EXTERNAL WALL INSULATION: The Defects are Often Built in. Part 2

The First Visual Signs of Premature Failure Explained

Underlying Rockwool Insulation Slabs Now Visible

Underlying Rockwool Insulation Slabs Now Visible

Some time back we blogged about a Midlands high rise EWI scheme that we’d monitored and noted that defects were being built in. Interestingly we have now noted very obvious visual signs of premature wall cladding failure. In fact we recently investigated a failed EWI scheme that exhibited a number of visual problems that were also noted on this scheme. When you consider that it generally costs circa £1m to install EWI to a high rise block then system failures become extremely expensive to remedy. In this particular case I drove past the building today and immediately noted early visual signs of system failure, in particular, what we call ‘thin coat failure.’ The white finished render should be ‘in plane’ and present a smooth finish across the whole facade but in this particular case you can now see that the underlying Rockwool insulation slabs in the Alsecco system are clearly visible; so what causes this and what are the implications?

Pillowing & Mattressing

We have previously written about the effects of pillowing and mattressing but this is something generally seen in Phenolic insulation boards, it isn’t a problem you see in Rockwool slabs.  Please read http://buildingdefectanalysis.co.uk/solid-wall-insulation-ewi/a-case-of-pillowing-or-mattressing/ for more information.

Technical Issues

Since we had initially commented that insufficient hammer fixings were being installed to the Rockwool slabs then we also believe that there is risk of structural failure at the interface between the Rockwool slab and the underlying substrate. However, experience tells us that the visual evidence suggest something far simpler… The render base coat has probably been applied far too thinly.  It is a problem that we are commonly seeing and we’re unsure if this is a result of the construction bean counters short ordering materials or whether it is simply down to poor site quality management?  The problem with overly thin render coats stretches well beyond the obvious aesthetic problem and raises two key technical issues.

  1. An overly thin render coat does not have the same impact resistance.
  2. An overly thin render coat is more permeable and hence far more susceptible to penetrating damp and subsequent saturation of the underlying insulation.
Another elevation with underlying Rockwool slab insulation clearly visible.

Another elevation with underlying Rockwool slab insulation clearly visible.

Thin Coat Failure

So we believe that this system is suffering from thin coat failure and has failed prematurely on both aesthetic and technical grounds and we predict significant technical problems in the near future. The only subjective discussion is with regard to the degree of failure exhibited.

You may wonder why these thin render coat failures are not immediately obvious on works completion and we think that is down to simple curing and shrinkage of the render, which can occur over a number of months; this project was only completed in October 2015 but visual system failures had to be evident months before we observed them. As the render coat shrinks back, it thins to reveal the underlying insulation boards, usually first noticeable when sunlight hits the elevation concerned.

Solution to Failure?

So, is there a remedy for this? If caught early enough before water penetrates and saturates the insulation, is there a quick fix? Sadly no. The problem is that whilst it may seem reasonable to offer additional coats to increase the render thickness, this  system would no longer have BBA approval. The reason for this is simple… You would be applying further base coat over an existing topcoat but the system was never tested with base coat applied over topcoat and therefore would no longer be BBA approved. We have written correspondence from the BBA stating precisely that fact.

Poor installation of Rockwool slabs.

Poor installation of Rockwool slabs.

It is easier to contextualise this system failure when comparing the underlying defects noted as the system was being installed and here we can see the poorly installed rectangular insulation slabs that are now showing through the render coat.

In our opinion both Rockwool slabs and EPS boards offer greater flexibility and potential for at least partial recovery of the EWI system but even retaining the insulation needs careful consideration based on a detailed investigation and recovery of site evidence.

 

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Guarantees for Solid Wall Insulation and Getting Insurance for Failure.

More Unscrupulous Dealings from The World of External Wall Insulation

If considering EWI then accept nothing less than a 25 year guarantee. Some unscrupulous installers will not offer it.

If considering EWI then accept nothing less than a 25 year guarantee. Some unscrupulous installers will not offer it.

