Beam not installed to spec, should I be worried ?

[Loz]

Hi,

 

Had a steel beam installed by builder as part of renovation works, and it has not been installed to specification by structural engineer, builder has said it is fine and not to worry but I am as such a heavy beam.  Have good relation with builder and rest of build going well and structural engineer is very good friends with builder so if I call him will be a bit awkward.  Thought would post on here to get peoples thoughts , beam is a big galvanised beam and in SE drawing said 225mm end bearing onto 400mm concrete padstones.  When taking apart the single height extension that was in existence it was discovered the inner skin was a weird breeze block with insulation in middle and would not take weight of beam, was discussed with building inspector who said two options steel posts in a goal post arrangement or build new breeze block pillars tying into original blocks, builder went for latter as guess easier and no need to wait of posts being made.

 

For some unknown reason as was armed with SE diagram and I raised it they went for  300mm padstones and he said will be fine, they lifted the beam in on digger and by hand and it didn't go in central as you will see from the pictures but didn't want to move it due to weight and it was sat well otherwise, they did also knock the front left padstone from its cement when putting it in, builder again said not to worry as all the weight is on the back.  As it didn't go in central one end has 300mm bearing (to end of padstone) and the other 215mm (10 mm short of recommendation).  Not sure if the building inspector will refer to the engineering drawings when inspecting and if picked up will be pretty obvious came from me as questioned the arrangement a few times.  The beam has now had block work done on top of plate and at sides so will be pain to rectify.

 

What do people think, should I be worried, what would you do ?

 

Front:

 

End with 215mm bearing instead of 225mm on 300mm padstones instead of 400mm.

 

End with 300mm bearing  on 300mm padstones instead of 400mm.

 

Side view of one end:

 

Any thoughts greatly appreciated,

 

Many thanks,

 

Lawrence

[PeterW]

That only looks big because of span not weight - the roof is the only load isn’t it or is there some sort of additional wall going above ..?

 

Padstones look like they’ve been cut from a 1200mm concrete lintel hence the size…. Not the best I’ve seen but not the worst - the two lintels with a welded plate will stop it all going anywhere. 

[Loz]

Thanks for quick reply, yes the roof is only thing going back on so not a lot of load other than the weight of the beam which is very heavy, the span is 4.5m and the beam specified was 250x150x8.0 with 275mm 8mm thick bottom plate galvanised.  

In two minds whether to make a fuss as queried it a few times and builder seems experienced and to ask for it to be redone in his view unnecessarily could make rest of build awkward.  I reckon you are right the length of lintel they had probably determined why they went for 4 300 padstones rather than the specified 400mm.

 

Thanks,

 

Lawrence

[Marvin]

More information for you Lawrence.

 

https://www.mcandrewassociates.co.uk/post/padstones-what-are-they-and-how-are-they-used

 

Think the 400 length of each padstone is important.

 

Marvin

[Loz]

Thanks for link, really not sure what to do, so frustrating as would have been very easy to use specified padstones, wander if as important when in same direction of beam as opposed to when at right angles where a bigger padstone would spread load maybe differently- to be honest can’t get my head round it, think speaking to structural engineer even if upset builder is way to go, 

 

Thanks,

 

Lawrence

[Marvin]

I understand. It may have been that the pad stone are not available, I have had all sorts of problems with obtaining concrete items.

 

I agree. If it was me I would be asking the Structural Engineer how important the 400mm length of the pads is. Especially as 300 is only 75% of the original length.  After all you don't want him to fall out with the builder if a problem arises. Better to face it now rather than later...

 

Good luck

 

Marvin

[Marvin]

To be clear its the surface area of the pad stone lying on the blockwork below that is important. A padstone crossing the cavity would be worse because there would be even less surface area on the blockwork walls below. The idea is to spread the load on to a wide enough surface area that the blockwork can cope. 

