In some applications we try to avoid the transfer of heat by convection, especially through monomur bricks. The solution of this problem consist in division the cavity by putting number of columns between the two external surfaces. We've studied heat transfer in different profiles of monomur brick. The results of the numeric simulations are studied by following the two approaches (local and whole). The local approach consists of studying the heat transfer during every cavity. While the whole approach consists of study the heat transfer in whole cavity. The numeric simulation was achieved by following the finished volumes and Fluent program that solves the equations of the mass' conservation, movement and energy. It's clear that the position of columns allows passing from convective regime into conductive regime inside the cavity. The optimal solution is to homogeneous partition by columns. Finally, we've a method allowing as to define the heterogeneous structure (number of columns and their thickness, thickness of a variable cavities).