External Insulation Without Building Regs

alwaysquestioning

I'm in the process of buying a flat (share of freehold, 2 flats in total), and the seller recently did an extension. For that, there’s a building regulation certificate, so all good.

However, after completing the extension, he added external wall insulation (EWI). For this, there’s no building regulation certificate.

A few concerns:

• Insulation Thickness: The materials he used state that for compliance, he should have added 110-120mm, but he only added 50mm. Looking at the BBA certificate for the K System M EWI -> https://s3.eu-west-1.amazonaws.com/k-systems.s3-assets.com/KSystemsM-Dash-BBA-18-5570.pdf According to the table on page 10, at least 110-120mm is required to hit the 0.30 Wm²/K requirement set out by building regulations.
  
  
• No Warranty: I asked about a warranty (as I’ve seen these typically come with 10-25 years of coverage), but he said there isn’t one. So potential red flag.
  
  
• Performance & Value: My offer was based on the assumption that the property had a brand-new, high-standard insulation. Since it doesn’t meet the designated thickness, it won’t perform as expected.

I could ask for an indemnity policy, but this only covers legal issues, not the actual quality of work or future complications.

I’d really appreciate advice on:

1. Legal implications: If the insulation doesn’t meet building regs and I don't have a building regs certificate, what does this mean for me legally?
   
   
2. Resale & Insurance: Could this cause issues when I sell the property or when dealing with home insurance?
   
   
3. Other Risks: Are there other potential problems I should consider?

The Level 3 survey flagged this as something to check, but nothing more.

from my understanding, the routes seem to be:

1. dismiss the concern - potentially struggle to sell unless I can get retrospective certificate, and low chance of expensive remediation.
   
   
2. ask the seller to seek retrospective certificate for the work - they may say sod off, it alerts the council making a potential non-problem a big one
   
   
3. Lower my offer – since the insulation isn’t up to standard and won’t perform as expected, the property isn’t worth as much as I initially thought.
   
   
4. Other routes: Are there other potential route I should consider?

Any advice would be greatly appreciated, as I’m really looking for some direction here.

user1977

alwaysquestioning said:

I'm in the process of buying a flat (share of freehold, 2 flats in total), and the seller recently did an extension. For that, there’s a building regulation certificate, so all good.

However, after completing the extension, he added external wall insulation (EWI). For this, there’s no building regulation certificate.

If it already complied with building regulations (including the standard of insulation) then surely any additional insulation is a bonus?