We have previously warned about the double standards being operated by some external wall insulation installers with regard to the guarantees being offered on these systems. DECC insisted that these systems came with a 25 year guarantee if they were to be rolled out to the mass market; enter SWIGA, the company formed to provide those guarantees. However, it seems that a large proportion of the industry is only providing those guarantees for grant funded work, such as ECO funding. If you are a cash buyer for one of these systems then there is a strong chance that you will be offered a substantially reduced guarantee. I have a client who was only offered a 12 month guarantee, though their installer later offered to pass on the system manufacturers 5 year materials guarantee, which is fairly pointless. When made aware of the 25 year SWIGA guarantee my client questioned this but found that their installer was not a member of SWIGA and therefore could not offer the 25 year guarantee. As grant funded work dries up we are seeing a number of installers sever ties with SWIGA or generally failing to maintain any links with a body that can provide the appropriate level of insurance protection. After all, if the Government isn’t forcing you to offer a 25 year guarantee then why pay membership to an organisation that oversee’s an insurance scheme that you are not offering to clients. Irrespective of whether work is privately or grant defended this application of double standards is an industry scandal. In this particular case the installer was recommended to my client by the system manufacturer, despite that installer having no way to provide the appropriate guarantee. Should we expect material suppliers to carry out some level of due diligence to ensure that their recommended installers can offer an appropriate guarantee? I think so, and if you can’t do this then don’t make recommendations!

 If you have followed this blog then you will be aware that the system failed within weeks of being applied leading to months of conflict and disagreement. One culmination of the disagreement over the guarantee being offered, or rather, not being offered, was the installers suggestion that they would now provide the following system guarantee…

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To my mind this raised a very obvious question, which is, can you actually get insurance cover for an EWI system that has already failed? Possibly… but as with all things risk related, the greater the risk, the more you pay to offset that risk. In this case we are fairly confident that the insurance company  would refuse to insure a previously failed and repaired system, or they would increase the premium to such an extent that the installer would not want to pay the price. We are fairly confident that the system failure was not disclosed to the insurer because the insurer would have wanted to know the full facts relating to the cause of failure and repair in order to help their loss adjusters reach a decision. So in fact a guarantee is being offered when the insurer is not yet in receipt of all the facts relating to the case. We’d go so far as to say that having spoken to this insurer, the policy may not actually be available under these circumstances. It goes without saying that it would be construed as fraud to obtain an insurance policy without disclosing all material and relevant facts and I’d consider substantial failure of the system within weeks of application as fairly relevant, wouldn’t you? You can pick holes in a lot of these policies until the cows come home and the fact remains that the vast majority of EWI failures are caused by poor workmanship, inadequate design or poor site storage of materials. Given that poor workmanship is the primary common cause of failure then you’re left in dispute with your contractor because a lot of these policies only pay out in those circumstances if your contractor is no longer around to deal with it. There are a lot of aftermarket guarantees and you should study them carefully if you’re placed in an unfortunate  position of having to buy one. To avoid this proverbial stable door simply ensure that your installer is registered with SWIGA and can provide the full 25 year protection; If not then find an installer who can! Oh, and please budget to have your installation independently quality managed, we guarantee that you’ll be glad you did.

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Worst EWI Installation we’ve Ever Seen

Another Warning with Regard to The Poorly Regulated EWI Industry

Just when we think we have seen the worst EWI installation we’ve ever seen another comes along to take the title. So for now, and as we write this blog, this is indeed the worst installation we’ve ever seen but we’ve learned to appreciate that it’s only a matter of time before another comes along to take the title.

We have recently been advising a client in Carmarthen with regard to the quality of their installation and with regard to a potential construction claim against the installer. This particular system is a Wetherby system, nothing wrong with that so long as it is installed to appropriate guidelines with a reasonable degree of skill and care by qualified installers.  We’ll comment more on this installation after you’ve viewed the image slider…

Negligent and Incompetent EWI Installation

Clients chose EWI due to water ingress

Clients chose EWI due to water ingress

Water ingress continued after EWI installation

Water ingress continued after EWI installation

Insulation boards wet before render applied

Insulation boards wet before render applied

No base track in some areas

No base track in some areas

Moisture blisters soon after installation

Moisture blisters soon after installation

Lead apron sealed with Gaffa tape

Lead apron sealed with Gaffa tape

Broken hammer fixing

Broken hammer fixing

EWI applied to random rubble wall. Note gaps behind boards.

EWI applied to random rubble wall. Note gaps behind boards.

Ragged edge on base track

Ragged edge on base track

Shocking installation standard

Shocking installation standard

Widespread moisture blistering

Widespread moisture blistering

More moisture blisters

More moisture blisters

Yes, this really was the finished product.

Yes, this really was the finished product.

Delamination of top coat.

Delamination of top coat.

Clear bathroom silicone seal against slate roof tiles

Clear bathroom silicone seal against slate roof tiles

Adhesive failure of silicone

Adhesive failure of silicone

Poor edge detailing with leadwork

Poor edge detailing with leadwork

Incredibly, the insulation extends to the floor and has no base rail.

Incredibly, the insulation extends to the floor and has no base rail.

Terrible detailing at door reveal.

Terrible detailing at door reveal.

