Damp Cavity Wall Insulation in Exposure Zones

Damp can occur in properties as a result of cavity wall insulation if one or more of the following conditions is present

your home is exposed to severe levels of wind-driven rain (zones three or four in the map below)

your home is located in an unsheltered position, e.g. not protected by trees or other buildings

the external walls are poorly built or maintained with, for example, cracks in the brickwork or rendering and / or defective mortar.

Homeworks is involved in a number of client engagements in the South and North West of England and along the Wales coastline where exposed properties have been insulated and are now experiencing very severe problems with damp. Homeworks are involved in extracting the damp cavity wall insulation.

If you or your property is located in a severe exposure zone and you are concerned about the state of the cavity wall insulation, please contact us.

Published guidance by the Building Research Establishment says that in these cases there is ‘an increased risk of rain penetration if a cavity is fully filled with insulation’. Rain could penetrate the outer wall, bridge the cavity via the insulation material and transfer moisture to internal walls, causing damp.

When Does Cavity Wall Insulation Need to Be Removed?

There are a variety of reasons why a property might need cavity wall extraction:

1) Slumping Insulation – Some of the earliest cavity wall insulation, employing more rudimentary materials, has now slumped in the cavity wall, leaving cold spots that may be causing condensation.

2) Urea Formaldehyde – This form of cavity wall insulation was used for a period of time in many thousands of installations. We now know that this degrades over time losing it’s insulation properties and in the process can present health risks due to gases which are released as it degrades and so the removal of this type of insulation is advised.

3) Poorly Installed – More recently, unfortunately, we see many cases of poorly installed cavity wall insulation where the wrong drill pattern or blowing pressure has left cold spots which may lead to condensation. Cavity wall insulation cannot be ‘topped up’ and so cavity wall extraction and correct re-installation is recommended. Other poor installation practices, such as not dealing with wall vents properly, can cause similar problems. You may have noticed that stories about poorly installed cavity wall insulation have been appearing more and more in the media. Keep an eye on our blog where we will be posting anything we see.

4) Flood/Water Damaged Insulation – Cavity wall insulation may have been damaged during flooding; sometimes broken or under performing rainwater goods may have allowed water to penetrate the cavity or the property may be located in an area of high exposure to wind driven rain. If cavity wall insulation becomes wet or damp, it really must be removed as this will transfer moisture to the inner skin of the property, damage wall finishes and potentially cause health hazards.

5) Unsuitable Building Type – the building, or a particular wall, may have been unsuitable for cavity wall insulation. Examples can be buildings with porous brickwork or mortar; steel and timber framed buildings; or buildings with high exposure to moisture.

6) Steel Framed Properties – We have had a few cases lately where we have been asked to carry out Extraction on Steel Framed properties. In all cases the customers have been trying to sell their properties but have found that potential buyers have been turned down for the mortgage due to the fact the property is insulated.

Cavity wall insulation is not recommended for steel framed houses because they need a well ventilated cavity to prevent moisture from building up and corroding the steel.

If insulation were to get damp it would hold the moisture against the steel frame, particularly towards the bottom of the structure and make it more likely to corrode.

In the majority of cases steel framed properties should not have been insulated in the first place.

If you find yourself in this situation fear not, all is not lost. The property can be Extracted.

The time and cost of cavity wall extraction depends entirely on the conditions that present themselves: the size of the property, the nature of the cavity wall and, of course, the material that must be extracted. It is difficult therefore to provide an indication of cost without gaining some more information about the particular job in question. However, we have tried to answer some questions about the cost of cavity wall insulation extraction here.

If you think you may need our cavity wall extraction services, please contact us for a discussion about your particular project and we will work alongside you to find the best solution to your cavity wall insulation problem.

Why Steel or Timber Framed Properties Should Not Be Insulated with Cavity Wall Insulation

Steel and timber-framed houses should not be insulated with cavity wall insulation. However, few people seem to understand why.

Timber and, surprisingly to many, steel, both need air circulation to prevent rot or corrosion. Many of us will live in houses that have suspended timber floors, and will be aware of the air bricks strategically laid at damp proof course height. These air bricks allow air to circulate underneath the floor joists preventing rot developing and keeping the timbers healthy. The same practice is required inside the cavities of timber and steel-framed houses. Fully insulating the cavity with a retro blown cavity wall insulation product increases the risk of condensation forming and being trapped against the frame. With timber framing, this might lead to wood rot; with steel it will result in corrosion.

There are, thankfully, other ways to insulate a timber or steel framed property very effectively. External wall insulation, for instance, is extremely effective. Internal wall insulation is another option to consider.

