A blog post

Cavity Wall Insulation – what are the benefits?

Posted on the 28 August, 2009 at 2:54 pm Written by in Case Studies, Cavity Walls, Damp

Cavity Wall Insulation
(What are the benefits? …..…..DAMP)

From October 2008 all domestic buildings (being built, rented or sold) were required ‘by Law’ to have an Energy Performance Certificate (EPC) to help improve the energy efficiency of the building. The EPC provides an ‘A’ to ‘G’ rating for the building, ‘A’ being the most efficient and ‘G’ the least and to-date a ‘D’ rating is currently being banded as the average.

It is claimed that around a third of heat loss in a house is through its roof and walls and currently there is a government drive (supported by television advertising and the offer of Home Improvement Insulation Grants) to encourage home owners to increase loft insulation and also to fit cavity wall insulation, as it is claimed this can save on average around £180 per annum on heating costs!

However were you aware that by installing cavity wall insulation, whilst you may well be saving some money on fuel costs, you could also be creating a major expense for the future……..damp!

Example of cavity wall insulation

Example of cavity wall insulation

The cavity wall (as we know it) dates back to the early 1900’s and is commonly found in the coastal areas around Britain, used to reduce the risk of rain penetration. In the 1920’s, local building by-laws encouraged the construction of the cavity wall and by the 1940’s it had become the Industry Standard. The familiar cavity wall (as we know it) is two leaves of brickwork, forming a 60mm cavity and tied together with metal wall ties.

Even back in the good old 1970’s concerns were being expressed over Energy Conservation and home owners were then being encouraged to introduce loft insulation and it wasn’t long after that cavity wall insulation was also being recommended.

Fill your cavities with foam, polystyrene, mineral wool or any other material you can introduce through a small hole in the wall and you will save energy and loads of money. Sounds good, but what if by introducing this insulation you increased the risk of damp to your property, which in turn would cause internal decorative spoiling, plaster damage, fungal decay to  structural and joinery timbers and also accelerate the risk of corrosion to the metal wall ties.

Could that really happen? Well the answer is yes and it is.

Paul Carter, the principal of Premier Heritage, has investigated hundreds of buildings over the past 20 years of so, where damp has affected internal decorations etc and found that the damp present was due to bridging of the cavity by the earlier installed insulation materials. Whilst some of these cases were wrongly diagnosed by others as rising damp, most of these buildings (if not all) retained a physical damp proof course, the newest being a 1980’s brick built bungalow in Hampshire.

Ok, lets put this into perspective, there have been thousands of cavity built houses within the UK that have been insulated and a good majority of these don’t currently have nor will ever have a problem with damp. But there are a great number that have and no doubt more will be affected in the years to come! 

Increased rainfall in past years has resulted in a noticeable increase in damp problems affecting conventional cavity-constructed housing, due to moisture penetrating / bridging the cavities and in particular on the weather prevailing elevations and this isn’t a problem relating to current rainfall, but a gradual build of damp over many years.

Rainwater driving into the masonry of a building can penetrate the outer leaf brickwork leading to the wetting of the insulation materials, increased damp penetration and a reduced thermal performance of the material. Poor construction methods, mortar and perp joints, debris within the cavities, dirty wall ties and poor installation procedures by installers all contribute to the overall problem, which generally will result in the need to remove the insulation, which is not only expensive, but will almost certainly cosmetically scar the building when finished. Unfortunately it doesn’t come out through the same hole through which it went in!

So how do you avoid this problem? Well there’s no easy answer to this other than to look carefully at the building’s construction (porosity of building materials) and its exposure to the prevailing weather conditions. If having then decided to proceed, ensure that the chosen contractor / installer, during the survey, checks the cavities  and cavity trays for debris and dirty wall ties, but more importantly offers a system and material that guarantees (preferably insurance backed) that the materials being installed will not transmit / bridge moisture through and into the internal wall!

Alternatively, if you’re still unsure then don’t install.

