Does Building regs trump British standards? 

 

House build limited to 3.2m ridge, architect is designing roof to 1 in 40 as he says thats the regs to allow for bad tolerances and any sag as per regs...but this dramatically lowers ceiling height.

 I would have thought that modern materials and web joists would allow a 1 in 80 design that retains 1 in 80 slope.

BS:6229 allows design and build at 1 in 80 - so Building regs or British standards?

I think your architect is designing in some tolerance for typical building site practise! Recent experience and research myself suggested design to 1 in 60 for the 1 in 80 minimum. What tends to trump both is the opinion of your BCO I reckon ?

Edited November 13, 20205 yr by SimonD

Building Regs is only one interpretation of the laws.

Not sure how much the actual BSI standards woukd cost to buy, but worth asking local library if they have access to a copy.

Edited November 13, 20205 yr by SteamyTea

BS 6229 states design fall should be 1:40 to make sure actual fall is no worse than 1:80 accounting for site tolerances & inaccuracies. There are some waterproofing systems designed for zero falls - these should have 3rd party certification and need careful design (no back falls).

Cant afford ridiculous cost of BS, but according to Axter the BS 6229 : 2018 – Flat roofs with continuously supported flexible waterproof coverings – Code of practice states zero fall roofs can be designed to 1 in 80.

I would be using EPDM.

Here's a cut& paste of the relevant clause from BS 6229:2018:

 

 

4 hours ago, gravelrash said:

Does Building regs trump British standards? 

 

I stand to be corrected, but I don't think British Standards have any authority in and of themselves; only indirectly through reference from other things (such as building regulations) that do. Furthermore, BS6229 is a 'Code of Practice' rather than a 'standard', which may be relevant. 

Edited November 13, 20205 yr by MJNewton

Where in the Building Regs or Approved Docs does it give information on min. roof falls?

Google found..

 

https://www.bauder.co.uk/technical-centre/design-considerations/flat-roof-design-considerations/falls-and-drainage#:~:text=According to BS 6229 %26 BS,along with any internal gutters.

 

Quote

It is a requirement of Building Regulation Part H that adequate provision is made for rainwater to be carried from the roof of the building. According to BS 6229 & BS 8217, flat roofs should be designed with minimum falls of 1:40 to ensure a finished fall of 1:80 can be achieved, allowing for any inaccuracies in the construction. This applies to general roof areas along with any internal gutters.

 

 

 

 

However I can't find where it says that in Part H. Part H doesn't appear to reference either BS standard.

 

Perhaps see page 38 onwards.

Edited November 13, 20205 yr by Temp