More poor flashing detailing

More poor flashing detailing

Crack in render and top coat delamination

Crack in render and top coat delamination

Large moisture blister

Large moisture blister

Failure of sealant around cable

Failure of sealant around cable

Moisture blisters to right of door reveal.

Moisture blisters to right of door reveal.

Poor detailing to base of render

Poor detailing to base of render

Passive air vent not sleeved.

Passive air vent not sleeved.

This installation standard cannot be excused as a rush job or a Friday afternoon job, rather, we’re of the opinion that it must have been installed by completely unqualified site personal. In all likelihood, they were not just unqualified to install EWI but the general standard would tend to indicate that they have no previous construction experience whatsoever but nevertheless chose to jump onto the EWI gravy train.

We’ll let the quality of the work speak for itself but one thing we found particularly interesting on this installation is that a decision was taken to install EWI on a random rubble stone wall. When EWI insulation boards are applied to a wall then walls have to be regularised to ensure that a smooth, in plane surface finish is achieved at the face of the installed insulation boards. Where EPS is used then sometimes the boards are given a final rasping or sanding  to help achieve a flush, in plane surface, prior to the base coat application. If walls deviate by more than 20mm then it becomes almost impossible to regularise the walls and in fact, in our opinion EWI was completely unsuitable for application on a random rubble wall and should have been ruled out at design stage, but of course it wasn’t. Not only was it applied to a random rubble wall, it was also extended to the floor to wick up moisture; presumably due to the impossibility in applying a straight and level base rail to a random rubble wall.  The slider image shows the random rubble wall after the base of the EWI was cut away to expose the stone wall; we believe this happened after the installer heard that the system manufacturer were coming to inspect their installation. We could write a thesis on everything that is wrong with this installation but you should take this as another warning with regard to ensuring that systems are properly designed and that you have seen a written copy of the design process. You should ensure that you inspect company credentials and more importantly, the credentials of the site installers, and you should ensure that the system comes with a 25 year SWIGA guarantee; these aren’t always being offered to private buyers of these systems. Finally, if you are a private home owner paying for one of these systems then our strong advice is you you set aside a small percentage of the budget to have your installation quality managed and signed off at key stages by a Chartered building professional who understands these systems. Set up a minor works construction contract and look to agree staged payments at each successful stage of inspection. In our opinion it would be utter folly to pay for one of these installations upfront.

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How Guaranteed is My Construction Guarantee?

The Murky World of Construction Guarantees, Latent Defects & Contractual Claims
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Source: swiga.co.uk

I was prompted to write this blog after a client recently explained to me that her builder recently explained to her that in fact, he had no contractual obligation to correct her work and he was only there to prevent reputational damage.  It is fairly common for builders to make statements that their work is only guaranteed for 12 months and perhaps some of them genuinely believe this. Then on the periphery of any guarantees that are given directly by the builder there are all sorts of insurance policies and schemes that may afford the buyer further protection. The ten year NHBC build mark policy or the 25 year SWIGA guarantee for solid wall insulation systems are both examples of policies that are meant to provide the purchaser with additional peace of mind.

The SWIGA guarantee is particularly interesting and borne of the DECC’s requirement for the EWI industry to provide a 25 year guarantee before rolling out solid wall insulation to the mass market as part of Green Deal or ECO works. It is a requirement that ECO work has a 25 year guarantee. So what about homeowners who are privately funding their SWI installations? Surely they are afforded the same level of protection? Well actually no, it turns out that often they are not. A number of companies are delivering privately funded work without the benefit of the 25 year guarantee that is required for ECO funded work. Buyers may get the system suppliers 5 year guarantee on materials but are often told that the installer only guarantees work for 12 months. When it comes to solid wall insulation consumers are quite often confused by the contractual arrangements that exist between themselves, the installer, the supplier, the BBA and any other third party who may be providing the 25 year guarantee. They quite literally do not know who to turn to first when something goes wrong, particularly when they find that their installer is being unresponsive or obstructive in dealing with matters in a reasonable manner. I will focus on one case in particular because the principles could equally apply to any buyer of construction works. The buyer in this particular case bought a very expensive SWI system that failed within weeks of purchase. It was clear that the system had been poorly installed to such an extent that it would not have had BBA approval. They were then shocked to find that they did not have a SWIGA guarantee and the installer was not registered with SWIGA to install this product. Despite this fact, the installer had been heavily recommended by the system supplier. The system supplier rightly pointed out that they have no contractual relationship with the end user and that their relationship lies with the installer and even after admitting that the installation had non-standard components refused to intervene or take action with the installer for not installing a fully approved system, that in all likelihood will not now have BBA approval. If a complaint is made to SWIGA then they would generally direct the designer to carry out an investigation but in this case the installer is playing both poacher and gamekeeper and being very selective about which elements of failure are being investigated. They also refuse to answer a number of written detailed questions that have been put to them by the end user.  This can occasionally happen and perhaps potential defendants want to commit as little as possible to written record but I’m sure that the courts would see this as unreasonable behaviour.

