Changes to elements not on original BC Notice

[fuziduck]

I’m after some advice.

 

I currently have a Local Authority Building Notice in to move a bathroom upstairs and carry out some internal structural alterations to remove a load bearing wall.

 

When I started this work I did not intend to do too much else to the rest of the house, however that has now changed. After stripping back the wallpaper I’ve found much of the lath & plaster to be in poor condition, so much so that I have stripped it off of the external walls and removed the laths entirely. (Building is not listed).

 

Now that I have taken the rooms back to their shell it makes sense to upgrade the external thermal elements with replacement / new insulation, which is of a breathable design, however may not meet the BC new U Value targets as I am limited by the space I can lose in the rooms.

 

My question is, I have not listed this work in my Building Control notice because at the time I had no intention of doing this work.

As I want to progress this works asap I have started to reinstate the insulation ready for plastering.

When BC come out to inspect the other structural works, are they likely to pick up on this, and will it cause a problem as they may consider that I am thermally changing the external walls and insist that I hit the renovation U Value targets?

 

Any advice gratefully received.

[Temp]

They might well pick up on this unless its well covered up ?

 

See.. https://www.labc.co.uk/news/when-do-i-need-building-regulations-approval-renovating-thermal-element

 

Im not quite sure how they define "more than 50%". I think you need to comply if more than 50% of _a_ wall or 25% of all walls are being changed.

Edited April 29, 2021 by Temp

[George]

" will it cause a problem as they may consider that I am thermally changing the external walls and insist that I hit the renovation U Value targets? "

 

There are two main get outs for lower u-values (can't remember the references)

 

Most importantly is that the insulation shouldn't degrade the structure. So for an old solid wall house, a breathable insulation is suitable and you don't want too low a u-value because it will move the dew point much further inside. However.... they may want some sort of evidence (I got emails from the supplier).

 

Second get out is 15 year pay back is needed. However this is a bit tricky to justify if you are putting insulation on the wall.

 

That said... I didn't tell BC. Just got them to approve the extension works.