Advice on who is liable

Section62

Jumblebumble said:

Doozergirl said:

Your structural engineer is far better qualified to know what is needed than building control is. 

A wall cannot be made from plasterboard.   Presumably it was a stud wall.  A stud wall can absolutely be a load bearing structural wall and even if it isn't directly load bearing, it can help control other forces that are placed on a building, as well as reduce bounce where the joists above become undersized for their new span.  

I'd take anything my structural engineer felt was needed over anything building control say!    

Hmm
I do not think you can necessarly extrapolate this from you to the OP
You may have a good well qualified structural engineer and you no doubt encountered  incompetant building control officers as I have  but you have absolutly no idea if this structural engineer is in his first week of work following qualification and if the BCO is someone who is an ex structural engineer with 20 years experience 
( why else would a structual engineer say " I dont have a clue Ask the BCO ?"
In my own profession I am not particularly well qualified but I can promise you I have encountered many people with Masters level qualifications  who do not have a clue
They know all the theory but no practical experience so the slightes deviation from what thery know flummoxes them

1st BiB - you don't become a chartered structural engineer overnight.  There is a lengthy period of training post-graduation and the need for working under supervision, before becoming chartered.  Dealing with typical domestic-type structural work will be routine to a structural engineer by the time they get to the point of chartership.  Structural engineers can also be "her" BTW.

There may well be some BCO's who are chartered structural engineers with extensive experience, but I would suggest most that followed that route into the job would have retired 20+ years ago.  The last LA I worked for had a separate structural engineering department that the BCO's would consult if there were any structural queries - since employing chartered SE's in a BCO role was then prohibitively expensive.

2nd BiB - has anyone said that?  There's a difference between not knowing/not having a clue, and suggesting asking a BCO what they would accept in a specific situation.

Bendy_House

No-one is questioning what you are saying in general, S62 et al; SEs are well qualified folk and are the source of guidance and calcs for structural matters. BCOs will not (usually) comment on whether the structural plan is adequate for the circumstance, but will only confirm whether it has been carried out to the stated specs. That is the 'norm'. Amongst this 'norm' you will have very experienced BCOs who are capable of speculating accurately on such issues (tho' they usually won't as it's not part of their remit), and SEs who can be prone to making some pretty basic errors.

So, I will bring you back to what we were told by the OP about this SE in this instance:

"When he did the site visit we did challenge why we needed a steel for where the partition wall was as it was made of plasterboard, was hollow and this wasn’t load bearing. But he was adamant that it was supporting the roof rafters.
We proceeded as advised and purchased 3 steels. Come the day of knocking down the wall, it was pretty apparent that the rafters were not resting on the partition wall and thus unlikely to need the support of the steel. So again we queried with our structural engineer why we needed the 3rd steel placed where the partition wall was. The reason we challenged in the first place was because having the 3rd steel would have also reduced the ceiling height. He wasn’t sure and thus asked us to confirm with building control if it was needed, to which he confirmed it wasn’t required.
Hope that all made sense. My question is, as the structural engineer clearly got his plans wrong despite us challenging on the day of the site visit..."

Section62

Bendy_House said:

No-one is questioning what you are saying in general, S62 et al; SEs are well qualified folk and are the source of guidance and calcs for structural matters. BCOs will not (usually) comment on whether the structural plan is adequate for the circumstance, but will only confirm whether it has been carried out to the stated specs. That is the 'norm'. Amongst this 'norm' you will have very experienced BCOs who are capable of speculating accurately on such issues (tho' they usually won't as it's not part of their remit), and SEs who can be prone to making some pretty basic errors.

So, I will bring you back to what we were told by the OP about this SE in this instance:

"When he did the site visit we did challenge why we needed a steel for where the partition wall was as it was made of plasterboard, was hollow and this wasn’t load bearing. But he was adamant that it was supporting the roof rafters.
We proceeded as advised and purchased 3 steels. Come the day of knocking down the wall, it was pretty apparent that the rafters were not resting on the partition wall and thus unlikely to need the support of the steel. So again we queried with our structural engineer why we needed the 3rd steel placed where the partition wall was. The reason we challenged in the first place was because having the 3rd steel would have also reduced the ceiling height. He wasn’t sure and thus asked us to confirm with building control if it was needed, to which he confirmed it wasn’t required.
Hope that all made sense. My question is, as the structural engineer clearly got his plans wrong despite us challenging on the day of the site visit..."