 You should give your constructor or installer reasonable opportunity to understand the scope and nature of your claim and further opportunity to correct it and again, you may want to seek professional advice with regard to what constitutes a reasonable standard for remediation work. In this particular case, we do not feel that slapping extra base coat and topcoat over an existing silicone top coat in a system that is already exhibiting moisture blisters, is an acceptable or reasonable long term solution. Moreover, we feel sure that this ‘solution’ would not meet with BBA approval.

We are of the opinion that the installation is negligent and only complete removal and re-application of a system from scratch under heavily supervised conditions will solve this problem. In the event that the installer doesn’t agree and refuses to acknowledge the defects  then what are the options for this end user? A purchaser who now understandably wants the benefit of a 25 year year guarantee that is rolled out to the mass market.

Firstly, they have to accept that they don’t have a SWIGA guarantee and the lesson learned should be that private clients should insist on a 25 year guarantee before signing up for having solid walled insulation installed. You’ll find that there’ll be no arguments from the installer if business depends on it but I think it is a rather large loophole in the process and damaging to the industry that they would not afford the same level of protection to private buyers of these systems. We can discuss the value of different guarantees but these are expensive systems and I would recommend a 25 year guarantee, if for no other reason than to guard against contractor insolvency.

Secondly, the purchaser has a contract with the installer, if they do not have a written contract then terms are implied. Unless a contract is executed as a deed then it is a simple contract and any claims for breach of contract must be commenced within 6 years of the date from which the cause of action arises. (12 years when the contract has been executed as a deed)

Contractual claims normally relate to latent or patent defects, which generally give rise to claims under breach of contract. However…  it is not unusual for buyers to discover latent construction defects many years after time limitations have lapsed and where latent defects are found outside of the 6 year period for breach of contract, then clearly this presents a problem. However if you suffer damage arising from negligence then the cause of action arises when the claimant suffers damage (when the defect appears)  rather than when the breach of contract occurred. (Latent Damage Act 1986). The complexity comes from the fact that damage is suffered from the defect occurs, rather than when it is discovered by the client. Thankfully negligence claims are not time barred provided that the buyer instigates proceedings within 3 years of discovering the defect.  That may not be as rosy at it initially sounds since all negligence claims must be commenced within 15 years of the contractual breach. Still, I hope that  any buyer of construction services realises that the level of contractual protection extends well beyond the 12 month guarantee that many builders say or think they offer, potentially up to fifteen years for tortious claims.

Be warned that contractual rights do not transfer to subsequent building owners and any protection that would have been afforded to the original buyer under contractual terms and conditions will not apply and subsequent loss would be regarded by the courts as pure economic loss.

Whilst I advise all clients to explore all reasonable options to resolve disputes without referral to the courts, very occasionally court action is inevitable. Hope for the best and prepare for the worst is my advice, and with this in mind you should always keep meticulous records of all transactions and communications with your builder. The Civil Courts will always look to see that you have done everything that could reasonably be done to avoid court action and I would always advise that you try to keep legal and professional fee’s proportionate to the value of your claim since even if you are successful then any costs awarded are likely to be proportionate to the value of your claim. You are highly unlikely to recover £10k in costs on a claim also valued at £10k.

You will often need an independent professional report fully detailing the defects and the cause of those defects because the Latent Damage Act requires that you have “the knowledge required for bringing an action for damages in respect of the relevant damage” this means knowledge “of the material facts about the damage in respect of which damages are claimed,”  and you are also required to prove “that the damage was attributable in whole or in part to the act or omission which is alleged to constitute negligence.”

If you have evidence that your EWI system was installed negligently and can prove it, as I believe the client does and can, in this particular case, then in fact they will have potential redress to the civil courts for another 15 years. A sobering thought for any other installer who insists that they have no contractual obligation to correct defective construction works. However, this is currently a fairly straight forward claim for damages under breach of contract and even the six year protection afforded will not be seriously tested since the system has already failed due to a high number of  patent and latent defects.

If we are required to intervene on these cases then we work with an excellent construction lawyer who is also a Chartered Quantity Surveyor, so that simplifies and shortens any technical discussions once the site investigation is completed, which can a real benefit in moving the issues forward quickly and cost effectively.

