Solid Masonry Wall System

A solid masonry wall is a single thickness of brick, stone or block laid without a separating void and bonded through its depth, so that the whole section acts together. Rain wets the outer face, travels a limited distance inward under driving conditions, then returns outward as the weather changes. The wall is never asked to exclude water at a plane; it is asked to take water in slowly and release it again.

Its parts are chosen to keep that exchange in balance. Units and the mortar between them absorb and release at rates meant to be compatible, with the joint usually the more open and the more sacrificial of the pair. External treatments alter how much water enters, and some of them alter how readily the face can dry as well. Internal plasters and decorations decide whether the section can also dry towards the room.

The distinction from masonry-cavity-wall-system is visible at any opening or breach. A cavity wall shows a void between skins, and its detailing assumes that water crossing the void will fall and be led back outside. A solid wall shows continuous masonry from face to face and has no such route, so moisture leaves only by evaporating from a surface. That is why altering one face of a solid wall changes the behaviour of its whole thickness, while an equivalent alteration to a cavity wall's outer leaf need not.

Load-bearing behaviour, bonding and the way openings are formed belong with loadbearing-masonry-wall-system; this entry is concerned with the wall as an environmental assembly. Older walls of this kind are commonly found carrying later coatings, linings and repairs that were never considered together, and their present behaviour is the sum of all of them.

The relationship that governs this wall is between the unit and the joint. Where the mortar is the more open and the weaker of the pair, moisture and dissolved salts move preferentially through it, and damage concentrates in a material that can be cut out and replaced. Where a repointing mix is made denser than the units around it, that traffic is forced through the faces of the bricks or stones instead, and the wall loses its sacrificial element.

Anything applied to a face is a change to a drying direction, not a change to that face alone. Liquid uptake and vapour movement are separate transports, so a treatment may narrow the wetting route while leaving the drying route much as it was, and which of those a given product does on a given wall is established by whoever specifies it rather than assumed. What the section responds to is the sum of what both faces are doing, and if neither route is left open, moisture accumulates within the thickness instead of showing at a surface where it would be noticed.

The shedding details decide how much work everything else has to do. Copings, sills, projections and the level of the ground at the base control the volume of water arriving on the section. Lose an overhang, replace a sill without its drip, or raise the ground over the base course, and the same masonry with the same mortar is asked to buffer far more water and to dry from a face that stays wet longer. The wall then behaves as though it had been rebuilt in a harsher exposure.