Examples of Cavity Wall Insulation causing damp:

Cavity Foam Insulation

Cavity Foam Insulation

1970’s block constructed bugalow with poorly installed cavity foam insulation and debris bridging moisture via wall ties, cost around £800 to remove and rectify internal damage caused.

Polystyrene bead cavity insulation

Polystyrene bead cavity insulation

1930’s brick constructed house with polystyrene bead cavity wall insulation. Caused extensive damp to rear elevation walls, cost in excess of £3,000 to remove insulation and rectify internal damage.Polystyrene bead cavity insulation
Polystyrene bead cavity insulation

Polystyrene bead cavity insulation 2

1920’s brick constructed house, south facing elevation with polystyrene bead insulation and poor quality mortar. Caused extensive damp to internal decorations and accelerated corrosion of wall ties (rusting ends just visable), cost in excess of £3,500 to remove insulation and install new wall ties.

some comments

There are currently 102 of them
  1. Monica Maguire 25 July 2012 at 9:48 pm permalink

    We have a detached house built in 2005. The brace wall in on the outside of the house. On a wall upstairs where the chimney would be has become boast in 2 spots each about 10cm in diameter. Someone has diagnosed that we have dirty wall ties, someone else has said that we need to put a cap on the chimney and put on fires to dry it out. Which is it most likely to be and how much is it going to cost us to put right?

  2. Dave 29 July 2012 at 6:10 pm permalink

    Anita Pandolfo..
    I had a similar problem and sealed the external walls. Unfortunately it made the problem worse, as the bricks could no longer ‘breathe’ to allow moisture in the cavity to escape.

  3. kal 7 August 2012 at 8:57 pm permalink

    Hi you have to make sure that by sealed the external walls you ave to use a sealer that allows the wall to breath but is also waterproof never use pva. That seals and does not let the wall breath. My opinion would be do not get cavity wall insulation if it goes wrong it costs a lot to repair as i have had major probs. You could concider external insulation it’s more expensive but most council houses are getting this type done. The cavity is left intact with foam boards attached outside and then placterd and renderd over.

  4. kal 7 August 2012 at 9:16 pm permalink

    Example of external wall cavity


    Must look at this if your considering cavity wall



    AS above i would avoid mark group


    Have a look at this link map of areas not suitable for cavity wall well you be the judge this is just my opinion.


  5. ian 4 November 2012 at 9:37 pm permalink

    had cavity walls done 2007 had nothing but trouble since damp spots all over internal walls upstairs and down and condensation that is running off the window sills and walls and no warmth benifit that we can see

  6. Anthony Whelan 27 December 2012 at 2:27 pm permalink

    I have had a1960s bungalow insulated through injection of polystyrene beading in the block-built cavity walls. Since then, I have not noticed any visible signs of damp (condensation, black mouldy zones, etc.), but there is a strong musty smell in a number of rooms. The floors are of wooden boards, there are ventilation vents at ground level (i.e. under the level of the boards), and there are enough chinks between the boards to let some air pass. I’m beginning to think that I should also insert vents higher in the ŵalls to enhance air circulation. What do you think?
    Thanks, Anthony

  7. Julian 5 January 2013 at 3:19 pm permalink

    My neighbour had his walls filled with foam. Then his house went completely damp and so did ours (sodden) he then blamed it on me, showing me his rotten woodwork. I had nothing to do with his damp that he caused yet he again knocked on my door and blamed me again. I told him you should NOT put foam in the walls of an old house (1930 built). NOw we have to put up with months of this idiot scraping /drilling and tapping on the walls to get this crap back out, whilst we all work on NIGHT shifts for NHS! You couldnt make it up. I should sue HIM and claim for the damage but we just dont want the trouble.

