The basic idea of the project is quite clear. However, it is not so clear how to integrate this vegetal layer in the building architecture. There are several problems: supporting elements, accesibility for easy maintenance, irrigation and draining pipes, avoiding direct contact be­tween the plant and the facade, etc. The designs by Biosca & Botey (Fig. 1) are a quite natural solution for these questions. However, it is important to ensure if for the majority of the building users it is acceptable to loose totally or partially the outdoor vision. To some users, the presence of the creeping plants may be uncomfortable or even claustrophobic, if

they are too dense. A high density of creeping plants covering all the transparent areas of all the building wont be acceptable except in special situations.

Part of the experiments that are being carried out are aimed to observe the reactions of different users and thus to estimate the maximum vegetation densities that are acceptable. The solutions proposed in Fig. 2 and also in Fig. 3 are based in covering only a part of the facade and/or using vegetation with controlled leaf density. A different approach is used in Fig. 4-left, where a set of vertical shadowing elements orthogonal to the facade are proposed and in Fig. 4-right, where the shadowing elements are hortizontal. The numerical simulations to be carried out after the validation of the numerical model will allow to evaluate the energy to be saved using each of these approaches.