Replace a supporting wall with a RSJ

bobby d

Hi ,

I am going to extend my garage by 2 metres which will envolve me knocking out most of the supporting wall and inserting a RSJ to take the load of the roof.

The supporting wall is about 8 metres long and the roof is slate .

Will a RSJ be able to span that length or would I need to install a support in the middle ?

A friend of mine recomended a timber joist but with the length involved I reckon RSJ is the only way ...

does anyone have any experience with doing something like this who could offer me a few pointers .

thanks

kadman

It would be wise to get the advice of an engineer, as to the steel sizes required, to support the roof. It would be considered a wide span, so you might ask your engineer to instruct you on the sizes required, if you place a support midway in the span, as well as unsupported.

I would be reluctant to take friends or neighbours advice on sizes, I would seek a professional input on this one.

Kadman

rooferPete

Hi bobby,

I have to agree with Kadman, 8 metres is a long span for the weight of the roof and the RSJ itself, they can and do bow in the centre over time.

A lot will depend on the original construction type of wall, twin leaf or cavity block and the ability of the foundation to take the weight, as it will no longer be spread over a wide area but on two points that would possibly have called for a pad foundation if this was the original design.

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gregos

they can and do bow in the centre over time

A steel beam should not creep over time in the way that timber does. If this happens, it's a sign of a very serious overloading which I would characterise as structural failure.

Bobby, an 8-metre span is far outside the d-i-y range. This is for a number of reasons, and is not confined solely to the selection of the steel beam size. This is going to be a significant structural member. An rsj will not do the job: you'll need a universal beam, which will need to be sized by a qualified and competent engineer. In addition, you'll need to have the end bearings examined to ensure that they can support all the weight, or can be brought up to the required standard. Also, with all this redistribution of weight, the loading pattern on the foundations is going to be radically different from what it formerly was.

Trust me on this: I know exactly what I'm talking about. Under no circumstances take this on as a d-i-y project. Your friend who thinks a timber beam is ok would be well advised to stick to the day job.

Best wishes,

gregos.

rooferPete

gregos wrote:

A steel beam should not creep over time in the way that timber does. If this happens, it's a sign of a very serious overloading which I would characterise as structural failure.

Emmmm did i leave that bit out ? :rolleyes:

Joking aside Gregos is right, it is too structural to take on using directions from a message board.

I think it calls for a site visit from a person qualified in all aspects of load distribution, an Architect will most likely call in a structural engineer anyway.

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bobby d

hmmm - thanks for info -
I think I will look into getting a engineer and let them handle it .

thanks All

Borzoi

rooferPete wrote:

I think it calls for a site visit from a person qualified in all aspects of load distribution, an Architect will most likely call in a structural engineer anyway.
.

And charge you for their time too - just go to the engineer!