Welcome Guest! The IOSH forums are a free resource to both members and non-members. Login or register to use them

Postings made by forum users are personal opinions. IOSH is not responsible for the content or accuracy of any of the information contained in forum postings. Please carefully consider any advice you receive.

Notification

Icon
Error

Options
Go to last post Go to first unread
Alfasev  
#1 Posted : 09 October 2015 11:09:35(UTC)
Rank: Super forum user
Alfasev

I am having a debate with a demolition contractor about the need of a structural survey for the whole demolition of a traditionally built masonry two storey detached house down to slab level. There is no asbestos in the building and all services have been disconnected. The house stands on a large plot, no other structures will be affected and there is no basement.

They are being advised that they need one by law but I believe that this will be disproportionate to the risks. I cannot see in this particular case how a structural survey will contribute to controlling the risks.

The demolition method is to soft strip out before progressively pulling the main structure down remotely using demolition excavators.

It would be interesting what the forum thought.
Safety Smurf  
#2 Posted : 09 October 2015 11:45:28(UTC)
Rank: Super forum user
Safety Smurf

It Might not be H&S law. it might be a planning requirement. ask them to tell you what law they have been advised under
Alfasev  
#3 Posted : 09 October 2015 12:02:53(UTC)
Rank: Super forum user
Alfasev

The planners have not asked for one and the demolition contractor simply refers to http://www.hse.gov.uk/co...tytopics/demolition.htm. There is a demolition plan & CPP in place.
Safety Smurf  
#4 Posted : 09 October 2015 12:05:29(UTC)
Rank: Super forum user
Safety Smurf

the link comes back as page does not exist.
Alfasev  
#5 Posted : 09 October 2015 12:14:35(UTC)
Rank: Super forum user
Alfasev

achrn  
#6 Posted : 09 October 2015 12:26:08(UTC)
Rank: Super forum user
achrn

Alfasev wrote:
I
They are being advised that they need one by law but I believe that this will be disproportionate to the risks. I cannot see in this particular case how a structural survey will contribute to controlling the risks.


In this particular case, if your description is accurate, and the plant is adequate (long enough reach, etc) then I possibly agree. However, part of the purpose of the survey is to validate the 'ifs'.

BS6187 'Code of practice for full and partial demolition' says various things that imply you'll always need surveys:

"5.1.2 Effective site knowledge (see Clauses 7 and 8)
"An assessment and survey of the site should be planned to identify the following, as far as possible."

This clause then talks about things like services, form of the structure etc., so you'd argue you've already done that.

"5.2.5 Avoidance of unplanned collapse: surveys

"Inspection surveys and assessments should be undertaken before work is carried out. The chosen methods of work should be such that demolition activities can be carried out in such a way that the unplanned collapse of any part is avoided by maintaining the structural stability of the remaining parts at all times. The methods of work should therefore emphasise the importance of planning surveys, including those of the structure, being undertaken before any work is carried out. The types of surveys required should be explicit and the reasons given if they relate, for example, to features which might not be immediately apparent. Such surveys may be intrusive to ensure an adequate survey of the structure is undertaken. The surveys should permit structural assessments to form a fundamental basis for maintaining adequate structural stability at all times, so the terminology and requirements should be clear to avoid any misunderstandings.

"CAUTION: The term "structural survey" can cause confusion as its meaning can differ, for example, when the term is used by estate agents where the survey is for different purposes, such as valuation."

This clause makes it quite hard to argue against a specific structural survey. However, chapter 7 (a whole chapter about 'knowledge of the site' - mostly surveys) does include the possibility that a structural survey could be a desktop study. I'd expect that to only apply when the structure has good reliable records, however.


Overall, I'd take teh view that if all that you say really is known, then the functional survey requirements have been satisfied. However, if you merely think it is true, then possibly the requirements are not satisfied. For example, do you know that you haven't got prestressed floor planks? Do you actually know that it's completely conventional construction, or are you just assuming that it is because it looks like it is?

