Survey of balconies

Causes of damages

The most common cause of damages to concrete balconies is reinforcement corrosion. Corrosion can occur through carbonation, which is a chemical reaction between the carbon dioxide in the air and alkaline components in the concrete so that the pH of the concrete drops. When the carbonation has reached the rebars, these begin to rust, if the concrete is sufficiently moist. Reinforcement corrosion can also occur if the concrete contains chlorides above a certain critical content. The corrosion products (rust) have a much larger volume than the original steel, which causes so-called rust blasting. The concrete top layer outside the reinforcement thus cracks and falls off over time.

Damage to concrete balconies may in some cases also occur by the concrete freezing if it has insufficient frost resistance.

The most common reason why steel-framed balconies need to be repaired or disabled is damages to the load-bearing steel beams. The attachment of the steel frame to the wall is the most mechanically stressed point in the entire balcony structure. To ensure that a steel frame balcony is safe, all beams must therefore be exposed for inspection, even a bit into the façade.

Method

RISE's surveys of balconies usually consists of visual inspection, damage mapping, measurements of covering concrete layers and carbonation depth, as well as chloride sampling (random sampling). On steel frame balconies, inspection of steel beams is sometimes also carried out, usually during renovation of balconies or facades (costly).

Delivery

RISE inspections are usually compiled in verified reports, which usually include condition assessments and proposed measures.