Which aspect is considered when assessing the porosity of surfaces for mortar adhesion?

When evaluating the porosity of surfaces for mortar adhesion, surface texture is a critical aspect. The texture of a surface directly affects its ability to allow mortar to bond properly. A rough or porous surface typically provides more mechanical interlock for the mortar, enhancing adherence. Conversely, a smooth or non-porous surface may hinder adhesion, as there are fewer points for the mortar to grip onto.

While factors like age of the surface and environmental conditions are also important in the overall context of mortar application, they do not specifically relate to the porosity in the same direct way that surface texture does. Age can impact the surface's condition and may influence its porosity indirectly, but it is not a fundamental factor for determining porosity itself. Environmental conditions, such as humidity and temperature, can affect setting and curing but do not alter the inherent porosity of a surface.

Thus, while all aspects could have some relevance in a broader construction context, the surface texture is the primary factor when specifically assessing porosity for mortar adhesion.