reasonable in hoping the plasterer can hide the difference? Without hopefully having to take off the dado rails.
Do I insulate to the triangle line, or do I remove the render and square if off. Squaring off, gives nice neat horizontal line to repair, if there are cracks in the future, but risks exposing unknowns and having to remove far more than we intended.
