What could explain delaminating plywood near a party wall?

Delaminating plywood, particularly near a party wall, can often be attributed to conditions that lead to excess moisture. In this case, cold temperatures resulting in condensation are a likely cause. When warm, humid air from interior spaces comes into contact with cold surfaces, such as those adjacent to external walls or party walls, it can cause moisture to condense on the plywood. This moisture can weaken the adhesive bonds in the layers of the plywood, leading to delamination.

While high humidity from neighboring houses could also contribute to moisture issues, it is the specifics of the temperature difference and subsequent condensation that directly affect the plywood's integrity. Pyrolysis refers to the thermal decomposition of materials, which is less relevant in this context. Incorrect installation methods might lead to various structural issues but would not primarily account for the delamination specifically due to moisture from condensation. Thus, the combination of cold temperatures and humid indoor air creating condensation is the most viable explanation for the delaminating plywood near the party wall.