Concrete and masonry defects

Question 1

What is the name given to the defect affecting buildings with a steel frame and stone facade?

Answer 1

Regent Street Disease or Deansgate Disorder

Question 2

What might be the signs of Regent Street Disese?

Answer 2

Vertical cracking to columns and horizontal cracking to beams. The cracking mirrors the arrangement of the members on a building.

Question 3

What are the remedial measures for Regent Street Disease?

Answer 3

Cathodic Protection

This involves the installation of an electrical system which applies a DC current to reverse the direction of the current between the environment and the frame from a positive, rust-forming flow to a negative flow. This will arrest the formation of rust although it does not reverse previous corrosion

Question 4

How does Regent Street Disease occur?

Answer 4

Porous masonry allows water to enter the building. The steel frame corrodes, and expands, pushing outwards on the facade and causing the stone or masonry to crack and break off eventually.

Question 5

Which buildings are affected?

Answer 5

Primarily pre 1950’s buildings
Steel framed buildings with a masonry facade
Steel frame doesn’y have a sufficient gap between the frame and the facade