I am not sure if you offer advice on an individual basis but I have tried a number of forums and haven´t received any replies. If you are unable to help me, I would be very grateful if you could suggest a site that can.
I am currently living in an 30 year old spanish summer house built to very poor standards. We live in the house all year round and it can get particularly cold in the winter. The roof consists of 15 centimeters of poured concrete with black slate tiles on top. I would like to improve the insulation of the house and I was thinking of attaching sheets of solid insulating foam under the current roof and then covering it with planks to give the effect of a wooden ceiling. I have a maximum of 10-12 centimeters to work with (before the ceiling becomes uncomfortably low) and so I would need to use an insulating material with a very high R value.
I would be very interested in your opinion of this plan and your view on its effectiveness. Also any recommendations regarding materials and ensuring adequate ventilation would be greatly appreciated.
Thank you again for your help.