  8. S S Hall 10 April 2013 at 11:37 am permalink

    I had cavity wall insulation fitted some years ago on the understanding it would keep the house warm without any side effects.Not so, in the cold the windows condensate,previously they never did.The reveals are now damp the wallpaper peels off black mould has appeared. I have complained to the company that carried out the insulation, they suggested leaving the top opening window slightly ajar to give some air circulation. however this would leave the house insecure as well as defeating the object of draught proofing.
    I wish I had never had this work carried out, it has ruined the decorating in every room in the house.When I asked the contractor if they had any other similar complaints they confirmed they had but not many and that they had seen a lot worsr than mine.I suggested that they should warn people as to what might happen prior to having this work carried out I am desperate to have my house back to how it used to be and would be happy to put up with slightly higher gas bills than be left in the situation I am now in, and with no prospects of the contractor being willing to do anything to resolve these issues. I would be grateful for any suggestions on how these problems can be resolved

  9. Claire Eades 2 March 2014 at 7:56 pm permalink

    My parents had CWI installed by the Mark Group about four years ago. Their house is now ruined. They have never had a damp problem before. I will not let this rest until justice has been done for them and other house holders like them. This is a Govt initiative causing wide spread misery.

  10. Mike Lamacq 4 March 2014 at 4:50 pm permalink

    Re the comments by Claire Eades March 2, 2014. We have also suffered from this problem. It will cost approximately £3500 to fix INTERNAL damage, insurance company do not want to know the causes (cavity wall infilled by Warm Front – under the auspices of the Gov) so we are left to sort out the problems on our own. Quote to rectify the outside wall problem in the region of £5000. This will involve cladding the walls with cement/fibre boards fixed to battens. Have seen various reports of similar problems but nobody wants to know.Would be interested in any helpful comments.

  11. Adrian monk -steel 28 March 2014 at 12:34 pm permalink

    Hello , just read the comments ,we are being pestered to have this done, my wife won’t believe me when I say that our house won’t be able to breathe ,she thinks I’m mad !there’s a gap between the inner and outer wall for a reason , to let the house breathe and keep the moisture/damp from getting through to the inner wall, and keeping the inside of the house dry and free of damp too don’t be fooled do your homework first, don’t just believe what you read I don’t want to make the mistake and find out that it’s to late to go back!

  12. Claire Eades 5 April 2014 at 7:11 pm permalink

    The Mark Group have caused 10000 worth of damage to my parents’ house. CIGA admit that it wasn’t installed to BBA standards yet no one takes responsibility to remove it. My parents are in their 70s. I have had a direct email from Ed Davey’s office stating that no Govt money is involved yet my parent’s were told that the Govt was funding it by a Mark Group sales person. This is on their website.

    Cavity Wall Insulation prices vary depending on the property but, thanks to government funding schemes such as ECO, you may qualify for a Cavity Wall Insulation grant to help you with the cost of insulating your home. For more information of funding for Cavity Wall Insulation, please check out our Frequently Asked Questions.
    Find out if you qualify by using our free online funding tool now.

    I have copied this to Ed Davey but guess what? NO RESPONSE

    Sent from my iPad

  13. Claire Eades 5 April 2014 at 7:20 pm permalink

    Mike I have set up. Cavity wall insulation causes damp problems page. You are welcome to join it. I have also read reports and have discovered that the energy companies are responsible for quality assurance. They follow up only 5% and of that they admit to a 14-17% failure rate. However I have also read criticism that CIGA is not independent as it is funded by the installers. Ofgem are aware that the quality assurance process is not rigorous. Jeffrey Howell of the Sunday Telegraph is behind us but pretty much a lone voice. He says that people like me start to raise the issue but once our own problem is sorted we drop it. If we network we can raise the profile of this.

  14. Claire Eades 5 April 2014 at 7:22 pm permalink

    Everyone Email Ed Davey the environment secretary . Don’t let it rest.

  15. Nikki 14 April 2014 at 10:06 pm permalink

    We have been seeing damp problems too since CWI and loft insulation in out victorian/edwardian terrace. This is obviously a serious issue for many people.

    I know the drive for this ‘insulation’ is about energy use reduction in order to mitigate carbon emissions, but clearly there are unforeseen side effects of the methods.

