Typically, concrete spalling and delamination are the result of internal pressure caused by corroding reinforcing steel.
Spalls are areas where concrete has broken away from the wall. Small spalls, or pop outs, can occur at edges where bar ends terminate near the concrete surface or at other localized areas of shallow concrete cover. However, larger spalls occur near embedments and where long sections of reinforcing steel, with insufficient cover, run parallel to the concrete’s surface.
Delaminations are areas where the concrete has not properly bonded with the reinforcing steel. The resulting planar cracks, that run parallel to the surface, are due to corrosion of rebar near the top surface or below embedments. By tapping the concrete with a hammer, delaminations can often be detected. A hollow sound indicates a delaminated area.
Spalls and delaminations on the building facade may be only warnings of more extensive structural damage extending into the building. Repairs inside the building are more expensive, often requiring shoring and bracing of windows or walls, and protection of interior spaces from dust and weather.
Abbot Building Restoration offers effective restoration solutions to these and other masonry problems you may confront. Contact us at 617-445-0274 today.