Building regs vs structural drawings

[masamune]

I have a rear extension in the plans with prior notification PD lodged with the LA. I posted a couple of questions before but I am a little confused about the scope/content of building regs drawings.

The engineer split his service in two parts from the start, structural and building regs were at £2k, around £1k for each part. A number of quotations I got before were around this range and less but they combined structural and building regs service. I also understand that building regs involve the engineer following through with the notices prior to the work commencing.

I received a set of structural drawings with calcs and materials for foundations, walls, roof structure, beams, lintels etc and now waiting for the application to go through before starting building regs drawings. I used the structural drawings for party wall notices to the neighbours and also to start getting quotations from builders. Although I was told that building regs are needed for quotations most builders said they were happy to quote from structural and brief of the work.

From what I understand building regs include more details about electrical, plumbing, drainage, build spec for lintels, build over for the drain etc to comply with building regs and get certification. However I don't understand how I can possibly decide on every single aspect of the electrics or plumbing before starting the work? How detailed do the drawings have to be?

And last, can I assign the building regs drawings/submission to another engineer if I wanted to or would that complicate things e.g they would have to re-survey the site or redo the structural drawings?

 

[tony1851]

Has your engineer told you that you don't actually need plans for Building Regulation?. You can use the Building Notice procedure, whereby the inspector just checks the work as it goes along.
Electrics and small-bore plumbing is not normally shown on drawings for Building Regs.
This business is not as complex as you seem to believe - or have been told.

 

[^woody^]

I wonder why you had a structural engineer design (and charge) for all that structural design work? The only thing that you might need an engineer for is the beam, and then not always.

For the building regs, apart from the drawing, you need a specification which describes the materials to be used and required standards for the work. This is relatively basic, and will state for instance that electric cable should be installed to a certain standard, but it won't say what type of plug sockets or ceiling lights to fit. Likewise it will state the diameter of waste pipe, but not the bathroom suite or kitchen make or style on the end of this pipe. Likewise for heating, windows, doors, flooring, decorating ......

It sounds to me like you need a specification for the work to give to your builders for quotes. And this specification will detail everything.

 

[masamune]

Has your engineer told you that you don't actually need plans for Building Regulation?. You can use the Building Notice procedure, whereby the inspector just checks the work as it goes along.
Electrics and small-bore plumbing is not normally shown on drawings for Building Regs.
This business is not as complex as you seem to believe - or have been told.

Thanks for the replies!

Sure, I am not saying it's something too complex for a standard extension. Just need to understand the correct way forward for proper certification and to keep costs reasonable.

I have read about the Building Notice, this was actually the main reason for my post. The question is whether it would be better to have drawings with spec for the notifiable work and the contractor to follow. Or say an experienced builder would know where to start from and put things right as and when the BCO instructs them during the stages?
But I read this method may be more expensive and the builder needs to be pretty up to date with regs.

The engineer's quote for b.regs was: "to produce plans, section, elevation and notes for B.Regs application and Contractor. To liaise with Building Control on queries, produce drawings showing electrical layout, drainage, build over application (if required) and general plumbing".

I have only done a simple application for a load bearing wall in the past (with plans from a structural engineer). I imagine something similar at a larger scale but certainly not something I would pick up myself so as not to cock it up

 

[masamune]

I wonder why you had a structural engineer design (and charge) for all that structural design work? The only thing that you might need an engineer for is the beam, and then not always.

I thought that when structural work is involved you need a structural engineer. It includes about 4-5 pages of calculations and specification for load bearing beams, blockwork, timber joists, foundation and the overall pitch roof structure (except from the tiles).

For the building regs, apart from the drawing, you need a specification which describes the materials to be used and required standards for the work. This is relatively basic, and will state for instance that electric cable should be installed to a certain standard, but it won't say what type of plug sockets or ceiling lights to fit. Likewise it will state the diameter of waste pipe, but not the bathroom suite or kitchen make or style on the end of this pipe. Likewise for heating, windows, doors, flooring, decorating ......

It sounds to me like you need a specification for the work to give to your builders for quotes. And this specification will detail everything.

It includes most of the materials in the structural work he has given me but not as you said the wiring, drains etc.
So from what I understand you are suggesting that it would be better to have drawings with specs for the LABC/contractor, as they can be requested for some details before or during the works?

 

[^woody^]

Normally, someone suitable draws up the plans for planning and building regs. They design something that will pass planning constraints first (even if it's permitted development), and then design the technical aspects to meet building regulations and [hopefully] practicalities of building, and building economically.

As part of that design, if something is outside of their competence, then they might engage a structural engineer to do specialist design. This is the exception, not the rule, as in the majority of cases an engineer is simply not needed. There are standard tables for most building components, so calculation is not required, nor asked for by building control.

The problem with using an engineer to do the design work is that you pay engineers fees for the whole lot, and not just for any necessary items. Also, most engineers have limited design skills (such as asthetics and use of space etc) so design wise, things can look a bit sterile. And their expertise can be limited - unless part of a multidisciplinary office.

The spec for a building regs application is very limited. Some builders will have good input into what you what to achieve, and others not so good.

A fully detailed specification will guarantee that you get what you are paying for.

 

[masamune]

Normally, someone suitable draws up the plans for planning and building regs. They design something that will pass planning constraints first (even if it's permitted development), and then design the technical aspects to meet building regulations and [hopefully] practicalities of building, and building economically. As part of that design, if something is outside of their competence, then they might engage a structural engineer to do specialist design. This is the exception, not the rule, as in the majority of cases an engineer is simply not needed. There are standard tables for most building components, so calculation is not required, nor asked for by building control.

The problem with using an engineer to do the design work is that you pay engineers fees for the whole lot, and not just for any necessary items. Also, most engineers have limited design skills (such as asthetics and use of space etc) so design wise, things can look a bit sterile. And their expertise can be limited - unless part of a multidisciplinary office.

Thanks, this is all good information!

I think my experience is very close to what you described but all the quotations I received from architects included a structural engineer fee as a standard. In my case I ended up with an engineer trying to be an architect, which you metnioned on another post. The design is simple but it lacked aesthetic input when needed and I had to compensate with my own input to have a design I was happy with. In terms of fees for this part it was pretty much the same with the architects quotes I received.

For the structural work, most builders and architects suggested the requirement of an engineer. So I had no clue of standards for the structural work. With limited experience and understanding on all the aspects of the work, I assumed a structural engineer was a must.

The spec for a building regs application is very limited. Some builders will have good input into what you what to achieve, and others not so good.

A fully detailed specification will guarantee that you get what you are paying for.

So if I understand correctly you recommend a full detail spec for the next part to be provided by the engineer, not just compliance for LABC requirements. I have seen some examples of his work that included detailed notes and drawings from tiles, to gutters, brickwork, plumbing, electrical wiring etc. Would that be the sort of thing you are talking about?