RSJ Crack-Help

jd93

Hi,
We've recently moved into a 1970s property. There is a beam running through our living room where a supporting wall once stood.

There was a small crack in the rsj and we highlighted it to our building surveyor. They reviewed it and explained that:

" I don’t think this is anything structural other than perhaps a bit of differential movement, although it might even have been caused when the plaque was fixed over the arch. Fill the cracks and redecorate."

It was covered in woodchip paper previously and the crack appeared small. We have removed the wood chi paper and exposed the extent of the cracks and are concerned. Please see the images attached.

Please advise where possible severity and best actions, we are first time buyers.

Thanks

James

jd93

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FreeBear

The only way an RSJ will crack is if it had been welded together out of two or more pieces. It is highly unlikely that a welded RSJ would pass muster for building control.

What you have is cracks in the plasterboard covering the RSJ - You have a choice of two options. Put scrim tape over the cracks and skim with plaster and watch the cracks reappear in a few years time. Remove all the plasterboard and start again from scratch.

Filling the cracks and papering over would be a short term "fix" and would last a couple of years or so.

jd93

Hi thanks for the fast reply. It could be a concrete lintel, does this change the situation? All i know there was two rooms made into 1 and a beam appears to have been used.

We have a plasterer coming this week to skim over which is why he had to remove the lovely wood chip paper that was fused to it !

FreeBear

In your second image, there is a hint of steel along with some rust staining. Poke it with a screwdriver (other sharp implements available) to confirm.

If it is a steel reinforced concrete beam (unlikely), and the cracks go in to it, you'll need a structural engineer to advise on repair.

Mr.Generous

Use a magnet to test for a steel

Fire_Fox

Did you have a full structural survey? If so send your photographs to them, and ask for comments.

I also suggest not plastering over until you are comfortable there are no underlying problems.

stuart45

It may have metal lathing used to form the bottom and arches. You can get corner pieces, such as Expamet, and then other pieces for the rest. The thickness of the plaster at the bottom suggests this may be what has been used. Above could be plasterboard.
The older galvanised ones were quite prone to rusting, which expanded and cracked the plaster.