Is Building Control really required, small insulation task?

[Neverfinished]

Hi all,

I'd like to ask a 'general' question about adding internal insulation to ONLY the 2 external-facing walls of a bedroom in my victorian terrace, with regard to what Building Control are likely to require of me, etc.

These 2 walls amount to precisely 49.1% of the total 4-walls area of the room. I read somewhere that if an upgrade is below 50% then B.C.don't need to be involved, and thus I wouldn't need to meet U-value requirements etc!

Or, do things need to be looked at more holistically & the whole room taken into consideration - for instance - the ceiling was, some years ago re- boarded (but not yet skimmed!) so would B.C. add this in as part of my upgrade (& thus becomes >50%)? I've no plan to add more insulation to the ceiling but there's an existing 200mm of wool atop in the loft space, brought up to Regs & without having to apply to BC !

 

Also, to ask opinions of folk on here about whether its worth all the 'faff' of obtaining B.C. consent for these smallish, almost DIY projects - For myself I'm keen to comply since, when I eventually sell (10+ yrs hence) I believe a search is made, for the sale documents, to ascertain if home improvements/works legitimately comply with Regs. But it seems to me the public commonly are quite blasé about the whole matter, + some tradesmen 'forget' to apply on behalf of client, on small jobs at least. This 'delinquent' attitude seems quite common to me. Am I right this comes back to bite the house-owner eventually?

 

Any comments much appreciated.

 

 

 

[JohnMo]

If it's not a building of historical interest (listed) and you are doing insulation internally and externally, not sure why anyone needs to be involved. Photograph everything good for future reference.

 

Only thing other than the above, if the wall is currently breathable keep it that way, so add mineral wool wood fibre etc not PIR.

13 minutes ago, Neverfinished said:

existing 200mm

I would be adding another 150mm on top of that.

[Redbeard]

'Renovation of a thermal element' is 'adding or replacing a layer'. The 50% is *of the relevant thermal element in the room you are in*, so if there are 2 external walls and you IWI them both, you have done 100%, so definitely BC approval required. Theoretically if you did 49%, 49% and 2% in separate tranches you could arguably do it 'outside the Regs'. However when questions are asked when you come to sell the purchaser or their solicitor may not understand the 'letter of the law' under which you carried out the works, and may ask for an indemnity of a Regularisation Certificate. Your walls and ceiling to unheated space would be treated separately if done at separate times, but for counting purposes the 2 external walls are 100% of the wall area and the ceiling is 100% of the ceiling area.

 

I always get BCO approval even for IWI of 1 external wall since, if and when I sell, I would want to be able to wave the completion cert in front of the person who was trying to find reasons to reduce the price.

 

200mm of wool will not reach the 0.16 U value for compliance (Edit: It might, just, if the exg 200mm was 'extra special' sheep's wool with a (lower-than-mainstream-sheep's wool) lambda of 0.035W/mK) but if it was done at a time when 200mm did 'cut the mustard' then as you are not adding a layer or replacing a layer (the pl'bd) you do not *have* to add anything. I would if I were replacing the ceiling (and of course arguably at that stage you have to stump up the £180 or whatever (may have changed since last I did one) for a Building Notice).

Edited 5 hours ago by Redbeard
Clarific'n re roof U value

[Roger440]

3 hours ago, Neverfinished said:

Hi all,

I'd like to ask a 'general' question about adding internal insulation to ONLY the 2 external-facing walls of a bedroom in my victorian terrace, with regard to what Building Control are likely to require of me, etc.

These 2 walls amount to precisely 49.1% of the total 4-walls area of the room. I read somewhere that if an upgrade is below 50% then B.C.don't need to be involved, and thus I wouldn't need to meet U-value requirements etc!

Or, do things need to be looked at more holistically & the whole room taken into consideration - for instance - the ceiling was, some years ago re- boarded (but not yet skimmed!) so would B.C. add this in as part of my upgrade (& thus becomes >50%)? I've no plan to add more insulation to the ceiling but there's an existing 200mm of wool atop in the loft space, brought up to Regs & without having to apply to BC !

 

Also, to ask opinions of folk on here about whether its worth all the 'faff' of obtaining B.C. consent for these smallish, almost DIY projects - For myself I'm keen to comply since, when I eventually sell (10+ yrs hence) I believe a search is made, for the sale documents, to ascertain if home improvements/works legitimately comply with Regs. But it seems to me the public commonly are quite blasé about the whole matter, + some tradesmen 'forget' to apply on behalf of client, on small jobs at least. This 'delinquent' attitude seems quite common to me. Am I right this comes back to bite the house-owner eventually?

 

Any comments much appreciated.

 

 

 

 

Or you could not bother and just crack on and fit the insulation.

 

How will anyone ever know?

 

As always, aside from cost, what will the BCO add to this simple excercise? Bear in mind, they may not agree with your proposal and you may need to do more/something different to comply. Once they know work is happening, they know. You cannot have them "unknow".