This paper presents an analytical formulation to complement considerable experimental and numerical programs conducted to propose a new timber-based retrofit technique for masonry walls. The formulation is based on the static analysis of an idealised structural scheme adopted in previous experimental tests, and it obtains the bending moment equation which predicts the maximum failure load and its location on both plain and retrofitted masonry walls. Thereafter, the expected failure load in the masonry wall is analytically estimated from the moment of resistance of both the plain and retrofitted walls using ultimate section analysis. The results show that the analytical formulation correctly evaluated the capacity of both the plain and retrofitted masonry wall to within 5% variation. It thus concluded that the developed analytical model can be extended into more complex models and thus fit for a parametric analysis to analyse further the efficiency of the proposed timber masonry retrofit technique.