[nod]

That isn’t going to go anywhere 

Theres very little weight above it 

Personally I think you will really piss your builder off if you ask him to alter it 

[Adsibob]

I think you need to weigh up the possible realistic worst case scenarios:

i don’t think you need to worry about something actually failing, as it looks pretty secure and as others have pointed out here, it is unlikely to move anywhere. SEs often over-specify to cover themselves. So the most likely worst case scenario is that it fails building control. So I would just have a chat with your builder and say to him that as it’s not your area of expertise you hired an Se to design it and that you were therefore surprised he deviated from that design, but you don’t want to cause any unnecessary delays to his schedule, so you are okay with it as long as he is sure the BCO is okay with it and that you will be expecting him to fix it if the BCO raises any issues. That way, it is your Builder’s problem if the BCO raises it.

[Marvin]

9 minutes ago, Adsibob said:

I think you need to weigh up the possible realistic worst case scenarios:

i don’t think you need to worry about something actually failing, as it looks pretty secure and as others have pointed out here, it is unlikely to move anywhere. SEs often over-specify to cover themselves. So the most likely worst case scenario is that it fails building control. So I would just have a chat with your builder and say to him that as it’s not your area of expertise you hired an Se to design it and that you were therefore surprised he deviated from that design, but you don’t want to cause any unnecessary delays to his schedule, so you are okay with it as long as he is sure the BCO is okay with it and that you will be expecting him to fix it if the BCO raises any issues. That way, it is your Builder’s problem if the BCO raises it.

A much better way of dealing with the situation! And I agree with nod.  I just wonder why specify 400mm.

[Loz]

8 hours ago, Marvin said:

A much better way of dealing with the situation! And I agree with nod.  I just wonder why specify 400mm.

 

Thanks ever so much for all the replies, been really worrying me this one, I think a chat with BCO is good way to go to see if he is happy but can't help feeling he will only be happy if the SE says 300 is fine and the 400 was over specified, as was said above 300 is only 75% of the original and at one end the beam goes to end of padstone and was reading (although not entirely sure on this) that load is also exerted at 45 degrees from end of beam and thats why they are specified over length to cater for this.  Would a BCO typically compare what has been done with the SE specification or just eyeball it and say okay from experience/discussion with builder ?

 

Many thanks,

 

Lawrence

[PeterW]

No idea on the 400mm padstone spec on that as I can’t see why it wasn’t just 7N blocks as the load is negligible. I would leave it and move on.  

[markc]

+1 to @PeterW reply. the beam would behave perfectly well with a point support at the very ends. As the loads are very low (no structure or floors above) then the padstones/bearing are also very lightly loaded.

[Loz]

13 minutes ago, markc said:

+1 to @PeterW reply. the beam would behave perfectly well with a point support at the very ends. As the loads are very low (no structure or floors above) then the padstones/bearing are also very lightly loaded.

 

Many thanks, sounding like should just leave it and as you say move on, just the end of the one storey roof (concrete tiles) resting on top of it so happy not much load above, it was the weight of the beam itself I was concerned about as took 10 people to move it - very new to all of this and was worried about a failure as would be very nasty if it came down.

 

Many thanks,

 

Lawrence

[PeterW]

@Loz I don’t know the full spec but doing a quick fag packet, even with a 3.6N block and a reasonable end bearing load, a 225mm padstone is more than adequate. The key is that the beam isn’t overlapping the padstone. It’s also worth noting this is a steel with a flange so the padstone isn't required under the front flange - your builder has installed one so tbh they have gone over the spec required. 

I would really not be pushing or changing this with the BCO as the builder has done a fair job with that - SEng has gone over spec by the looks of it and there are bigger problems on builds - doubt BCO would even notice and it’s going nowhere. 

 

[Adsibob]

7 minutes ago, PeterW said:

@Loz I don’t know the full spec but doing a quick fag packet, even with a 3.6N block and a reasonable end bearing load, a 225mm padstone is more than adequate. The key is that the beam isn’t overlapping the padstone. It’s also worth noting this is a steel with a flange so the padstone isn't required under the front flange - your builder has installed one so tbh they have gone over the spec required. 

I would really not be pushing or changing this with the BCO as the builder has done a fair job with that - SEng has gone over spec by the looks of it and there are bigger problems on builds - doubt BCO would even notice and it’s going nowhere. 

 

+1

[Loz]

Many thanks for all replies, won't bring it up and be interesting to see when BCO comes round if raises anything, by sound of things nothing to worry about, thanks for everyone taking time to reply,

 

Lawrence