I think this^ is why DoozerGirl referred back to the tiling thread.

In structural engineering (like tiling) there can be more than one way to do a job.  The only "wrong" solution is one which is inadequate.  To "clearly g[e]t his plans wrong" would mean missing out a vital structural element, not by unnecessarily (in the opinion of others) including one.

Take a different example... removing a first floor chimney breast requires supporting the stack above. You could do it by inserting steel beam(s), or with gallows brackets, or by corbelling.  None of those is "wrong", they are all valid as structural solutions in principle.

A SE knowing what is usually acceptable to BC, and with an idea of what is cheapest/easiest to construct, may well design up an arrangement of steel beams as the best option.  The client then passes the drawings to their builder who says you don't need the beams, and instead they can use gallows brackets.  The client goes back to the SE telling them the beams are unnecessary as gallows brackets would do just fine.  The SE says they aren't sure, confirm with the BCO.  The builder asks his mate in BC who confirms in this case gallows brackets would be acceptable.

Did the structural engineer clearly g[e]t his plans wrong?  Or was the client just lucky that they lived in an area where the BC department is more flexible and the individual BCO was amenable to the builder's suggestion?

Like the tiler, without seeing everything the SE saw (and didn't see) we cannot definitively say that they were "wrong".  We'd need to ask them why they made the decision they did - what was their full reasoning.  Bearing in mind they may not have explained the full reasoning to a lay client, only the bits they thought the client would understand.

Also, the question I'd be asking now is why the rafters weren't resting on the partition wall.  That is possibly the single most important issue in the whole discussion, and one which has been largely overlooked.

gwynlas

It is indeed a stud wall - thanks for the correction, the world of renovation is very new to me. It was a timber frame with lathe and plaster. 

Interesting - I didn’t realise that a stud wall could be load bearing. There was definitely nothing resting on it with regards to the joists and seems to have been out in by a previous owner as it was sat on some engineered floor rather than original floor boards. But take your point on the use for other factors.

OP I am amazed that a lathe and plaster wall was sitting on top of engineered floor as they are multiple decades apart. So you believe you have a surplus steel that you can recoup your money on. Better that than than a structural collapse where somebody had tried to save money.

stuart45

You need to see the plans and photos of the works in progress for a better idea. The OP originally thought a stud wall (plasterboard), couldn't be load bearing. Then it's a lath and plaster wall. That suggests it's an old wall, but it was said to be built on top of a newer engineered floor.
Do they mean ceiling joists rather than rafters bearing on the wall?
The information given is a bit confusing.

Bendy_House

Section62 said:

I think this^ is why DoozerGirl referred back to the tiling thread.

In structural engineering (like tiling) there can be more than one way to do a job.  The only "wrong" solution is one which is inadequate.  To "clearly g[e]t his plans wrong" would mean missing out a vital structural element, not by unnecessarily (in the opinion of others) including one.

Take a different example... removing a first floor chimney breast requires supporting the stack above. You could do it by inserting steel beam(s), or with gallows brackets, or by corbelling.  None of those is "wrong", they are all valid as structural solutions in principle.

A SE knowing what is usually acceptable to BC, and with an idea of what is cheapest/easiest to construct, may well design up an arrangement of steel beams as the best option.  The client then passes the drawings to their builder who says you don't need the beams, and instead they can use gallows brackets.  The client goes back to the SE telling them the beams are unnecessary as gallows brackets would do just fine.  The SE says they aren't sure, confirm with the BCO.  The builder asks his mate in BC who confirms in this case gallows brackets would be acceptable.

Did the structural engineer clearly g[e]t his plans wrong?  Or was the client just lucky that they lived in an area where the BC department is more flexible and the individual BCO was amenable to the builder's suggestion?

Like the tiler, without seeing everything the SE saw (and didn't see) we cannot definitively say that they were "wrong".  We'd need to ask them why they made the decision they did - what was their full reasoning.  Bearing in mind they may not have explained the full reasoning to a lay client, only the bits they thought the client would understand.

Also, the question I'd be asking now is why the rafters weren't resting on the partition wall.  That is possibly the single most important issue in the whole discussion, and one which has been largely overlooked.

