We were recently contacted by Whitefriars Housing Association in Coventry to investigate why areas to a High Rise Tower Block had been spalling.

Our Specialist Rope Access Team attended the High Rise Tower Blocks and carried out a preliminary Safety Defect Survey and Report. This report was used to identify potentially unsafe material that could cause severe harm to both residents and members of the public should any dislodge from the building.

Our Rope Access Team, supervised by our IRATA Level 3 carried out another survey, this time, a Delamination Survey with removal of potentially loose substrate from the elevations.

How does Delamination happen?

When fresh concrete is placed and compacted, the solids (cement and aggregate) settle.

This natural settlement causes excess mix water and entrapped air to be displaced (called bleeding), and the lighter materials migrate toward the surface.

If finishing operations start prematurely and close or seal the surface before bleeding is completed, air and/or water are trapped under the densified surface mortar.

As concrete hardens, subsurface voids develop where the water or air is trapped.

These voids create weakened zones right below the surface that can eventually detach during slab use. Very thin mortar layers over delamination may even detach when struck with a hammer, as you try to sound out the extent of the delaminated area.