Even when the attic of a house is said to be “lost” because the frame is made of W trusses, it is possible to fit it out anyway. There are specialised companies that can make the necessary modifications to the roof structure and the appropriate reinforcements to ensure that the floor is load-bearing.
Nevertheless, the project should be carefully studied and the cost of the construction should be analysed in the light of these considerations. As the number of m2 of living space recovered is small, this extension does not have a strong impact on the property value of the house. However, it does create one or more additional rooms, as well as a space that is necessarily atypical, which, in the end, could generate a crush for future buyers.