Cavity Wall Insulation & Flaws in The Legal Argument Against it

Discussing a Recent Court Decision on CWI Installation

I recently completed an expert witness case in Morecambe that had ran for around two years, and in fact claimant and defendant settled out of court, and I do not know what settlement was reached. Interestingly, both experts agreed in their joint statement that the cavity wall insulation should never have been installed due to pre-existing building defects, such as a bridged DPC and a defective external render system. Where we differed was in respect of the claimed consequential damage and quantum for repair costs. I assessed damages as being purely in respect of the CWI installation itself and assessed this reinstatement costs at circa £7500.00, whilst the claimants experts assessed damages at circa £32000.00 on the basis that there was significant internal damage allegedly caused by the CWI installation; this was despite not providing a shred of evidence in support of this claim.

Flaws in the Argument

The claimants expert made a number of flawed and illogical claims which I challenged him on, and to this date am yet to receive any logical response; in fact many questions were side tracked and I received the same answer multiple times, “The CWI should never have been installed.” As though this fact alone substantiated his inflated and unproven claim for consequential damages.

I recently came across a written judgement by HHJ Saffman, in relation to a failed claim against a cavity wall insulation installer. In written judgment handed down on 18th January 2021, the Claimant’s expert evidence was described by HHJ
Saffman as being “unimpressive”, and “troubling”’ He further stated, “In this case I have to say that I did not find Mr Hodgson to be an impressive witness. I have recorded at length from paragraph 70 to 129 above his oral evidence. In my view, that section of this judgment only has to be reread to identify the areas where Mr Hodgson’s evidence was troubling.”

Having read an overview of the court ruling I also found Mr. Hodgson’s evidence equally troubling and drew a significant number of parallels from my own recent case in Morecambe, where the claimants expert drew similar false conclusions to those of Mr. Hodgson. I’ll now discuss those errors and why the Judgement by HHJ Saffman sets some quite significant precedents on the quality of evidence that is submitted to the courts.

The Flawed Evidence & Flawed Logic

False Claim Number 1 (We can diagnose with a moisture meter)

Mr. Hodgson claimed that the cavity wall insulation had allowed moisture to transfer across the wall cavity, where it allegedly caused dampness on the inner walls. The expert on my recent case in Morecambe made the same claim, and in both cases, neither expert had carried out any moisture testing to prove this point. As it transpires, Mr. Hodgson only used his moisture meter in scan mode, claiming that “search mode was reliable.” Judge Saffman only had to read the manufacturers instructions on this particular moisture meter to prove that was not the case.

Calcium carbide testing
No moisture at depth despite opposing expert claiming that CWI was transferring moisture across the wall cavity

Similarly, on my case, the claimants expert did nothing nothing more than use his moisture meter in pin mode, or scan mode, and cited these inconclusive readings as ‘real’ proof that the CWI had caused moisture to transfer across the wall cavity. My own extensive moisture testing throughout the property, using calcium carbide, proved this was not the case. There were two isolated areas of wall base damp, both which were clearly proven as being caused by pre-existing defects. In simple terms, if you want to claim that CWI has caused penetrating damp, then you must test for moisture at depth in the masonry, and you must understand what is in the wall cavity to the affected area. It cannot be done by using electronic moisture meters in isolation!

False Claim Number 2 (Poorly Installed CWI causes Cold Spots & Condensation)

It was then claimed by Mr. Hodgson that voids (incomplete fill) in the cavity wall insulation cause cold spots on the internal walls, which lead to condensation. He later conceded in oral evidence that it is wrong to say that all voids lead to condensation. In my own case, the claimants expert made the same claim and I specifically challenged him on this point by asking., “Please explain the mechanism or temperature dynamics, by which cavity wall insulation reduces the temperature of the wall where voids exist in the CWI? If you cannot explain this, do you agree that voids in CWI cannot cause cold spots, they can simply fail to deal with the cold spots that already existed?”  I received this response… Insulated sections of the wall will retain heat better than uninsulated void areas, which will lose heat quicker.  These areas that are uninsulated will be colder than the rest of the all hence the phrase cold spot.”

Of course, I didn’t ask him to define a cold spot, I asked as to how a void in the CWI can cause a cold spot on the internal walls, as opposed to simply not addressing a cold spot that was already there. This is a fairly significant technical point because it’s at the heart of the question as to whether a poor CWI installation can cause condensation damp within a property, as claimed by these experts, and I am of the firm opinion that it can not. The one exception to this would be where saturated CWI transferred moisture to the inner leaf of masonry, which in turn became saturated, and as a result, the moisture evaporating from that building fabric could add to internal humidity levels and further contribute to what we call ‘secondary’ condensation damp. See false claim number 1 as to how this claim can be proven.

Debris to wall cavity caused localised wall base damp
Debris to wall cavity caused localised wall base damp

False Claim Number 3 (Poorly Installed CWI Causes Mould)

Along with the false claim of condensation damp, comes the false claim that a poorly installed CWI system can cause mould. In both cases the claimants experts claimed that the properties were severely affected by mould and yet Mr. Hodgson failed to record evidence of this and was criticised by Judge Saffman on this point.

