What level of detail in BC tech drawings?

[flanagaj]

I have never done or seen an example of drawings submitted to BC and as a result have no idea how much detail is involved.  For example, I am currently looking at Posi-Joists and thinking of getting a quote, but I am now thinking that the technical architect will need to provide this level of detail in his technical drawings that he will submit to BC.  The same goes for the ground floor slab makeup.  Do I need to tell him that we are planning on having the unconventional insulation / dpm / 100mm slab with the UFH tied to the steel mesh?

 

[G and J]

Our experience was this

 

Architect technician did BC drawings and yes there is a lot of detail, and yes we did input on the levels of insulation we wanted and the floor/ wall build ups and these were submitted to BC (private) and accepted to allow notification of the start of works. We also checked, checked, checked the room sizes, window placements, door sizes, stair pitch etc were still what we were expecting, rather than 'standard' by default (changes were made)

 

BUT

 

There was still a lot of the detail to be worked through ('designed by others'). For us this was delivered as follows

 

Above ground the company who were making the frame, took the architects drawings (provided direct electronically) and worked through the structural elements (steels, joists etc) to deliver that design. We again checked all of the above.

 

Below ground we employed a structural engineer to design the foundations and he also, partly because he wanted to, conducted a review of the timber frame/steels design and its structural integrity (for example a double check that there is very unlikely to be any movement in the upstairs floors (our requirement) due to no. of joists and spans specified

 

And then in practice, when the ground conditions were actually visible on the entirety of the site(there was a couple of rudimentary soakaways and a seam of soft ground in otherwise sandy soil) the SE redesigned the floor build up to deliver what was structurally needed cost effectively (materials and labour)

 

 

[nod]

As above 

Much of what the Architect submits is quite generic 

Floors Roof drainage steels etc Designed by other 
When you get your quotes for the above BC will be fine with these as they will have all the detail 

[Bonner]

I had a nightmare with eaves detailing which the architect had drawn but didn’t work with the necessary roof structure. Make sure the main structural elements are worked out before ‘signing off’ the design.

[Spinny]

Our architect did a drawing showing the drainage layout and services/extractor positions as part of detailed design. The structural engineer did a report with the joist/steel/lintel dimensions and layouts, structural calculations for them, foundation and slab specification etc. We had test pits dug to assess ground conditions.

I am not sure building control pore over it too much if they can see you have professionals on board.

 

In reality it doesn't become fixed in stone. We had two lintels changed from concrete to steel during build, and just sent the new specification and calculations for these from the structural engineer to BC.