Because the gambrel roof doesn t go very high above the brickwork you can discover that you do not have enough living space in your attic.
Insulating a gambrel roof room.
To insulate the roof you will need to use a combination of insulation to fully protect the roof.
One of the best ways to protect your mansard roof from the problems of ventilation is to use a vapor barrier on the inside.
If you have an existing house with this style then dense pack cellulose or pour in place open cell foam are your only options.
How to vent a gambrel roof using reflectix.
Step 1 add a vapor barrier.
If you do not want any extra living space in your attic then you can install a low height roof but you will also have a small space to install the insulation and the ventilation system.
This is why careful planning is very important.