I am considering adding internal insualtion to a house with 9" solid brick outer walls on a room by room basis as I decorate. But on some parts of the house eg the outside wall where the stairs run, I would have to compromise at 25mm (extratherm etc), otherwise the stairs would become too narrow to use.
Does part L require any improvement to insualtion of a wall to comply with current requirements for new build?
Does part L require any improvement to insualtion of a wall to comply with current requirements for new build?