external insulation

[russellsmiler]

Hello all here.
Hoping for some advice or interpridation of the regs....
A 1960s bungalow (not mine) is being extended the full width of the back elevation, the design as been approved by building control ect, and foundations are in ready for substructure, The remainder of the existing external wall are pebbledashed upon an uninsulated cavity brick wall...the owners wish to insulate externally to give some thermal improvement to this old house and because of the window reveals etc wish this to be max 50mm...building control are stating that if you insulate the existing bungalow externally it must meet a regulationary standard...the owners are saying they just want to improve the property and have a more uniform appearance externally.
Surely (or not) in this case the owners can do nothing and leave the bungalow uninsulated and there is no legal obligation for them to have to do any insulation, so surelky this allows them to choose a 50mm thermal layer as just an improvement and building control have no say in the matter???
Any advice please

 

[JP_]

Why not design the extension so it is wider by 10cm or so to accommodate the external insulation on the old?
I have done similar, but forgot to inform BC. I insulated internally on the sides of old, and mostly externally on the front of old.
But looking back now, I would have been better off widening the extension and insulating externally. Although it would have cost loads more due to windows, gas pipes, electric etc. etc. that might all need shifting about.

 

[russellsmiler]

thanks JP...slightly missing the question, the extension is set to be built given a true line between old and new with allowance for 50mm build up on the old...its just BC have raised an issue with the 50mm not complying, as said this to me is a homeowners choice to improve thermal values without BC poking it about....but are looking for support ofr otherwise.

 

[cdbe]

They can't sign it off as being "a bit" compliant. Would 50mm plus cavity fill be any better, or plus some internal?

I presume they're saying we can't sign off but won't take action if you just do it?

 

[mrrusty]

Do the extension, get it signed off. Later put the external insulation on the existing as a separate job. Whether you would apply for new regs application is up to you.

 

[russellsmiler]

mr rusty
we have decided thats the best approach. thanks , and thanks to all