Hoop Iron Survey & Report

Cadalot Services Ltd  have considerable expertise dealing with problems associated with Hoop Iron Reinforcement. 

Alan Wooldridge founder of Cadalot Services Limited was a Senior Structural Engineer at the London Borough of Sutton and undertook the initial investigation into the problem in conjunction with a one of the Local Authorities building maintenance team when the Hoop Iron issue first came to light on the St Helier Estate in Carshalton and Morden.

During the 1920's and the 1930's a number of properties throughout the UK were built using Hoop Iron Construction, which is a solid metal strip used to reinforce cavity walls along horizontal joints, as Bed Joint Reinforcement.

The reinforcement was generally inserted into end terrace properties, and into some mid terrace properties. This reinforcement was not laid along every joint, usually in the 4th or 6th joints.

Metal embedded in mortar is protected from the rain, but over time the pointing weathers and can breakdown and allow moisture onto the metal.

All ferrous metals such as iron and steel have a tendency to rust when exposed to water. Rust occupies a greater volume than the parent metal, which can expand up to ten times its original thickness. This expansion, if sufficiently large, can crack the brick joints horizontally in a similar way to cavity wall tie failure.

Alan has many years experience dealing with this problem, and undertaking inspections and report, if you would like to find out more about Hoop Iron, or commission a survey then please contact him 07775757068.


There are removal companies that offer to undertake hoop iron surveys at knock down prices, they do not produce a Structural Engineers Report and don't always scan all the external walls in a property. Not all mortgage lenders will accept a letter from a removal company as proof that no hoop iron was found, and RICS Homebuyer reports usually advises that an experienced and qualified Structural Engineer be employed to undertake the survey.  

Any prospective purchaser should check what is acceptable with their lender before commissioning a removal company to undertake the survey. There are occasions where Cadalot Services Limited have had to be appointed after a removal company has already been paid and has found hoop iron, but has not produced a comprehensive report. What is supplied to the client is only a quote for the Hoop Iron removal. Generally they do not employ structural engineers and are unable to provide such a report.  

Hoop Iron certificate were agreed as being Structural Engineers reports certifying what was or was not found as a result of a survey carried out in a prescribed fashion with agreed metal detectors. In early days the engineer would also re survey and certify that all of the hoop iron had been totally removed by the contractor, later mortgage lenders accepted a letter from the removal company stating that they had removed all of the hoop iron, and the scars of the removal are always clearly visible.