Justification for steel beam on half brick wall

[Dave 123]

We recently started our loft conversion in a terraced house. The contractor followed the plans based on a calculation that was provided by a structural engineer.

The work progressed to a level that three steam beams were put in place and by this time we heard back from the council building control department that the drawing are not sufficient and they asked the structural engineer to justify the calculation, specifically for the load of the steel beam resting on a half brick wall (only one wall, the other is a single brick wall). Our structural engineer calculated and concluded that theoretical this cannot be justified. They suggested to put fundation below ground floor level and posts through ground floor and first floor to support each beam. Another option would be to put a beam from the front to back of the house to support the three steel beams. However,the way our house is designed this wouldn't really work. The post of the first beam would end up in the middle of our porch that we share with a neighbour. Also we live in a conservation area so can't really mess with the way our house looks from the outside.

What really annoys me is that all our neighborhood ( at least 500 houses) has our type of structure (half brick between one of the neighbours) and around 1/3 of the house did their loft. Of this probably around 1/3 did it by applying for planing permission and then building control. I have spoken with 5 neighbours and they did exactly as we did but no-one asked them to justify the additional load on a single skin wall. Unfortunatel,y our BC is the local authority and I suspect that theirs was private.

Could anyone give us advice on what are our options? Can we argue that since other projects in the area were officially signed off by BC that they could possibly relax their approach to our project? Or maybe it is ok to insert a steel beam on a single brick wall and there is a way to justify it? Could we ask BC to review previous projects that were approved and offer us advice on what can be done?

I know there are things we could have done differently, but we are in the situation that we are and we need to move forward. I'll be grateful for any advice

 

[^woody^]

The contractor followed the plans based on a calculation that was provided by a structural engineer

Are you and the council saying that this engineers calculation is wrong? Is he a proper engineer, gone to college, joined the club etc ... and has PI insurance to cover his mistakes?

As for "Our structural engineer calculated and concluded that theoretical this cannot be justified". Is that a different engineer, again with qualifications and stuff?

And no you can't say "the neighbours have done it that way, so I want to"

Btw, what exactly can't be justified?

 

[oldbutnotdead]

So are you saying that you had drawings and calcs prepared by a structural engineer, these were submitted to Building Control, BC came back and said 'we don't like this, can you explain it' so your SE redid the sums and found out the numbers didn't add up so you have to heavily modify your scheme?

If that is the case then your SE is on the hook for whatever modifications are required to enable your scheme to go ahead. If he is a real SE with (as woody pointed out) real qualifications and real PI cover then his insurance carrier is in for a bad day. Yes it is possible to sit steels on half brick walls (I'm sitting underneath one at the moment) but only if a structural engineeer says it is possible- if his calcs have now said no then that's it.

Building Control can advise but usually on smaller items not major structural issues (they rely on structural engineers for that). Your road forward is to get your SE to admit that he has cocked up massively and now needs to prepare a design that will not impact on your neighbours or the external appearance of the property and will permit completion of your project such that it is safe from future collapse. This may involve legal action.

Of course, the landscape changes massively if (for example) the original drawings/calcs were done by a mate without proper instruction/invoice (or possibly prepared by one of these online outfits) and the new calcs have been prepared by someone who actually came and looked at the place with a tape measure. In that case you may be stuffed......do please share

 

[Dave 123]

The engineer works with the architect, so we never really spoke with him. Everything is through the architect. The source of the problem is with the architect not realising that there is a half brick between us and the neighbours. Although it is very obvious; you can see the brickwork from outside. Also, even if he knew there is a single skin I don't think the structural engineer would have done it differently. When the issue was presented us by BC the structural engineer said they did not know how to justify it and then they came up with the solution of posts supporting each steel. I don't think we can make any claims, I am sure somewhere is T&C they cover their backs to say you shouldn't start work before things are approved. We went down the building notice route because we already opened the roof, and that's why we also couldn't go with the private BC.

