Facade-layout synthesis is a combinatorial problem that arises when insulating buildings with rectangular parameterizable panels. At the core of the problem lies the assignment of size to an unknown number of panels and their arrangement over a rectangular facade surface. The purpose of this communication is to give an overview of the facade-layout synthesis problem and its reasoning by constraint satisfaction problems. Then, we show the combinatorial characteristics of the problem, its modeling by means of constraint satisfaction and a decision support system that solves the problem using several constraint-based algorithms.