Which material should not be butted tightly during installation?

MDF (Medium-Density Fiberboard) panels should not be butted tightly during installation due to their susceptibility to expansion and contraction in response to changes in humidity and temperature. When placed in contact with one another without any spacing, moisture can get trapped between the panels, leading to warping or distortion over time. This can affect not only the panels themselves but also the overall integrity and aesthetic of the installation.

In contrast, plaster board, gypsum board, and particle board can typically be installed with tighter tolerances. Gypsum board, for instance, is designed with manufacturing tolerances that accommodate some tight butting, while plasterboard can be finished with joints that cater to slight gaps for taping and mudding. Particle board, while also moisture-sensitive, is generally used for applications where tighter alignment is expected. Therefore, recognizing MDF's characteristics is essential in preventing future issues in construction or renovation projects.