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A Case of Pillowing or Mattressing? – EWI Failure

A Brief Explanation of Failure Modes in External Wall Insulation Systems

Screen Shot 2015-10-11 at 20.05.42We were recently asked to look at an EWI failure for a potential client. This was a homeowner who had spent £15k on having their home externally refurbished with an EWI system. At circa £100 per square meter this was an expensive system but they’d done their homework and were happy to pay a little extra because they believed that they were buying the best. I was more than a little alarmed when they explained that the system had been installed in 4.5 days and indeed, this did not align with  the 3 week programme that had been described by the installer.

Thankfully the  homeowner had taken photo’s throughout each stage of the installation and this made it easier to understand exactly what had gone wrong, even ahead of doing any invasive site investigation work. Our understanding is that within days of the installation being completed the homeowner noticed that the underlying EPS insulation boards could be seen through the finished coat of decorative render. This was initially noticed at night when the external uplighters shone against the render but as the days went by the boards also became clearly visible during the daytime.

The system designer looked at the problem and described ‘pillowing’ in the EWI system though no explanation for this phenomena was presented. Their proposed remedy was to strip off the render back to the EPS boards and to re-apply the base coat, mesh and finished render; a proposal that we do not feel will go close to addressing the problems on this installation.

In fact, we didn’t agree that this was pillowing but we can understand why the term was used since the insulation boards can also be seen under the finished render when either pillowing or mattressing occurs.  Both effects are generally linked to poor adhesion when the board is bonded to the substrate unevenly across its surface,  for mechanically insulation fixed boards the same effect could also occur where the recommended fixing pattern has not been followed.  We recently encountered an installer who fully bonded phenolic boards to counteract board shrinkage but we’re not aware of any evidence proving this proposition and our view is that it will have little or no effect on the problems caused by board shrinkage, our solution to this problem is not to specify Phenolic boards.

Whether you see pillowing or mattressing can depend on external temperatures and pillowing is linked to warm temperatures, whilst mattressing is linked to cooler temperatures.  The amount of adhesive recommended varies from system to system and for this system a minimum coverage of 40% was recommended.  There is a slight anomaly here since generally you should avoid voids between the insulation and substrate to prevent a stack or chimney effect, this is a naturally induced vertical flow of air that is to be avoided in these systems.

Poorly Installed EWIS

IMAG1882

Poorly jointed EPS

20150708_172146

Insufficient base coat application

20150708_173127

Exposed edge bead

20150708_172320

Poor coverage to reinforcing mesh

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Bead prior to decorative coat application

20150708_172919

Mesh prior to decorative coat application

20150708_172344

Poorly trowelled base coat

20150708_172649

Poorly trowelled base coat

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Poorly trowelled base coat

Screen Shot 2015-10-11 at 21.27.28

EPS boards visible under decorative coat

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EPS boards visible under decorative coat

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EPS boards visible under decorative coat

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EPS boards visible under decorative coat

IMAG1878

Poorly installed EPS

IMAG1870

Poorly installed EPS

IMAG1877

Poorly installed EPS

IMAG1835

Uninsulated reveals

IMAG1876

Poorly applied corner bead

IMAG1841

Poorly jointed EPS

IMAG1885

Timber pattressing and poorly jointed EPS

IMAG1888

Timber pattressing and poorly jointed EPS

IMAG2046-2

Failed sealant 8 weeks after installation

Interestingly, in this particular case, the system designer ordered some 20mm thick insulation boards that we understand were to be used to level off the substrate but they were never used by the installer. Once the EPS boards were installed they should present a  ‘smooth in-plane finished surface’, any high spots should be rasped or sanded to achieve this if required. The installers mentioned to the homeowner that they were short of base coat but when questioned as to why they hadn’t ordered more, said that they’d ‘managed’ with what they had.  Clearly they didn’t because the the mesh should be free of wrinkles and fully embedded in the base coat with the mesh pattern just visible on the finished surface. The system  logo should not be visible through the cured reinforcing coat and yet it was clearly visible. The manufacturer of this system also states that supplementary mechanical fixings are used with the adhesive insulation systems, especially during the strength development phase of the adhesive curing and yet supplementary fixings were only partially used for reasons we cannot fully understand. You will see from the image slider that the insulation boards are clearly visible in the finished EWI system and it is our belief that the reason for this is simply down to the fact that the base coat was too thinly applied to fully cover the underlying EPS boards. The effect got progressively worse in the days following installation due to shrinkage in the  base coat and decorative coat as it fully dried after the installer left site. They may have applied the term ‘pillowing’ as a generalised term to describe a situation where the underlying boards could be seen but as we said, we do not believe this is the technically correct description. The standard of installation is so bad on this particular property that we don’t believe that the three foreign sub-contractors who installed this system were certified installers, site communication was very poor due to language issues and they certainly weren’t managed during the process. However, we don’t want to mention the particular system that was used because we think this is probably irrelevant at this point. It is yet another perfectly good EWI system that has very poor site specific design and installation.

