Expansive soils swell due to increase in moisture content and shrink when the moisture content decreases. Expansive soils were identified in many locations in Oman causing a severe damage to the buildings. The expansive soil induced damage is more severe in lightweight structures such as residential buildings in Oman which consist of masonry walls supported on shallow foundations. In this study the finite element program (ANSYS) was used to develop a model for analysis of light weight structures. The lightweight structures consist of masonry walls supported on grade beams and subjected to expansive soil movement. The masonry walls were treated as a linear elastic material using three-dimensional stresses analysis. The model allows for sliding of walls relative to the beams. In addition, the model allows for debonding of wall panels along a predefined crack. The model predicts the patterns and the width of the cracks that develop in the walls due to soil swelling or shrinkage. The model was validated by comparison to actual cases of damaged buildings and found to accurately predicts the pattern and magnitude of the actual reported damages to the buildings. Parametric studies were preformed using the model. Many factors were analyzed to determine their influences on the width of the crack. The factors considered are provisions for windows and doors openings, magnitude of heave, pattern of heave, area beneath the building covered by heave, and the flexural stiffness of the building. It has been observed that edge heave causes wider cracks at the bottom of the wall and the center heave causes wider cracks at the top of the wall. The provisions for openings result in smaller cracks. The width of the crack increases with the magnitude of heave. The increments in area covered by heave results in wider cracks. The increases in modulus of elasticity decreases the width of the cracks. The increases in length of the wall results in smaller cracks. The increase in wall height results in wider cracks. Keywords: Expansive soil, Masonry panel model, Soil-structure interaction, cracking.