<p>In this work, a new mathematical model for thermoelastic solids with void volume fractions is established by taking into account gas diffusion and moisture transport. The model equations provide a unified framework that integrates the interconnected effects of void volume fraction, moisture, and diffusing gas. Our model is applied to a one-dimensional thermoelastic medium, specifically copper material, where the half-space surface is traction-free and subjected to both an instantaneous thermal shock and time-dependent concentration and moisture conditions. The solutions are derived in the Laplace domain and transformed into the physical domain using numerical inversion via Fourier series expansion. All physical fields are presented in numerical form and accompanied by three-dimensional and two-dimensional renderings for an illustrative visualization of the distributions. These distributions are analyzed to explain how the void volume fraction impacts the response of all thermoelastic physical fields.</p>