We have an update to this particular tale… 2 weeks after writing this blog and approximately 6 weeks after installation the system has developed its first moisture blister, we expect this to be the first of many but we’ll continue to monitor whilst the system designer provides a second technical report into the alleged reasons for failure. For some reason the first technical report was never made available and will never see the light of day though I suspect that may be due to our involvement.  We’ve inserted two images, one of the area where failure has occurred prior to application of the reinforcing mesh and topcoat and another of the finished render showing the moisture blister.

IMAG2081

Moisture blister near base of downpipe. Note terrible edge detailing on render.

Note poor detailing at base supporting rail

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A Tale of Two EWI Failures – EWI Case Studies

Lessons Learned from Two High profile EWI Failures

We have been monitoring outcomes for quite some time on a number of  high profile external wall insulation system failures; all of which occurred on high rise blocks in Bootle, Wigan & Glasgow. We have reviewed the Wigan failure and have a clear picture as to why the render system failed at Scholes Village but we cannot yet share this information.

The failure at Stanley House in Bootle has I believe now been rectified but the cause of the failure was never published and we believe that the clients (One Vision Housing) even signed a gagging order as part of the court settlement. You can see evidence of that failure in the next video clip.

Stanley House EWI Failure

Whilst doing continued research on EWI failures we came across commentary relating to the Stanley House failure that has been published by one of the consultants involved in the failure.

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After the initial gagging of information it is good to see that a clear picture has now emerged with regard to the cause of this failure; however it has taken  years for this information to emerge. The failure mode is unsurprising to us but begs the question as to who was monitoring the quality of this work on site? Missing metal cladding fixings are a very easy thing to spot  and correct, even to the least discerning eye. There was an immediate and urgent need to install a mild steel mesh around 6 buildings but we are unsure if this was installed as a temporary or permanent measure. There are some forms of insulation such as phenolic, that once wet need to be removed from the building. It will be interesting as we move forward to see if there are attempts to reinstate or repair  failed and saturated EWI systems. Some systems such as those containing XPS insulation will present greater flexibility for repair and re-instatement than others.

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Another EWI Scheme with Insufficient Fixings

We next come to a case that has always been incredibly difficult to uncover information about… GHA’s Mini-Multi blocks. These blocks experienced failure very early after completion in 2010 and we saw reports of ‘extensive blistering’ in a number of blocks. The main contractor, ROK, went bust but they were not the EWI installer and we are unsure who ultimately footed the bill for remedial works.

The consultant dealing with this also published some recent findings with regard to these failures and we believe that remedial works are now complete; however we have to say that we find their reported reasons for failure as a little unusual.  The consultant stated that ‘The render on GHA high rise blocks had started to blister. The failure was identified as being due to a lack of water permeability in the topcoat.’  This directly contradicts information given to GHA residents by GHA representative, Ian Duff, who stated that ‘moisture and evaporation got in behind the over cladding.’  We are unsure if it ‘got in’ through failed building joints or whether wet insulation was installed but for either eventuality, no amount of permeability in the topcoat was going to lose this moisture through an evaporative process.

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GHA’s Repaired Mini-Multi Blocks

The idea that these systems absorb moisture by the ‘overcoat’ principle is simply wrong and if they take in water through failed building joints or if wet insulation has been installed due to poor site storage facilities then the render coat is not designed to lose this moisture by permeability or breathability. These are weatherproof systems and water ingress will usually write off the affected underlying insulation. We always believed that such premature failure and blistering was a sign that the insulation was wet when installed but we are now even seeing systems installed with no sealant at all around windows and other critical junction details and these critical omissions would also be responsible for such rapid system failure.

There are two critical lessons to be learned from both these failures:

  1. Clients must have a robust and independent system in place for the quality management of works.
  2. Clients must understand their specification &  the terms of their BBA approval to ensure that there is no diversion from the agreed specification.

 

Postscript

An interesting discussion developed after this blog was posted with regard to the GHA EWI failures. Two separate interested parties told me that occupancy issues were believed to be a factor in these failures. The logic behind this is that the flats had a high number of  ‘stay at home’ occupants, possibly retired or unemployed. Therefore flats experienced a higher than average level of relative humidity, which permeated through the walls into the EWI system insulation. This is an interesting theory but given the rapid system failure it is not one that I think holds a great deal of validity. Moreover, if occupancy issues are a significant risk factor for EWI failure then you would need to complete a condensation risk assessment  for every project during the design process. (This does not mean a risk assessment for interstitial condensation, which is something I’d expect to see done on every project anyway)

In theory, it is a reasonable proposition and of course we know that EWI should not be installed on wet walls because evaporative moisture can  and does cause significant problems. However, there is no need to hypothesise about this potential factor since internal data logging can easily monitor and record internal environmental conditions, thereby providing a complete picture with to regard occupancy issues. Secondly, hygroscopic moisture content (HMC) and capillary moisture content (CMC) can also be checked and recorded in the building fabric to check if internal relative humidity is in fact having a significant impact on total moisture content within the building fabric. If the building fabric is dry then occupancy issues are not a significant factor.