    New and properly tested methods of reducing energy consumption is needed.

  16. LN 19 April 2014 at 9:37 pm permalink

    The whole idea of ‘sealing in the energy’ is madness. houses need ventilation, and when one installs any kind of boiler, fire, stove one must now drill holes in doors and walls to provide this because windows etc are almost airtight. It’s most unhealthy and all the insulation is a big scam. When we had our water tanks unlagged they helped keep the house warm, the heat wasn’t really ‘lost’. Now I have friends who insulated the loft so well that all their header tank and pipes froze and burst in the freezing loft, huge expense for little if any benefit.

  17. Debby Jones 4 May 2014 at 5:37 pm permalink

    We have just had our cavity wall insulation removed by British Gas after we complained to CIGA. We were baffled as to why the rear of our house was damp. We spend thousands having new windows installed, roof repairs and finally having the back of the house re-rendered. We had one of our internal rooms re-plastered only to discover perfect damp circles appearing on the walls and semi circles appearing near the floor. British Gas said this was caused by the material used to fill the cavity (rock wool). Rain was driving through the rendering, soaking the rock wool which in turn was soaking the walls. We wish we had never had it in the first place, it has caused us so many problems and expense.

  18. Graeme 8 May 2014 at 2:28 pm permalink

    All, firstly many thanks for your posts on here.

    There’s guys currently installing for free white mineral wool on our street at the moment in Halifax,UK – but after researching it and reading this blog I’ve decided not to have any installed. I’m sure it may work fine in many cases however the ones that don’t sound to need a very expensive solution to try and fix. The idea does sound mad to me, we do after all as an earlier comment mentions have that gap for a reason.

  19. Colin Hill 26 June 2014 at 9:19 pm permalink

    Have just come across this thread so hope it is still open. Would like to know developments.

  20. Claire Eades 11 August 2014 at 8:47 am permalink

    We managed to trace our installation back to Eon who subcontracted out to Mark Group. We found this info by contacting Nathan Shelley at Ofgem. We had no idea at the time that Eon were behind it as it was sold to us as Govt funded. To be fair Eon have been efficient and always responded when they said etc (unlike MG and CIGA) Eon argue that they don’t hear of many complaints. I did explain that no one knew under CERT that energy companies were behind it.

    MG have agreed to foot the bill for removal and the rest is still under negotiation. We are still in the middle of it. 2.5 years later.

  21. robert thomas 28 August 2014 at 4:13 pm permalink

    I moved into my property in May this year and discovered damp throughout. It was only when the render was taken off that i discovered the cavity wall insulation which was soaking. The Mark Group who installed have been an absolute nightmare to deal with. They took seven weeks to send someone out to assess the problem and i am still waiting for extraction. They have even asked me to pay for the scaffolding to extract which i have refused.
    The only way forward for me would appear to be legal action. Avoid at all costs

  22. Claire Eades 8 September 2014 at 9:46 pm permalink

    Hi all

    Steer clear of retrofit cavity wall insulation. The concept is flawed. I have been dealing with this for four and a half years and only just succeeded in having it removed.

    The term surveyor is used loosely. Many of these jobs are OTE and paid piece meal. Surveyors are paid only when they deem a property suitable AND work takes place. They are sales people and nothing else.

    CIGA is worthless. If you are lucky to get a response then they will tell you that the property is at fault. They will pick on any feature such as a car port or flat roof. Literally anything they can find. The BBA are marginally better but still collude and probably won’t send you the report even if it’s in your favour. It’s a disgrace.

    Ofgem and the DECC, trading standards, Citizen’s Advice all turn a blind eye to this whilst innocent and sometimes elderly and vulnerable people have their lives destroyed.

    CWI can be removed. A word of advice. Avoid any company who installs and removes. Nice double pay day. Avoid any company that tells you it can be removed through the same holes. It can’t!
    Avoid any company that pays piece meal per extraction. Extraction requires a skilled brickwork specialist. Some extraction companies may be a branch of an installation company.

