A pitfall to consider for anyone planning to build your house:
* windows and door-windows! *
Best deals on windows available at Castorama or other large stores need to be factored in at the planning stage.
http://www.castorama.fr/images/products/h/h_628016.jpg
While the height and width will affect the plan (drawings), there is a less noticeable parameter of tremendous importance: the thickness of the window frame ('dormant' in French). All you can find in big stores are 60 to 100 mm frames. Meanwhile, the frame thickness must match your thermal insulation prescribed by the RT2012 study. Or - vice versa - when requesting your RT2012 study from a specialist, tell him that you want to stay within 50 or 90 mm for the insulation (reserve another 10 mm for plasterboard), and that will allow you to buy window products off the shelf. Foil blanket seems to be the material to go for in RT2012. Folks, if somebody can comment or knows other alternatives - kindly write.

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