 

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The EWI Industry: Time for Reform?

I have previously written about the risks of installing External Wall Insulation without due consideration to the building, the system design and adequate site storage facilities and site management. The article, titled, ‘The Risky Business of Covering Up’ was  published in the CIOB’s Construction, Research and Innovation Journal can be found here under the heading ‘published material’…

Useful Information

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EWI Install to High Rise Block

I have been predicting that we would see a glut of external wall insulation failures for the last three years and I am now seeing strong signs that my prediction is correct and I suspect that even I have not fully grasped the scale of the problem yet. I am currently working on a supplementary article to follow the piece I wrote in the CRI Journal and to that end have a trip to Germany planned to review their EWI system failures.

To my mind the industry is simply not open enough to airing and discussing their failures and in fact has a very strong defence mechanism that kicks in to counter negative web publicity wherever it appears. I have experienced this first hand when I recently blogged that ‘The Defects are Often Built In.’  I was following and photographing a Midlands EWI High-Rise installation purely as an academic piece and was careful to not mention the contractor or the particular scheme. Apparently I was not careful enough because within 24 Hours I received a call from a manager who project manages these schemes for the contractor concerned. He explained that he had received a call from a ‘concerned industry insider’ and that he wanted to discuss my blog. In fact he was incredibly reasonable about the blog and was more concerned about the quality of work seen in my blog pictures. One picture was flagged with a large number of defects and he was in complete agreement that the work was appalling. His prime concern was being proactive in getting the work rectified before premature failure placed his employer at considerable financial risk. We had a very professional discussion and I closed by commending his approach wishing him good luck in getting the work rectified. Twenty four hours later I received a second phone call from the Managing Director directly responsible for the site and the work. His approach was very different, he claimed that the photograph was only good for the time it was taken and that I didn’t know what had happened afterwards. His ‘experts’ were telling him that the work was good and there was a reason that mechanical fixings were not fully installed at the same time. I disagreed and stated that the installation process was clearly detailed in the BBA certificate. He suggested that they had an installation process that had been signed off by their designer but of course if this deviated from the BBA certification process then the BBA certification process would no longer be valid. In essence he claimed that there was a reason that only one mechanical fixing was being installed into a 1200 x 600 insulation panel until the adhesive had dried, after which point they would go back and install the extra fixings required. This was patent nonsense because their approach to installing insulation panels was inconsistent on every high rise block and every elevation of each high rise block. Some panels had zero fixings, some had one, some had two some had three…. You get the picture. If there was a separate site installation process deviating from the BBA certificated process then this in itself is a problem but clearly there can only be one process and inconsistency of approach demonstrates clearly that the process is not being followed or managed. There was a subtle suggestion that coming to site to discuss how things are done might present some ‘opportunities’ for my business whilst continuing to run with my damaging blog might be damaging to my business. I try to be pragmatic wherever possible and compromised on removing the name of the town, changing the photograph to one more palatable and removing the project value so the blog was as anonymous as it could possibly be. I refused the suggestion that I should take down the blog altogether.

What really fascinated me about this conversation is how quickly the EWI industry defence mechanism kicked in. I was told that the web is scanned daily for negative publicity and a concerned party from within the EWI trade association contacted the contractor within 24 hours of my blog going live. I was told that there is a possibility that my blog or website was possibly being specifically monitored due to my previous article on EWI system failures. I’m well aware that this sounds like some fantastic conspiracy theory but its rather more simple than that… EWI is big business and confidence in EWI system installations has to be maintained to keep the gravy train on track. Perhaps the great irony in all this is that I am a huge fan of EWI systems but my view is that they are consistently let down by inadequate design and  poor site practice and installation and some reform is needed.