    Mark Group are terrible evidenced by review centre/Mark Group. Listen to You and Yours BBC Radio 4 August 13th 2014 it’s on iplayer. They are referring to the Mark Group

    Be careful!

  23. Carole 17 September 2014 at 9:26 pm permalink

    Hi everyone I how this topic is still open as desperate for some advice and suffering similar issues from cavity wall insulation. Bought a house found out I had a damp problem along lower level in hall . surveyor advised me due to retro cavity wall insulation as house was in area of penetrating wind blowing rain . Finally I I was able to trace the ciga guarantee and name of installers . Year after I bought house managed to get insulation removed by company. Earned to start drying out did readings with a damp reader they dropped . Had rain they increased call insulation company back they looked with camera removed what they missed ! Waited again when it rained readings went up spoke to surveyor as I know render is blown in places . He said can only be something in cavity allowing water to bridge get insulation company back check for insulation in cavity or around wall ties. They did that today with cameras and said cavity is totaly clear not even bricks in it ? I’m pulling my hair out getting someone to check under roof tiles tomorrow as don’t know where to go ? Any ideas could damp readings be increasing on inner walls after rain Cause plaster got damaged ? Is insulation company missing something or my surveyor ? Help has anyone had a similar problem

  24. john 17 October 2014 at 10:51 pm permalink

    just had knaff supafil added to my house, day 1, and it is warmer, no damp problems previously, but I sit in fear reading this thread. just hope I am a lucky one. it would be a first!!

  25. Claire Eades 31 October 2014 at 6:16 pm permalink

    Please feel free to message me directly

  26. E Bell 4 November 2014 at 12:02 pm permalink

    I have been following the comments on Premier Heritage for some time. Moving into our 1930’s semi 7 years ago we have spent that time trying to resolve various damp issues on a gable north facing wall. CWI was fitted prior to our purchase and the house had been empty for a year.

    We had the underfloor ventilation/debris sorted, additional airbricks, wall repointed etc. We had two“reputable” damp companies out who we hoped would help, but just said get a new dpc and insisted nothing to do with cwi! I later contacted an independent specialist (fee charging) but he was reluctant to visit as were a bit of a distance – no RCS indepenpent seems to cover north east area but I do think an independent RICS surveyor, specialising in damp is helpful.
    We had followed all logical paths when the damp patches (which would come and go) developed in a more patterned form -randomly on the wall. Looking outside we thought this correspondeded with our wall ties. At this point I researched more online and this is when I came across Premier Heritage and learnt so much more about CWI issues. I rang CIGA and obtained the warranty and from there we knew that interfering with the bricks and delving into the cavity may affect the CIGA warranty, so we rang the installer to come out.

    The installer (KNW) said immediately that they could see an incorrect drill pattern had been used on installation and it was likely that cold spots had developed. They offered to correct this and reblow the insulation. Whilst I did not argue with this I did not feel it was sufficient. I had been taking photo’s of the damp and showed them the problems we had and asked that they remove some of the bricks to check the cavity. They agreed to do so and found that the cavities were full of debris, up to a metre high in some places. I was pretty shocked that the cavity had obviously been filled with cwi when it had so much debris. The workmen admitted surveys were rarely done or not done properly years ago! The company did spend a few days sorting this, but would not consider the removal of the cwi. They also siliconed my cavity air bricks up, which were unlseeved.

    However, my initial joy that this may now be sorted did not last when I started to think of the years we had spent trying to sort this, along with the money we had wasted on attempting to resolve and the constant redecoration. We later had 2 more damp patches reappear (when the weather was wet) and disappear and we are not sure if this is still linked. The installers finished one month ago and I am allowing some time to see whether this has worked before I take the matter further with them. My experience seems similar to this posting on Premier Heritage : Carole17 September 2014 at 9:26 pm.

