Inspection of a Manta floor

Manta floors were installed in certain homes built between 1965 and 1981. The use of calcium chloride in the concrete during the production process can cause rust to form on the metal reinforcement. Over time, this rust can cause chunks of concrete to break off, reducing the strength and thus the safety of the floor.

100% certainty about the technical condition and state of the floor and its reinforcement can only be achieved through further inspection. During a follow-up inspection, all elements and ribs, one by one and meter by meter, must be meticulously inspected from the crawl space underneath the floor, in all compartments, and tapped with a metal object.

Much less so than, for example, a screed floo , these floors also sometimes use calcium chloride as a (drying) accelerator added during the production of the elements. The calcium chloride causes the reinforcement to rust away, and it can no longer adequately absorb the tensile forces. The corrosion process causes the reinforcement in the Manta floor to expand and crush the surrounding concrete. The load-bearing capacity of the ribs decreases, and the Manta floor can fail. This problem is also known as "concrete rot."

• Dato factory floors are visually indistinguishable from Manta floors. You can find the floor's brand name on the so-called "headboards," if they are present.
• It is certainly not the case that calcium chloride has been used in all risk floors and that these are therefore by definition floors on which concrete rot will occur at some point.
• Read our BLOG about the risks of a manta floor

If any defects are found in the floor's ribs, they must be repaired. However, we recommend a follow-up inspection by a specialist company. They will knock down all the ribs on the floor and examine them thoroughly. Only then will the total extent of the damage be clearly visible and a well-founded repair estimate be prepared.

• Because this is a high-risk floor, the crawl space and the underside of the floor must be absolutely dry. The crawl space must also be properly ventilated.
• In many cases, after careful examination, it turns out that rust on the reinforcement is more present than is currently visible. Generally, the repair costs are lower than expected.