House Movement After Steel Beam

[Boyts81]

Hi all

We're in the midst of an extension and the steel was put in place about 5 days ago and we've just noticed some cracks in upstairs wall above it.

I've attached some pictures below but essentially the tiling in the bathroom has cracked in a zig zag shape along the grouting and in one case actually cracked one tile down the middle. Similar cracks in the jointing room along the paint work.

I'm assuming this is fairly normal after removing a whole wall and replacing with a beam but would appreciate any advice on this. Are there any signs that this is more serious that I should be looking out for?

Building control have checked the calculations and inspected the beam and everything was given the green light.

Cheers

 

[^woody^]

I'd say it's a quality of installation issue, or the selected beam has too much deflection - ie the designer should have selected a different beam with lower deflection under initial load.

No, not normal. Common, but it should not have happened in the first place.

 

[Boyts81]

Thanks Woody. So do you think this requires further investigation, i.e. Potentially a bigger problem than just a few cracked tiles

 

[^woody^]

Deflection is just the initial bending of the beam as the weight of the wall above is put on it. It bends a bit, then stops.

If there are fragile finishes above, then a careful designer may select a bigger beam than what would otherwise be used to deal with this. The calculations may well be fine and nothing will fall, but still finishes can crack because of this.

That's one possibility.

The other is that the builders have either pushed the wall up when propping, so as to crack finishes on the way up and then again as it moves back down when the props are released.

Or they have not packed it enough with slate and mortar above the beam, so it drops more than it should.

So if the council are happy with the calculations then it may well be structurally sound. But you are then left with who is going to pay to make the finishes good - and ensure that they don't crack again as the house moves naturally over the seasons.

 

[Boyts81]

Thanks Woody, appreciate the advice. Damage is very minimal and our builder is a reasonable guy so I'm not worried about that so much.

My main concern was safety & the house falling down etc. Will consult with our engineer and building control manager and hopefully get some assurances.