    I understand how people feel about this issue, it takes over and you feel that you have no one to turn to for decent advice. The reputable forums are a godsend to people trying to sort this out. Reading the forums I think some people have faired a lot worse than I have and so I should be thankful for that, however people obviously need help as some cannot deal with this on their own!. I will persevere with the installer and continue to follow this forum.

  27. E Bell 4 November 2014 at 3:52 pm permalink

    * sorry I stated RICS – “no RCS indepenpent seems to cover north east area but I do think an independent RICS surveyor, specialising in damp is helpful.”
    I meant to say “no PCA Independent Surveyor seems to cover north east area, but I do think an independent PCA surveyor specialising in damp is helpful.”

  28. Jo Robinson 6 November 2014 at 5:16 pm permalink

    Hi all we have a 1900’s ground floor flat and under the govt initiative had CWI in 2011. We have had mysterious damp patches growing in 3 rooms and have spent hours and many £ trying to resolve this one way or another. Finally we met an independent surveyor who put a camera in our walls where the damp was occuring and discovered that the property was not suitable in the first place due to the amount of rubble in the cavities. In fairness to the company who installed the CWI they were out to our property within 10 days and over the next 2 weeks cleared the debris. They were meant to finish the job tomorrow by refilling CWI so I decided to ask the surveyor to have another look to make sure they had done it correctly. Unfortunately his advice was not to have it filled yet as there was still patchy rubble, breaches of the cavity and large voids where the balls had . In his opinion refilling will just create further damp. I am thinking to ask the company to remove all of the insulation and not have it refilled. Any thoughts?

  29. E Bell 7 November 2014 at 10:34 am permalink

    I think I would consider the removal too. I have had the same experience, but without the guidance of your surveyor. The installers cleared the massive amounts of debris and repumped the wall to fill the voids. I am still experiencing problems and will have to recontact them. Sadly, although they try to help, I really don’t believe they are adequately qualified to understand the damage caused. If you make progress – please repost.

  30. graham R 15 January 2015 at 9:16 pm permalink

    Mighty problem with cavity wall insulation crap. People think just because this facility is approved by government it’s ok!
    Had this stuff pumped into my home – several years down the line it failed badly with damp patches all over the place. Did some investigative work and knocked out bricks to discover soggy pissed thru insulation stuff. Tried for compen but no joy, company reckoned it was my fault. Still suffering with this problem and continually trying to get rid of the damn stuff. Would never encourage anyone to have this cavity rubbish done to their home – it’s a con.

  31. Vicki Wallace 22 January 2015 at 10:23 am permalink

    I’m at disaster stage now. One of my rooms is completely inhabitable, smells strongly of damp!! And all over my bedroom furniture. And to top it offl I have 3kids in here too!!! Two of which have previous breathing difficulties. Luckily their room is fine and they’re never in the room and the door is shut at all times. Also this room is at the rear of my house. I don’t think my house is properly insulated as it’s always cold about half an hour after the Heatings off. After reading this I don’t think CWI is what I need!! Maybe just a good loft insulation?? There’s nothing up there, my boiler is in a box room. Help people?? Any advice??

  32. Claire Eades 22 January 2015 at 8:40 pm permalink

    A group of victims have set up CWIVA (cavity wall insulation Victims’Alliance) please find us on Twitter and Facebook. We are hoping to bring a debate to Parliament on 3/2/15 via MPs

  33. Brian j Davies 6 February 2015 at 12:50 pm permalink

    Athough minor at present, the damp migrating from the outside in my flat is slowly getting to be a problem. Is there anything that I can do? The cavity Wall Insulation is 3/4 years old.