Yes, it was a different structural engineer. Our contractor suggested him as he worked on a similar project so we thought he could help us. The thing is , the skin wall was never questioned on those other projects. I believe he is qualified, this is what his signature says: B (Hons) C.Eng MICE MCABE

Theoretical justification of additional load on the single brick wall. So the BC told us that since
one of the party walls is 100mm thick we
need to provide the justification of the wall and its existing footing under new total
loadings.

 

[Notch7]

The engineer works with the architect, so we never really spoke with him. Everything is through the architect

It sounds like the architect engaged the SE, then added the structural detail to the building regs drawings.
So Im guessing the 1st SE never did a site visit.

It is unfortunate for you because had you submitted building regs drawings, if they had not passed, it wouldve gone back to the architect to sort out.
Now youve been left in a bit of a mess.

If you are lucky Tony might respond and shed some light on it.......

 

[^woody^]

Let's wait for Tony to get up. He's having a bit of a lie - in after clubbing at the hacienda.

 

[Dave 123]

So are you saying that you had drawings and calcs prepared by a structural engineer, these were submitted to Building Control, BC came back and said 'we don't like this, can you explain

Not exactly, we submitted our drawings and calculations, but the drawings incorrect indicated that there was a single brick. Our application was validated. We had a BC inspection and this is when he noted the half brick issue. By then we already installed 3 steel beams.

 

[Dave 123]

the landscape changes massively if (for example) the original drawings/calcs were done by a mate without proper instruction/invoice

I really hope this is not the case

 

[^woody^]

What is the actual issue with this "single brick"wall?

Load bearing, stability, what?

A beam can sit on 4" with no problem.

 

[Dave 123]

guessing the 1st SE never did a site visit.

Yes, to make it worse, even the architect who did the drawings never visited the site, only send his assistant to measure the house. Which I don't think it's a big deal if he did a good and thorough job

 

[Dave 123]

What is the actual issue with this "single brick"wall?

Load bearing, stability, what?

A beam can sit on 4" with no problem.

I have no idea, I hope someone will tell me that it's not an issue and explain how we can prove it. Is it because of the hight i.e. because we are inserting the steel at the loft level which has impact on stability?

Our contractor completed two jobs recently which had the same problem except that this wasn't a problem and BC said nothing. I know that every house is different. Still, I know in our neighborhood, where houses are almost the same, people did lofts and this never came up.

 

[oldbutnotdead]

Yes, to make it worse, even the architect who did the drawings never visited the site, only send his assistant to measure the house. Which I don't think it's a big deal if he did a good and thorough job

Well there's the first problem, if the assistant had done a good and thorough job he/she would have drawn that party wall as half brick. Easy mistake to make but they're paid the big bucks not to make mistakes like that.
This sounds as if it is going to get expensive- if it all gets nasty you have a decent case against the architect for negligence.
Half brick walls can sustain significant loads but depends on what they're built on, how they are buttressed, what other loads are on. (The SE who measured up for my beam here put on the calcs 'do not reroof with concrete tiles).

Out of interest, are there or were there any chimney breasts on the party wall (they act as buttresses and significantly effect the wall stability and load capacity)

 

[Dave 123]

Out of interest, are there or were there any chimney breasts on the party wall (they act as buttresses and significantly effect the wall stability and load capacity)

Chimney breast is another story, but this is not on the half brick wall.

 

[oldbutnotdead]

Chimney breast is another story, but this is not on the half brick wall.

Oh dear, sounds like another bit of the job not quite panning out.
The wall sketch- not Building Control's fault, your original architect/SE combo have cocked up. They need to be redesigning and paying for implementation of a workable scheme.

 

[Dave 123]

Half brick walls can sustain significant loads but depends on what they're built on, how they are buttressed, what other loads are on.

This is an old house build in 1913, so I am not sure if the foundation would be sufficient. Please tell me more about it, do we need to open the floor and examin foundation? What would BC ideally like to ses? You mentioned costs, why would it be expensive?