Masonry and render deterioration rectification

Understanding masonry and render deterioration

Masonry fails for reasons that are not always visible on the surface. Mortar joints erode or fret where salts crystallise, render loses its bond to the substrate and sounds hollow when tapped, and bricks above windows and doors drop or step-crack when the lintel behind them corrodes. Corroded or missing wall ties can allow an outer leaf to bow away from the inner wall.

The visible symptom is often a finish problem, such as cracked render or peeling paint, while the cause is moisture moving through the wall, movement in the structure or metal components reaching the end of their life. Repainting or patching render over these conditions tends to fail again within a short period.

How the wall is investigated and scoped

Investigation starts with a close visual survey of the elevations, tapping of rendered areas to map drummy zones and inspection of the details that commonly fail: lintels, sills, parapets, damp-proof course lines and junctions with slabs. Where wall ties or lintels are suspected, DYME coordinates localised openings or specialist inspection with the appointed engineer or consultant.

The scope is then written against what was found, distinguishing areas that need re-rendering from those that need repointing, brick replacement, lintel replacement or tie installation. Access method and the extent of each repair type are established before the works are priced.

How rectification is sequenced

Structural items such as lintels and wall ties are rectified first, because they govern whether the surrounding masonry is stable. Repointing, brick replacement and render removal follow, with render reinstated to a specification suited to the substrate and the exposure of the wall. Coatings and finishes are applied last, once the new work has cured.

Rendered and face-brick elevations are usually worked by scaffold or elevated platform, so the programme is staged by elevation to limit disruption to occupants. For a Sydney or NSW masonry or render enquiry, provide the building location, wall construction if known, photographs of the affected areas, any reports, access considerations, budget range and required timeframe.

Common questions

Can drummy render be patched rather than replaced?

Small, isolated areas can sometimes be cut out and patched. Where mapping shows widespread loss of bond, patching tends to fail at the edges and full removal of the affected elevation is usually the more reliable scope.

How is a corroded lintel identified?

Stepped cracking or a drop in the brickwork above an opening, rust staining at the bed joint and visible expansion of the steel are the usual indicators. Confirmation is made by a localised opening or by the engineer’s inspection.

Will the repaired areas match the existing finish?

Matching is addressed in the scope. New render and pointing can be brought close to the existing texture and colour, and where a consistent appearance matters the scope may include recoating the full elevation rather than just the repaired patches.