The structural survey need not be a major undertaking - it's another of these things where it needs to be proportionate. If teh structure is as simple as reported, the proportionate survey need not be vastly costly or time-consuming.
Psycho  
#7 Posted : 09 October 2015 12:35:00(UTC)
Rank: Forum user
Psycho

As above
you have to plan for an unplanned calapse you cannot do this without a survey
In demolition only planned collapse is acceptable. An unplanned collapse of elements greater than three tonne should be reported to the HSE as a dangerous occurrence.
Ron Hunter  
#8 Posted : 09 October 2015 17:08:09(UTC)
Rank: Super forum user
Ron Hunter

Is it not reasonable for the demolition expert to assert that based on the known construction method and materials and (most importantly) on the basis of his proposed method for take-down, that a structural survey would be wholly superfluous?

This is a traditional 2-storey house - hardly a complex job!
achrn  
#9 Posted : 12 October 2015 10:25:11(UTC)
Rank: Super forum user
achrn

Ron Hunter wrote:
Is it not reasonable for the demolition expert to assert that based on the known construction method and materials and (most importantly) on the basis of his proposed method for take-down, that a structural survey would be wholly superfluous?

This is a traditional 2-storey house - hardly a complex job!


It would, if he has done a structural survey to establish that it is the known construction method and survey.

It's like risk assessments - 'do a risk assessment' doesn't necessarily mean commission a four-person team for six months (though it might). 'Do a structural survey' might well mean a simple visit by a suitable person - the demolition expert - to confirm the construction method, materials and condition of the building.

That's not demonstrating that a survey is superfluous, that's doing the survey.
Alfasev  
#10 Posted : 13 October 2015 16:04:42(UTC)
Rank: Super forum user
Alfasev

Ron is right it is not a complex job and the Client has employed competent consultants and contractors. We do have knowledge of the structure, it age, that it was extended, it highly likely to have solid as well as cavity walls, cut roof, timber floor etc. However most of this is not documented and perhaps this is the issue?
I do not believe the demolition contractor needs a structural survey to pull down this house. They have already prepared their demolition plan. I believe they are asking for it because they believe it is a compliance issue.

Do you need a structural survey that only states the obvious and what the competent demolition contractor also knows? One of the issues I have with structural surveys is that they can be full of caveats and do not tell us anything we do not already know. I am not criticising surveyors but rarely can you rip a building like this apart to fully survey it and if we set about closing all the caveats the survey costs would have been enormous.

I did read BS6187 and I know the HSE will refer to it but it is not an ACOP. Surely it has to be a risk based approach? The risk of coming across something to do with the structure that poses an additional significant risk that could have been spotted in a structural survey is low. I cannot think of anything.
achrn  
#11 Posted : 14 October 2015 11:41:01(UTC)
Rank: Super forum user
achrn

Alfasev wrote:

Do you need a structural survey that only states the obvious and what the competent demolition contractor also knows? One of the issues I have with structural surveys is that they can be full of caveats and do not tell us anything we do not already know. I am not criticising surveyors but rarely can you rip a building like this apart to fully survey it and if we set about closing all the caveats the survey costs would have been enormous.


Much of which would also apply to risk assessments or indeed method statements. Who needs a risk assessment? They only ever say what should be obvious and what competent operatives already know.

You don't want a surveyor anyway. You want your competent demolition contractor to examine the structure and confirm what you think you already know. That is the structural survey. "Survey" does not imply employment of a Surveyor, it means someone inspecting / examining the building to identify and record the things that matter.
JohnW  
#12 Posted : 14 October 2015 11:59:14(UTC)
Rank: Super forum user
JohnW

Risk assessments are good for foreseeable risks, foreseeable events and foreseeable behaviour.

We do risk assessments and get competent persons to carry out surveys as part of the written record of a plan of work, and in the event of an accident or incident we can show that we did consider the foreseeable.
boblewis  
#13 Posted : 14 October 2015 16:50:36(UTC)
Rank: Super forum user
boblewis

As a point of interest How do you guarantee that a pre 2000 property is asbestos FREE. Demolition can provide the only 100% certainty. Also any good competent demolition contractor will want to assess for themselves the safest and best options for demolition and that means a competent engineer making the final assessment and approval. If you are an expert in this why are you needing a contractor to do the work??? Remember who carries the can if something does go awry. I have had may demos where the client has stated All Services Dead and guess what!!!
Users browsing this topic
Guest
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.