  34. Stuart 7 February 2015 at 5:17 pm permalink

    Further thoughts and views. I am not a qualified surveyor or in the insulation trade but just spent time on the internet and speaking to damp proofing companies. Good relevant advice is actually really hard to find!
    British Gas have just surveyed my 1940’s bungalow property to ascertain if its suitable for CWI under the free Gov backed scheme. They drilled a number of external holes to check to see if CWI existed already.
    1. They didn’t use a camera to check for cavity bridging caused by rubble.
    2. They weren’t interested in even looking at new extension even though it was built in the 1980’s. Is this some sort of cost minimalisation on their part whilst still allowing then claim full expenses from the Gov Fund?
    3. They don’t mention or were put off by black mold in the front room on the inside wall (which is an external facing wall) and what is probably rising damp and I am advised by two separate damp treatment companies that damp course injection treatment is required on both the internal and external room to address this issue.
    4. British Gas have not provided me with any written information about what they intend to do or products to be use or and how its going to be done – on following up they have said that “they don’t normally provide any written information”.

    This is incredibly poor and appears to be the bare minimum to comply with the Gov insulation scheme rather than whats best for the building. I have no written visibility if they will fill the holes with mortar or silicon after filling or even put air brick sleeves into the walls to protect my suspended floor ventilation from being blocked by the CWI insulation dropping down.

    All in all, this appears to be totally inadequate and is a recipe for completely unregulated work not to appropriate standards being carried out.

    Before making any decisions,I strongly advise anyone insisting on a full survey report of all intended actions, materials and considerations made for any signs of condensation, rising or permeated damp, vents and also any risks associated with the particular state and location of the property.

    A building that is particularly dependent on ventilation through cavity walls may struggle to cope after treatment.

    I am probably going to cancel my CWI installation appointment!

  35. Claire Eades 15 February 2015 at 11:39 pm permalink

    Please find CWIVA It is imperative that everyone notifies their MP. The only way to shift policy.

  36. geoff hancock 19 February 2015 at 2:29 pm permalink

    even with clear cavities prior to filling west (WEATHER)facing walls now showing clear evidence of major problems .Fill is wet through .Moisture runs off down the cavity but shows through on all overhead window lintels .Also the timbers supporting the suspended floor at ground level are streaming with water as it descends to its lowest point .a complete disaster.

  37. duncan 12 March 2015 at 5:57 pm permalink

    Our Church had cavity wall fll installed in 2008 over the last 2 years we have been suffering extensive dampness inside the rooms. On recent investigation we found that the lead flashing over and along the top of the cavity is defective due to it being very thin and has many cracks across it. This has allowed rain water to penetrate down the cavity making the fill very wet. We realise that it will take a long period of time for the fill to dry out naturally so we are getting prices of firms to come and remove the fill once the lead problem has been dealt with. I would be interested to to hear from those who have had such removal work done. i.e. who did it , prices, and was everything done satisfactory. You can reply to me by email also on duncan3@hotmail.co.uk. I shall give a write up /feedback once our work has ben done. Duncan know

  38. Pauline Saunders 11 June 2015 at 7:19 pm permalink

    CIVALLI – Cavity Insulation Victims’ Alliance has been set up by Pauline Saunders (founding member of CWIVA) to carry on the great work providing free help to victims of botched cavity wall insulation

  39. Christina Ventrini 21 April 2016 at 11:30 pm permalink

    I was looking for feedback on the apparently waterproof injected beads that I am considering having injected into the cavity walls by Evolve.
    Lots of bad experiences here but I can only find one mention of this type of insulation used.
    Any further info would be greatly appreciated.

  40. June 10 May 2016 at 1:25 am permalink

    I was persuaded to have CWI beads in the cavity walls of my house. I was told by the installer that there was not any insulation there already. The house is 15 years old. The back wall became saturated and the mortar went black in large patches and a lintel was saturated dropping water into my conservatory.
    A surveyor has recently told me that there was already insulation boards that left a gap for air to circulate. This was done when the house was built. The insulation will be removed but this will leave me without the boards which kept my house warm enough. I cannot have those reinstalled now without removing the outer walls and installing it. How can I get my house back to what it was?

  41. Serge K 16 July 2016 at 6:19 pm permalink

    This article should more explicitly point out that most homes are suitable. A wall is unsuitable only if it has small eves, gets a lot of rain, and has crappy brick & mortar.

