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CROSS Safety Report

Advice wanted by amateur builder

Report ID: 125 Published: 1 January 2009 Region: CROSS-UK

This report is over 2 years old

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This notice, seen by a reporter, was posted on a DIY website, and whilst it may be apocryphal, it illustrates the type of queries received by local authorities and building regulations officers.

Key Learning Outcomes

For homeowners:

  • It is important to recognise and know the boundaries of your expertise and work within the limits of your competence
  • Be aware that Health and Safety legislation places duties on individuals as well as companies to ensure that they do not put people at risk of harm

Full Report

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The Full Report below has been submitted to CROSS and describes the reporter’s experience. The text has been edited for clarity and to ensure anonymity and confidentiality by removing any identifiable details. If you would like to know more about our secure reporting process or submit a report yourself, please visit the reporting to CROSS-UK page.


This notice, seen by a reporter, was posted on a DIY website, and whilst it may be apocryphal, it illustrates the type of queries received by local authorities and building regulations officers.

Hi All

I am removing a supporting wall between the old exterior of the house and the new 'lean-to' extension. Because the 4m lintel will be fitted into the ceiling cavity I can't needle it but will be using four strongboys on the outside and three acros supporting the ceiling on the inside. I will also have a couple of temporary acros to use directly under the wall. The wall is a concrete block cavity wall. I have spoken to builders and structural engineers so basically know what I am doing but am taking it slow - for obvious reasons. I am interested in any general advice (apart from 'get a builder in!') but have two key questions:

1. How high above the lintel should I be putting the strongboys - I have heard 18 inches but can this be more or less?

2. Can the strongboys be used to support just the outer skin? Because the inner skin is tied to the outer and sits on the joists and the joists are supported on the inside would this be enough or do the strongboys have to go through both skins of the wall?

I have a system in ready to lift the lintel into place, but the awkward bit will be getting it between the support piers and the strongboys at the top. Is it ever an option to lift the lintel into place and then build up the support piers and the concrete cap with the lintel already there?

Many thanks for any help and for reading this far!

Expert Panel Comments

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Expert Panels comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-UK Expert Panels page.

The message, which is true from large to small structures, is that the loading conditions during construction can be complex and demanding. Temporary works require a proper understanding of the load paths and a proper check of the structure’s strength and stability during all stages of building work. Failure to make such checks risks structural failure and personal injury.

The amateur builder here is clearly incompetent to do the work and is operating outside the statutory requirements of safety legislation such as the Building Act and Health and Safety at Work Act. They have a civil duty of care, of which they are probably unaware and risks criminal prosecution and the possibility that the house could suffer a partial or even total collapse. See CROSS reports 123 and 128 for the dangers of not getting it right when working on domestic properties. However, the writer on the web site recognises that they need help although this is an unconventional way to ask for it.

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