If my tiler had laid out that floor the way that OP's did - very visibly squint in all 4 directions - I'd be well pee'd off. With justification. At the very least I'd expect them to discuss the options with me first.

If my SE presumed a stud wall was supporting joists so deffo would require a steel that would not only cost me extra £100's but also lower my ceiling height, and - even when asked "are you sure?" - did not carry out the pretty basic check that would have confirmed the matter, and was then found out to have been wrong, then I'd be well pee'd off again.

And I don't think I'm unreasonable for saying that.

Never mind 'pro this' and 'pro that', or who is 'wrong' or not, this is about THIS particular case, and the information provided to us.

And I certainly have no axe to grind about these qualified folk in general - both my SE and BCO have been superb.

Doozergirl

Can we address this 'lowering ceiling height' if we're going to continuously to refer to it.  

The ceiling height is lowered only where the joist sits, you know, like a joist that is supporting where a wall has been removed and features in millions of homes up and down this country.  It's not a compromise for most people or something to be upset or complain about if it happens.  It's normal.   

It rarely, if ever impinges upon anyone's enjoyment because the steels are designed on a project by project basis not to.  The average ceiling height is 2.4m - enough to accommodate a steel underneath in the average home.  

No one needs to reduce the entire ceiling height to deal with it.  It's not a thing.  

Section62

Bendy_House said:

If my SE presumed a stud wall was supporting joists so deffo would require a steel that would not only cost me extra £100's but also lower my ceiling height, and - even when asked "are you sure?" - did not carry out the pretty basic check that would have confirmed the matter, and was then found out to have been wrong, then I'd be well pee'd off again.

This is the point.  You think it is a "pretty basic check" (not sure what you have in mind as this check) but a SE will be thinking about all the other factors which are involved in structural engineering.  It is not just about whether rafters/joists/purlins etc are 'resting' on a wall.  "Loadbearing" is a complex subject, which is what all the people with some expertise in the subject are saying in this thread.

I can well imagine that a SE who has just been told by a client that a wall can't be loadbearing because it is made of plasterboard and sounds hollow, isn't then going to spend a great amount of time explaining the principles of structural engineering and the different ways the wall can indeed still be loadbearing.  They will give their professional opinion and leave it at that.

If the SE is at fault then it relates to them not then explaining to the client that the flat ceiling could potentially be achieved if the client is willing to adopt an 'at any cost' solution.  I.e. paying the SE to do a far more thorough investigation and analysis, and design a solution where the support (if needed) is above ceiling level.

However, the work involved in doing the more thorough investigation and analysis is not cheap. You could be looking at a bill of thousands, compared to hundreds for the stell.  A lot of domestic work is over engineered precisely because it is far cheaper to put in an extra beam, or oversized members, than it is to spend professional time doing the analysis.  If the client insists they want it done a particular way - and are willing to pay the cost - then the SE should have done that.

Again, like with the tiling, the problem here is one of communication.  Not necessarily professional competence.

Never mind 'pro this' and 'pro that', or who is 'wrong' or not, this is about THIS particular case, and the information provided to us.

Totally.  And the simple fact is there is not enough information to advise "who is liable".

stuart45

Non load bearing walls can start to take loads over time. Upper floor partitions are an example in the centre of trussed rafters taking a large span, or under sized joists sitting on a wall. Removal won't normally cause the floor to collapse, but the rafters or joists may deflect and cause ceiling cracks.

Bendy_House

Doozergirl said:

Can we address this 'lowering ceiling height' if we're going to continuously to refer to it.  

The ceiling height is lowered only where the joist sits, you know, like a joist that is supporting where a wall has been removed and features in millions of homes up and down this country.  It's not a compromise for most people or something to be upset or complain about if it happens.  It's normal.   

It rarely, if ever impinges upon anyone's enjoyment because the steels are designed on a project by project basis not to.  The average ceiling height is 2.4m - enough to accommodate a steel underneath in the average home.  

No one needs to reduce the entire ceiling height to deal with it.  It's not a thing.  

(a) I'm going by what the OP has said, and (b) even an unnecessary boxed-in beam is 'ok', 'cos an SE didn't carry out a basic check?

Whatevs.