The upper extension is divided into two separate volumes. The first, 7 metres high, corresponds to the future second and third floors of the house and is located at the street level. This part contains two levels of bedrooms (two per floor). It leans up against the building on the ground floor at number 20, rue Thibouméry, in a certain way extending its parapet level. With the width of the plot and an average depth of 5 metres, the extension accommodates a rear fault line, the main purpose of which is to improve the interior lighting of the two lower levels of the house as well as the rooms of the dwellings overlooking the small neighbouring courtyard. The second part is located at the north-east corner of the plot. It is 4.10 metres high in relation to the deck of the roof terrace and is partially truncated so as not to obstruct a secondary view from the bedroom located in the large gable wall. This part, which is higher than the first, is almost invisible from the rue Thibouméry. It combines the exits from the staircase and the lift giving access to the house’s roof terrace.