What I don’t want to do is get into criticizing individual contractors but I am seeing more EWI insulation work done poorly than done well and I hold a view that inadequate design and poor site quality control are often the primary causes of failure. My research and writing on EWI failures is purely academic and aimed and at raising awareness with clients of the need to stringently manage site works. Secondly, clients need to understand their ongoing maintenance obligations with regard to protecting the long term guarantees on these systems. A client may have a £1m EWI system installed to a high rise block that he believes is guaranteed for thirty years but if they do not have a regular maintenance regime in place to inspect building joints, particularly around window and door frames, then they will hand their EWI system guarantor a rather large get out clause should the system fail prematurely. In my experience a very small minority of clients set up planned maintenance regimes once these systems are installed and yet the requirement to set up a regular inspection and maintenance regime should be clearly presented to the client at project handover. I have managed millions of pounds worth of EWI installs and not once was this requirement set out or explained to the client. The failure to set up a regular maintenance regime may well prove to be a great get out clause in some isolated cases but my experience is that, more often than not, the defects are built in and as my construction solicitor recently commented, ‘You cannot maintain a defect.’

The Department of Energy and Climate Change insisted that EWI systems came with a 25 year guarantee to facilitate rolling out EWI systems to the mass market and to that end SWIGA provide a guarantee that covers materials and workmanship.

The problem with SWIGA is twofold:

Firstly, SWIGA was essentially set up by the EWI industry and it is not what I would call an independent body. Secondly, if a client does experience EWI system failure that is reported to SWIGA then SWIGA will appoint the system designer or manufacturer to investigate that failure. This is hardly an independent investigation and one that is bound to develop into a circular argument as installers then appoint their own experts to counter the findings in reports generated by designers or manufacturers. I’ve seen this first hand on numerous occasions now and can see an EWI industry heading towards a tangle on internal conflict and dispute until they accept that they cannot self-regulate to the degree that they currently are.

EWI systems will continue to be a potentially great way of dealing with technically obsolete and ‘hard to treat’ properties but the industry is in danger of leaving a legacy of system failures and a subsequent tarnish that will be very difficult to remove unless wholesale changes are made.  I would suggest that adequate reform rather than the management of negative publicity is the way to maintain consumer confidence in EWI system installations.

 

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EXTERNAL WALL INSULATION: THE DEFECTS ARE OFTEN BUILT IN

External Wall Insulation Defects

External Wall Insulation Defects Being Built in

External Wall Insulation Defects Being Built in

Wherever possible we try to take the time to monitor ongoing external insulation schemes and we are currently monitoring two Midlands schemes to add to our knowledge base. The picture of the high rise block clearly shows that EWI defects are being built in and this is fairly obvious even to the casual passer-by. The insulation panels have been bonded with adhesive to the block but this does not mitigate for the reduction or complete omission of mechanical fixings. This is a high rise scheme and it is our opinion that premature failure is inevitable. The second scheme is a low rise scheme so on the upside, if things do go wrong then it is easier to inspect and access costs are not prohibitive for remedial works. However, this is a scheme using EPS insulation boards. We have to assume that the boards have been fixed with adhesive but again this does not mitigate for the lack of mechanical fixings; in this case only one fixing per board has been applied and there are no additional fixings around window and door openings. Generally these need to be placed at a maximum of 300mm centres around window and door openings.

Previous Research

OLYMPUS DIGITAL CAMERA

Low rise scheme using EPS boards. Note lack of hammer fixings

We had a paper published in the Construction, Research and Innovation Journal in December 2013, entitled ‘The Risky Business of Covering Up.’ This paper heralds an early warning with regard to our belief that we will see a glut of external wall insulation failures, particularly on high rise blocks. These systems are often supposed to have a 30 years design life but very few clients will achieve these life spans unless they understand the requirements of their individual system BBA certification and stringently monitor site works to ensure that the BBA certification is being complied with. In our experience, there is often a complete failure to adhere to the BBA certified installation process.

EWI Installers are Getting Nervous

There was an extremely interesting development to this blog that I have been meaning to deal with… In fact I was contacted by the constructor concerned and requested to take the blog down. I’m not prepared to do that, it’s an academic blog that is aimed at continuous improvement so I do not feel that it serves the industry well to keep these issues hidden. The point I particularly wanted to deal with was the claim that pinnings to the insulation boards were only temporary and the intention was always to go back and install the required amount of hammer fixings once the adhesive had dried. Of course to try and confuse the issue with this claim is akin to admitting that you are putting the general public at risk… These systems are load and wind tested according to the number of hammer fixings installed and adhesive bond does not form part of the load test assessment. If a system insulation board is required to have 5 hammer fixings then this is required to satisfy structural adequacy. If you then claim that a reduced number of temporary fixings have been installed then you have actually installed a system that is structurally unsound (albeit temporarily) and at risk of falling from the building until the required number of permanent fixings are installed. I do hope that this is not a common approach for installing EWI but I really don’t believe it is since the process of installing ‘temporary’ pinnings would neither save time or serve any useful purpose.

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