Thanks firesafety101

Your posting raises a number of issues.

1. My understanding is that Building Control Regulations in England are similar to those in Scotland, wherein the days when the Local Authority Building Control Officer had to "approve" the design and then construction of works has long gone, to be replaced where in effect the LA accepts some paperwork to say that the design is compliant with the relevant requirements of the "Approved Documents" and has been constructed to meet the same requirements.

All of which in effect means that we already have quasi-privatised Building Control.

....largely restricting the power of the LA to being one of not agreeing to the sign off a certificates of design and/or construction and/or completion - which has very little clout until such time the lack of such documentation becomes a problem when an owner wants to sell to someone else.

2. Is the nature of this building such that if it were being constructed in the near future it would fall into the scope of the Building Safety Act and Regulations being made under BSA?

3. There is also the issue of the role of CDM Principal Designer. Under three iterations of CDM the duties on first Planning Supervisor, then CDM Co-ordinator and now PD have always been closely cross-referenced to the CDM duties on the designer(s) taking into account that the definition of this duty holder extends beyond the most obvious idea of a Designer.

There have always been loopholes in CDM, in particular as regards the scope of the designer duties when it comes to anything than protecting those carrying out construction work or future tasks by those at work.

In CDM 1994 there was also a rather clumsy definition of cleaning work to delineate some activities from day to day cleaning of a structure. CDM 2015 is a bit tighter and puts an onus on the designer (but LESS on the PD) to give adequate consideration to ANYONE at work on a structure.

Which means that suppose someone worked from home in the building to which you refer, then the CDM designer duties might come into play, and the same would apply when the designer should reasonably assume that there are parts of the building in which people will have to be at work in the future.

But there is a massive hole in CDM when it comes to considerations of whether the structure is what is often called "fit for purpose" - the residential occupiers (whom fire legislation explicitly treats as more vulnerable as they may be asleep when fire breaks out) are in effect out of the scope of the designer duties under CDM 2015.

I would note that this doesn't mean that the designers have no duty of care towards such people. That they do is implicit in both common law ("neighbour test") and via Section 3 of the Health and Safety at Work etc Act 1974.

However, if the designer understandably focuses on what CDM says they have to do, then such implicit duties may easily receive less attention.

As a parallel to your scenario consider a new road bridge.

CDM tells the designer to have adequate regard for those building the bridge, maintaining it, and anyone at work at the bridge, e.g. someone doing rope access to do a bridge inspection. 

But the most severe thing that may potentially happen at this bridge is for it to collapse when X vehicles and occupants are passing across - and the collapse is entirely outside the scope of the designer CDM duty!!