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Building Control for re-felt and warm roof?


Subfrequenz

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Hello all!

 

I'm looking to re-felt an existing flat roof on a town house in Crawley. It hasn't been touched for a good 30 years, although it has been repaired so is leak-free.

 

I had a telephone chat with a duty surveyor for Sussex Building Control who seemed to suggest that a building control application isn't needed 

This is because the deck and below isn't being replaced, only the top felt, with additional warm roof being added on top of the existing structure. 

 

Would be good to know of anyone else's experiences! Thanks. 

 

Below is a rough outline of what we are planning. 

 

* Remove all existing roof covering to bare timber deck 
* Apply SA bitumen primer to whole of roof 
* Apply first layer of torch safe vapour control layer 
* Fix 50 mm timber kerb around whole of outside edge 
* Lay 50mm flat roof insulation boards
* Create new timber outlets to downpipes
* Apply torch on sanded underlay 
* Fix 100mm GRP drip trims to outside edge 
* Apply Technotorch mineral capsheet to finish
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9 minutes ago, Mr Punter said:

If there is no insulation in the roof you may want thicker insulation boards but this can impact on the eaves and abutments.

Cheers. Do you reckon this is exempt from building control? I appreciate if the roofer discovers major issues with the joists and boards then it will probably be needed. 

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On 24/07/2021 at 15:54, Subfrequenz said:

I had a telephone chat with a duty surveyor for Sussex Building Control who seemed to suggest that a building control application isn't needed

Get that in writing to avoid any poroblems in the future.

I'd say that because you're affecting thermal properties of the roof, that would need to be done to current standards, though the workaround can be using extra wool in the attic.

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@Subfrequenz

 

Google found.. 

https://www.nfrc.co.uk/docs/default-source/form-protected-documents/homeowners/householders-guide-to-flat-roofing-2015.pdf

 

Quote

 


PLEASE  NOTE:  Refurbishment  of  a  flat  roof  is  likely  to  be  reportable  to  the  Local  Authority  Building Control  (LABC)  and  approval  must  be  sought  unless  the  contractor  is  a  member  of  CompetentRoofer  (see page  13). Part  L  of  the  Building  Regulations  may  require  additional  thermal  insulation  to  all  re-roofing  projects where  the  roof  underneath  is  heated  e.g.  a  kitchen  or  bathroom. The  required  ‘U’-value  is  0.18W/m2K. You should  discuss  converting  to  a  warm-decked  roof  with  your  contractor  and  LABC. Here  are  some  examples... snip..
 

 

 

Page 13 says..

Quote

 


CompetentRoofer  -  the  Government-licenced  Competent  Person  Scheme, that  allows  self-certification under  the  Building  Regulations  of  roof  refurbishments  within  England  and  Wales. Works  carried  out by  CompetentRoofer  members  automatically  receive  the  Building  Compliance  Certificate  and  are warranted for a period of ten years.
 

 

 

Worth reading whole document before getting quotes.

 

The situation appears similar to that for replacement windows or notifiable electrical work eg The "competent scheme member" will notify Buioding Control for you.

 

 

Edited by Temp
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14 hours ago, Temp said:

The situation appears similar to that for replacement windows or notifiable electrical work eg The "competent scheme member" will notify Buioding Control for you

So it will reduce hassle and cost with BC application, but will not remove the need for more insulation than planned 50mm. Unless of course you find a 'competent builder' happy to issue a certificate stating that the job is ok, even if it isn't. 

 

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+1

 

If you have existing insulation between rafters and only put 50mm above them that would leave the top of the rafters close to the cold side and without ventilation = possible condensation  risk.

 

Ideally you need more above the rafters and less below or keep it as a ventilated cold roof.

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