If you live in a timber of steel framed property that has been insulated with cavity wall insulation, you will need to have it removed. Over time it may lead to serious structural damage. If you have any further questions and require advice, please do not hesitate to contact us.

Why Does Rubble in A Cavity Wall Cause Problems?

Among many other things that a surveyor will be looking out for, cavity wall insulation requires a clean cavity. Filling the cavity with insulation can cause damp if not installed correctly and this is often due to lumps of mortar (known in the trade as ‘snots’) lying at the foot of the cavity wall on the cavity ties.

As the wall was built it is possible that mortar fell in the cavity and came to rest on the ties. The problem is that rainwater hits the external skin and penetrates to the snot sitting on the tie. That is not a problem in an open cavity as the ventilation will dry any moisture penetration before it reaches the inner skin.

Filling the cavity with insulation will reduce the  ventilation. The rainwater will still hit the external skin and penetrate to the snot but now cannot be evaporated away and continues to penetrate to the inner skin and emerges as a damp spot.

A good surveyor will check that your cavity wall is clean before filling it with insulation. Reputable insulation companies will do this for you as a matter of routine and give you an honest answer. Unfortunately, we know that many cavity walls that contain rubble and mortar snots have been insulated. This has, or will, likely contribute to penetrative damp and further problems in time. In this situation, the cavity wall insulation will need to be removed.

Our thermal imaging service is a useful tool to establish whether or not a cavity wall is being compromised by the presence of rubble and mortar snots. Please contact us for more information or to arrange a free survey.

When Are Properties Unsuitable for Cavity Wall Insulation?

We regularly come across properties that are unsuitable for cavity wall insulation. The following list comprises the most common reasons but it not intended to be exhaustive:

  • Properties with elevations that are particularly exposed and susceptible to wind driven rain
  • Timber framed properties
  • Steel framed properties
  • System built properties
  • Properties with defective rainwater goods and/or unlined finlock guttering
  • Properties where there are significant areas of perished mortar (require re-pointing) or masonry
  • Properties that are experiencing issues with penetrative damp
  • Properties without a DPC, or where the DPC is too low (typically less than 125mm from the ground) and a French drain has not been installed
  • Some properties with raked mortar joints
  • Properties with a cavity wall under 40mm or over 150mm
  • Properties that have significant rubble or mortar ingress in the cavity

We are regularly called to survey properties that exhibit these characteristics but have been filled with cavity wall insulation. The outcome is often that it has become damp and is now causing a range of further problems. In this situation, it is almost certain that the cavity wall insulation will need to be extracted. Click here to find out how but please contact us if you are unsure.

What to Do If You Think You Have Problems with Cavity Wall Insulation

We are often asked what to do if you suspect that cavity wall insulation might be causing damp or other problems in your property. The answer, initially at least, is quite simple. There are three simple steps:

Firstly, contact the company who installed the cavity wall insulation and discuss it with them. Ask them to come and look at the problem and take a sample of the cavity wall insulation to establish whether it is wet. If it is, they should be able to indicate why and arrange for extraction if required.

Secondly, if the installer if unhelpful or no longer operates, contact CIGA to establish whether or not you have an industry standard 25 year CIGA Guarantee. If you do, they will be able to help you further and you may be able to resolve the problems under the terms of the guarantee.

Thirdly, if you do not have a guarantee or CIGA are unable to help, please contact Homeworks who will be able to help. We are one of the UK’s leading specialists in problems associated with cavity wall insulation. At the very least we will be able to offer advice and point you in the right direction. If appropriate, you may want us to survey your property to establish how to put the problem right. This may involve removing the cavity wall insulation.

So, remember, if you have a problem with CWI, go to your installer in the first instance, try CIGA next and, if you still need help, please pick up the phone to us.

Problems with Wet Cavity Wall Insulation Explained

We have re-published the following article that Ben Craig, Managing Director of Homeworks issued last year because we are aware that it has been widely read. We hope that it is of interest if you are experiencing problems with damp caused by cavity wall insulation. If you are in any doubt or would like a survey to clarify the cause of the problem, please do not hesitate to contact our specialist cavity wall extraction team on 01926 831851.

Do you have problems with damp cavity walls?

“We are being increasingly contacted by customers who are having issues with cavity wall insulation damp or condensation and wondering how best to solve them. It is not only solid wall properties that can suffer from condensation and damp penetration. If cavity wall insulation is badly fitted or gets wet it can cause a huge number of problems.” Homeworks Director Ben Craig

Condensation on Cavity Walls

Condensation on cavity walls often presents itself as black mould spots and is caused by the warm air inside the house condensing on cold wall areas. If cavity walls are filled properly by a reputable company you should not be experiencing this problem however there are a couple of cases in which this can happen:

Firstly some of the earliest cavity wall insulation, installed over 25 years ago and employing more rudimentary materials, may have slumped in the cavity wall, leaving cold spots that may be causing cavity wall condensation.