    There are a lot of double brick homes in dry Australia. And the climate would allow most to be filled. Who thought it was a good idea to build same style housing as in UK, i don’t know.

    Any single story house with a decent evens is ok. Double story in a wet place and crappy brick & mortar probably not.

    But most can and should be filled.

  42. Phil Beynon 27 July 2016 at 10:38 am permalink

    Hi Serge K.

    Your description of a property suitable for CWI seems a bit short on technical matters that are perhaps as important as the matters you mention; for example, cavity width, wind exposure, Finlock gutters, etc.

    Personally, never seen any suggestion concerning small eaves.

    Can you share your suitability reference document with us?

  43. Anne Whittaker 3 August 2016 at 3:03 pm permalink

    we had CWI from Government backed scheme about 5 years ago, we had some storm damage and because of the storm on one wall the rockwool insulation got wet, insurance sorted the internal damage, we paid for the roof to be sorted, they sent specialist drying equipment in and fans to dry the wall out, the specialist drying firm said the insulation would dry out but I was a bit dubious, the room felt cold all the time and even when they had removed the equipment I was getting 4 litres of water out with my dehumidifier in 24 hours, I rand Eagga who installed it, now sold to Carillion, they were very helpful, as it was still under guarantee they arranged for a survey and the removal of the CWI, they are here removing it now, found out the wall where the garage is wad rubble up to 6 ft then insulation on top… and where they have taken it out there were loads of the stuff that was wet, now I know why my rooms downstairs felt cold and why there was so much water coming out through dehumidifier
    I would never have any put in again, it has caused damp and even in one of my kitchen cupboards my stuff was going moldy, the dust is terrible and fluff blowing everywhere, be so glad when its all out they have been here 3 days already and will have to come back to replace my bricks

  44. Sue Rae 8 December 2016 at 12:22 am permalink

    Does anyone know if cavity wall products can be mixed together? I have sheets of one inch mineral wool in the cavity and I would like to fill the rest of the gap with beads. Anyone got any ideas if this will work as the one inch mineral wool is hopelessly inadequate
    Sue Rae

  45. Jon Billas Breaker 3 June 2017 at 9:43 pm permalink

    Most of your houses smell damp even with no cavity walls: Therefore the problem is not the cavity, it´s the bad way it is built using crap materials. So instead of complaining about the cavity have a look to your outside wall maybe it´s letting water going in. Of course living on a wet and cold zone your wall will be wet too one way or another so try to keep your house dry and ventilated. All your houses smell mold so it´s about time to remove all your carpets and use hygienic materials instead.

  46. Diana 21 June 2017 at 10:56 pm permalink

    Building a new house with extra wide cavities (200 maybe 250) and planning to use blown bead insulation or blown mineral wool but reading through this I’m wondering will I be creating damp problems for the line? Any advice?

  47. Svusan 12 December 2017 at 7:19 am permalink

    Think iive boobed. 1990s bungalow with cavity bead and glueu insulation added retrospectively. A builder added one airbrick to subfloor void after. He drilled through inner brickwork across cavity into inside. He did not use a sleeve and fitted an outer airbrick. I thought it was some of insulation which came out when he had inserted then pulled out a plastic tube he had used to ckeck hed got all way through. I am worried there has been loss of insulation aand that air can now enter cavity space .
    Am i correct that this could be problematic?
    He told me i worry too much and that hed added the airbrick correctly to aid subfloor ventilation as i had wanted. Any thoughts on this?

  48. Chris 30 December 2017 at 5:55 pm permalink

    We have been approached three times by people offering free CWI under government scheme. Each time I have told the salesman that we don’t want it because of well publicised problems and friends who have had problems. Each time they have told me we are only ones on our estate not to accept, I know that this is not true as I have spoken to neighbours – the last salesman came when only my wife was in and said it will be compulsory from next year for houses to have CWI installed and we will have to pay. These people are cowboys with targets to meet and are quite aggressive.