Hi there,
We have planning permission for a two storey rear and two-storey side extension at our three-bedroom semi-detached home in Hutton, Essex. Planning Permission is approved.

The kitchen walls are to be opened up to create a large open plan kitchen dining area, with a steel beam spanning the width of the house. The beam is a 254 x 73 UC, 6m in length, so a very heavy piece to manoeuvre and install, resting on pier 600 x 215 at one end and a pier 330 x 215 at the party wall side (Party Wall Agreement to be requested from our neighbours).

The builder we have selected is not keen on installing a single beam due to the issues with manoeuvring and installing such a large steel (even though there is sufficient access to the rear of the property, and given that two other builders who we invited to quote said they could install in one length (with genie lifts)). Our Builder is proposing two beams, 6m in length) bolted together.

We have now gone back to our Structural Engineer and asked him about the builders proposal to have two 6m beams bolted together with spacers between, but he has rejected the proposal. Instead, our SE has suggested two beams spliced at approx. 2/3 the way along the 6m span.

As a Chartered Mechanical Engineer, I have a feel for the loading, deflection and potential twisting involved in such beams, but the idea of two beams bolted together with a plate splice detail I have not come across before.

If I’m honest, I would prefer a single beam spanning the 6m but will bow down to the professional advice and calculations of our SE and Building Inspectorate who will need to review and advise the plan.

Are there any pieces of advice you can give in regard to the above?

We also have deep foundations planned (2.4m deep, running back to 2.1m toward the rear of the house) because of a flowering cherry tree located approx. 1m from the boundary up to which we are planning to build the side of the garage wall.

Building Regulations approval is in the process of being sought.

Kind regards,

  • Alasdair Macmillan

    If your engineer is willing to put his name to it then that should be enough. Like you though, I’d be happier with a single beam. Employ one of the other contractors for the beam installation!

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