The opposing expert on my case made a similar claim and yet failed to include any evidence of this in his report. I commented that by asking “Black mould where? There is little evidence of this in your report, and proof is required in support of the quantum claim. Black mould is not ‘damage’ and it can be washed off.  There is also no evidence of decorative spoiling caused by the CWI installation. This issue is critical to formulating a quantum, and I would ask that you provide proof, rather than opinion on this issue.”

I found mould to one area, an unheated side entrance porch that was affected by wall base damp due to debris in the wall cavity and an external plumbing leak. The claim that poorly installed CWI causes either condensation damp and/or mould run parallel to one another and again, a poorly installed CWI system can simply fail to deal with pre-existing issues, it cannot cause them. Again, the single exception is where saturated CWI transfers moisture to the inner leaf of masonry, which in turn becomes saturated, and as a result, the moisture evaporating from that building fabric could add to internal humidity levels. which increases the risk for mould colonisation. See false claim number 1 as to how this claim can be proven.

False Claim Number 4 (Thermal Imaging Can Be Used as Proof for Damp in a Property)

Judge Saffman Criticised Mr. Hodgson for using thermal imaging as proof that the property was damp. Judge Saffman stated that, “Equally, I was not convinced by his evidence as to the use to which a thermal imaging camera can be put. I do not think that it could be seriously doubted that such a camera simply measures heat radiating from a surface and that in those circumstances it can only be a possible pointer to the existence of areas which may be damp but it does not detect damp itself.” The judge was 100% correct on this point because wherever you see thermal imaging as identifying a damp spot, this could simply be cold bridging or an insulation void. In those circumstances you must follow up with meaningful moisture testing.

In my own case, there was also disagreement on thermal imaging, though the opposing expert did none. The thermal imaging showed that large sections of insulation were missing from the kitchen ceiling and the claimant himself conceded that this was removed when the ceiling downlights were installed. It was another area showing where the property had pre-existing defects or in this case high levels of heat loss through the kitchen ceiling. Ironically, the opposing expert didn’t claim that this missing insulation would “cause cold spots.” In fact he commented that, “Thermal imaging can only be seen as a guide.  Access to the roof space should have been carried out to ascertain whether or not the insulation voids existed within the roof space.  Without this, the findings are conjecture.”

Missing ceiling insulation
Missing ceiling insulation but dismissed as ‘conjecture’ by Opposing Expert.

In this particular case, a claim for £203k was dismissed and the claimant was awarded nominal damages of £500 to simply reflect the fact that there were voids in the wall cavity. The use of these standard allegations against cavity wall insulation can’t continue without supporting evidence and from my perspective, it was impressive to see the obvious technical understanding and grasp that Judge Saffman had in this case and I see a number of critical legal precedents:

  1. If you want to claim that moisture has transferred across a wall cavity by way of the CWI system, then you must prove it with meaningful moisture testing. I don’t think Judge Saffman fully understood what is required (Testing for moisture at depth) but he was smart enough to dismiss relative readings taken with a hand held moisture meter.
  2. You can’t simply claim that voids in CWI cause cold spots to internal walls. There is no logical basis for this claim and Mr. Hodgson was forced to recant on that claim. Yes, voids can fail to deal with cold spots that were already there, but any mould or dampness that occurs to that area would be a pre-existing defect. The single greatest benefit of well installed CWI is that it raises internal wall surface temperatures, in the process combatting issues with cold surface condensation.
  3. As for point 2 above, if voids in CWI can’t cause cold spots, then how can they be responsible for condensation damp and mould? Judge Saffman clearly did not accept Mr. Hodgsons evidence on this point and I have outlined that the only way this can happen is if you prove that the CWI has caused moisture transfer across the wall cavity and subsequent saturation to the inner leaf of masonry. It is foolhardy to make these claims in the absence of such evidence.
  4. Judge Saffman has outlined clearly that the courts will not accept thermal imaging as proof for dampness in a property. I would add that It can only support the claim if thermal imaging is followed up with meaningful moisture testing.

2 responses to “Cavity Wall Insulation & Flaws in The Legal Argument Against it”

  1. Rosie W avatar
    Rosie W

    Thanks for taking the time to share all of this, it is useful to see how these scenarios play out in court and also reassuring that the more logical evidence was considered by the judge in this case. Can I ask what the internal symptoms were in this case and how long they have been going on for (or reported if different)? Also were there any other contributory factors i.e. as-built cold bridging?

    1. Joe Malone avatar
      Joe Malone

      Hi Rosie,

      From what I could see it was very similar to my case. Claims made of mould but with no evidence. Claims made that the property was damp due to the cavity wall insulation with no supporting evidence outside of a spurious claim that thermal imaging showed dampness in the property, which of course it can’t. I can only outline other factors in my case, not on the Saffman ruling.



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