Last winter I insulated the middle floor of my house. Using internal wall insulation with breathable materials that work with the stone I turned my cold crumbly rooms into two toasty warm rooms, using passivehouse style techniques and insulation "on the hard" directly onto the stone I gained space and ensured the walls should stay strong for years to come.
More house projects on these Twitter theads:
Building a drain around the outside to keep the stone dry
https://twitter.com/jriddell/status/1362507482204143619
Insulating the top floor
https://twitter.com/jriddell/status/1354528361851351041
#insulation #passivehouse #passivhaus #scottishhomes