The problem of fully coupled thermoelasticity in a composite half-space is considered where the composite has variations in its physical properties in one direction only. The resulting one-dimensional problem thus depends on the so-called microscale of the composite. Homogenization of the fully coupled theory provides the leading-order system of coupled equations (independent of the microscale) together with the effective physical properties of the thermoelastic medium. In particular, the effective coupling parameter δ* is found and it is shown to exhibit rather interesting properties; for a range of volume fractions in two-phase composites it is shown that δ* lies below the corresponding coupling parameter for a homogeneous material made up of either phase. Transient boundary-value problems of the homogenized system are then solved and compared with the classical problem of a homogeneous half-space. The magnitude of resulting discontinuities in field variables and their derivatives are found and their dependence on the effective coupling parameter is exhibited.