Strong gales can cause damages to buildings by lifting their roofs. The work by Siegmund (2015) suggests a method for a dynamic redistribution and redirection of wind force for securing buildings from damage as occasioned by hurricanes and the like. It is based on a semi-permeable textile membrane to counteract the aerodynamical uplift. The apparatus comprises a textile net or mesh of predetermined air permeability which acts as a semi-permeable membrane for strong winds. It can be positioned over the building, is fixed with anchors to the ground and can be removed easily. We introduce and study an elastic model which explains how the forces on the roof depend on the wind permeability and elasticity of the textile membrane, the angle of the roof, as well as on the angle of the membrane. The computations show that the semi-permeable textile membrane redirects and neutralizes a portion of the wind forces during periods of gales.