BACKGROUND Starting analyzing the density as a general issue, (building heights, typology of blocks, system of public spaces,…), in order to understand our area, I realized that the relationship (ratio) between built and unbuilt spaces wasn’t optimal. Just taking a look of the area, in environmental terms, you might think that the ratio between built and unbuilt spaces is better than optimal, but just after zooming in you realize that most of this unbuilt spaces are also private spaces, because there are many low dense buildings, with private free spaces, spread all around the area. But understanding the unbuilt spaces as public spaces, as available spaces for the population, the equation doesn’t work. The residential character of this specific area together with the centralized system of existing public spaces, are giving as a result not only a very poor ratio between the high amount of population living there and the available public spaces within the area, but also a very bad accessibility to this existing public spaces. According to the World Health Organization, the optimal ratio of public space should be 9 m2 per inhabitant. So, taking into account this data, the neighborhoods of Vallcarca i els Penitents and El Coll are above this ratio, but the neighborhood of La Salut, with just 1,75 m2 of public space per inhabitant, even having the Güell Park inside, doesn’t cover this need of public space. MAPPING Considering the existing problematic in La Salut, the map attempts to show the real necessity of public space, the exactly amount of square meters for the existing population, expressed by blocks of the most dense area. Overlapping the blocks (knowing how many people live in each one) with this kind of pixel system (where each pixel represents the 9 m2 needed per person) we can visualize better this problematic issue. PROPOSAL The goal of this analysis and the future proposal is to equilibrate the ratio between amount of people and amount of public space, specifically in this dense area. Due to the absence of so much free space within the city, in order to achieve this challenge, it could be interesting to break with the traditional model of creating public spaces just on the street level (which means more land consumption), and try to colonize some residual spaces such as the roofs of buildings, or the interior of blocks, which nowadays are residual but in fact are very potential. Through these operations we could start talking not only about the concept of semi-public spaces available for the residents of a block, but also about the energetic benefits of having green roofs and courtyards.