More recently, unfortunately, we see many cases of poorly installed cavity wall insulation where the wrong drill pattern or blowing pressure has left void spots which may lead to condensation.

We have also heard of shameful practices where cavity walls have been drilled but not one fibre of insulation is installed as the company is only interested in making a quick profit. As the industry is not regulated with invasive drilling there has so far been no way of checking if this has happened.

Damp Cavity Walls

Damp in cavity walls is noticeable as the internal plaster finish will start to blister and crumble as the moisture content rises. There are a number of causes for this:

Cavity wall insulation may have been damaged during flooding. After the winter we have just had this is a common occurrence.

Sometimes broken or poorly performing rainwater goods may have allowed water to penetrate the cavity.

The property may be located in an area of high exposure to wind driven rain and standard cavity wall insulation should not have been installed in the first place.

In cases of cavity wall condensation or damp  the only real course of action is to have the cavity wall extraction, and if suitable re-filled. Homeworks are specialists in this field, and we will survey and advise you of the best course of action. Please contact us to find or visit: cavity wall insulation extraction.

Cavity Wall Insulation and Damp

Do you have problems with damp cavity walls?

“We are being increasingly contacted by customers who are having issues with cavity wall insulation damp or condensation and wondering how best to solve them. It is not only solid wall properties that can suffer from condensation and damp penetration. If cavity wall insulation is badly fitted or gets wet it can cause a huge number of problems.” Homeworks Director Ben Craig

Condensation on Cavity Walls

Condensation on cavity walls often presents itself as black mould spots and is caused by the warm air inside the house condensing on cold wall areas. If cavity walls are filled properly by a reputable company you should not be experiencing this problem however there are a couple of cases in which this can happen:

Firstly some of the earliest cavity wall insulation, installed over 25 years ago and employing more rudimentary materials, may have slumped in the cavity wall, leaving cold spots that may be causing cavity wall condensation.

More recently, unfortunately, we see many cases of poorly installed cavity wall insulation where the wrong drill pattern or blowing pressure has left void spots which may lead to condensation.

We have also heard of shameful practices where cavity walls have been drilled but not one fibre of insulation is installed as the company is only interested in making a quick profit. As the industry is not regulated with invasive drilling there has so far been no way of checking if this has happened.

Damp Cavity Walls

Damp in cavity walls is noticeable as the internal plaster finish will start to blister and crumble as the moisture content rises. There are a number of causes for this:

Cavity wall insulation may have been damaged during flooding. After the winter we have just had this is a common occurrence.

Sometimes broken or poorly performing rainwater goods may have allowed water to penetrate the cavity.

The property may be located in an area of high exposure to wind driven rain and standard cavity wall insulation should not have been installed in the first place.

In cases of cavity wall condensation or damp  the only real course of action is to have the cavity wall extraction, and if suitable re-filled. Homeworks are specialists in this field, and we will survey and advise you of the best course of action. Please contact us to find or visit: cavity wall insulation extraction.

Your CIGA guarantee may be effective in these circumstances and you should check your guarantee as soon as possible, as if it is left without being treated, it could end up a lot more expensive for you and your health.

If you’ve got issues of any other nature with your Cavity Wall Insulation that may be down to the installer not following proper guidelines as to the install. It is now apparent that hundreds of thousands of home owners across the UK will need remedial work that will consist of a full extraction of the Cavity Wall Insulation and could well mean a whole host of other repairs and replacements directly caused by the install.

Contact Wall Cavity Claims today on free phone 0800-8-654321 or visit www.wallcavityclaims.co.uk

2 Comments

  • Graham Wills

    This article is written by a Council Member of CIGA – in fact all of CIGA’s Council Members have their fingers in the cavity wall insulation pie (maunfacturers, installers and now extracters. I think it’s a bit rich for him to tell you this after your house has been ruined. You should have been told before it was installed – they knew all about it, but through greed they kept the facts secret. It was all covered by Building Regs. – This stinks!!

  • Wall Cavity Claims

    Hi. Our articles are written by our own researchers who have been helping those affected by CWI failure for almost 4 years. The market is evolving and we aren’t in anyone’s favour only our clients. Chartered Surveyors carry out independent surveys and where a fault lies with a third party it will be identified in these reports.

    Noone at our company has any involvement with CIGA or the council. We have no interests in any installer firm or extraction firm.

    Our priority is for clients across England & Wales who have damage in their homes and they need help and support how to get things put right.

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