Why get cavity wall insulation?
A home can lose as much as 35% of its heat through uninsulated external walls. By investing in cavity wall insulation, you can significantly reduce the heat loss from your home. The concept of insulating a cavity wall is really very simple – it involves filling the cavity between the two skins of masonry bricks with an insulating material, which slows the movement of heat through the wall. Maintaining the heat inside your home keeps you warm and cosy when you need to be. It also works in reverse by keeping your house cooler in the summer months.
Installing cavity wall insulation in your home will not only help to decrease your heating bills by saving energy lost through the walls, it will also help to reduce your carbon footprint by limiting the amount of CO² and other greenhouse gases emitted from your property.
Many houses since the late 1930s were built with a cavity between the inner and outer walls. Because of this cavity, many of Britain’s homes have thermal performances which are well below the standards required by current building regulations. These properties suffer from unacceptably high levels of heat and energy loss through the walls. A system was introduced in the 1970s to inject insulation into these cavity walls.
Can I get cavity wall insulation?
There are two things you need to determine to see whether you can benefit from retrofitting cavity wall insulation in your home.
The first thing is to work out if you actually have cavity walls – this might seem stupid, but you can not inject insulation if there isn’t a cavity and they do look quite similar to solid walls!
A cavity wall is made up of two masonry brick walls running parallel to one another with a space (cavity) between them of at least 50mm. Masonry bricks are very absorbent, so moisture absorbed by the outer wall typically drains through the cavity, rather than coming into the home, helping to prevent damp issues. This type of wall construction became the norm in the 1930s superseding solid walls and as time has gone on, the size of the cavity between the two skins of brick has continued to grow – a typical cavity wall now is between 280-300mm thick.
You can easily identify a cavity wall by the pattern produced by the brickwork, which is known as stretcher bond, where are the bricks are running in the same direction as one another – there are no ‘half bricks’. This is obviously harder to do if your walls are cladded or painted and in this case you might need to call in a professional (although sometimes you can see original brickwork in the loft space). In addition cavity walls tend to be over 250mm in width, with more recent cavity walls closer to 300mm. If you can see lots of half bricks in your wall, you have a solid wall with no cavity, so unfortunately cavity wall insulation is a no-go. In this case, you could look into external wall insulation as an alternative.
Once you have established that you have cavity walls, you need to determine the size of the cavity and whether it has previously been insulated. A registered installer will need to come and carry out a boroscope inspection. This involves drilling a test hole into the wall and checking with a camera to see if the cavity has previously been filled and the size of the cavity (ideally over 50mm). If this shows the cavity is unfilled, you could indeed benefit from cavity wall insulation.
Although some builders began insulating cavity walls in the late 1970s, it only became compulsory under building regulations to do so during the 90s. As such there are many properties in the UK that currently have unfilled cavity walls. The good news it that these can be insulated very easily!
How does cavity wall insulation work?
If a hot room is partitioned from the cold by a wall, heat will move through the wall, eventually cooling the room until an equilibrium is reached, where the outside temperature is equal to the inside temperature. In reality this very rarely happens, because rooms tend to be heated. This means that as some heat escapes through the wall, more hot air is supplied, keeping it at a comfortable ambient temperature. If the thermal gradient is larger, (e.g. on a cold and wintry day), the movement of thermal energy across the wall will be accelerated.
Insulating a cavity wall helps to provide a thermal barrier, which slows the flow of heat out of a room considerably. By slowing down the rate at which heat escapes from the home, less heating is needed to keep the house at the required temperature. In the summer, the reverse happens; hot air outside the home can’t get in as easily, which means you don’t need to use energy to keep the home cool. Therefore in both summer and winter, cavity wall insulation can make an enormous difference to your energy bills. The process is relatively quick and inexpensive, so it is certainly worth considering.
How do you insulate cavity walls?
The first thing to note is that you cannot retrofit cavity wall insulation as a do-it-yourself job – it is a job that needs to be carried out by a professional.
Once the cavity has been confirmed by the boroscopic inspection, the installer will drill a series of 22mm diameter holes into the mortar between the bricks. With specialist equipment, the installer will then inject the cavity with the insulating material, through each of these holes. Once the whole of the cavity wall has been filled, the mortar will be made good either with plugs or mortar created to match the existing colour, so the job will be barely noticeable.
The insulating material pumped into the cavity is normally a type of glass wool, or in some instances insulating beads and once installed will offer insulation for the life of the building. The whole process should only take about 2 hours but obviously if the cavity wall area is especially large you will need to leave more time for the job to be completed.
What materials are used for cavity wall insulation?
Expanded polystyrene (EPS) foam, loose polystyrene beads, or wool. EPS is the most expensive option for a reason; it is a premium product and we would always recommend spending the extra money for the best results.
Savings from cavity wall insulation
Although the savings from cavity wall insulation vary greatly from property to property, for an average size three bedroom home, the energy savings from installing cavity wall insulation should amount to £250 per year. With an installation cost of £600-1000, the savings you create from installing the cavity wall insulation should pay for the work in under 4 years.
Getting cavity wall insulation in the Green Homes Grant
If you are eligible, you can now get a grant of up to £10,000, using the Green Homes Grant scheme. The grants are available until March 2022 and are being offered to properties in England.
There are two grants within the Green Homes Grant. First is the £5000 which most are eligible for if they have cavity walls. However, if you are receiving one of the below benefits, then you may be eligible for the £10,000 grant.
- Income Support
- Income-Based Jobseeker’s Allowance (JSA)
- Income-Based Employment and Support Allowance (ESA)
- Universal Credit
- Pension Guarantee Credit (excluding Pension Savings Credit)
- Child Tax Credit
- Working Tax Credit
- Disability Living Allowance
- Personal Independence Payment (PIP)
- Attendance Allowance
- Carer’s Allowance
- Severe Disablement Allowance
- Industrial Injuries Disablement Benefits
- Contribution-Based Jobseeker’s Allowance (JSA)
- Contribution-Based Employment and Support Allowance (ESA)
- Housing Benefit
If you are interested in the Green Homes Grant, we advise you look at the Government website.
Paying for cavity wall insulation yourself
Unfortunately schemes like the Green Deal have now finished, but the Green Homes Grant is still available for cavity wall insulation.
If you are interested in getting cavity wall insulation installed, we work in partnership with EWI Store who have a network of approved installers. So please fill in the form at the bottom of this page, and we will be in contact with you shortly.
Benefits
- Insulating your cavity walls will help you to heat your home more efficiently, saving about £250 for a typical 3 bed home.
- Cavity wall insulation will payback in 3 – 4 years for the investment giving lower heating bills .
- According to the Energy Saving Trust, cavity wall installation can reduce carbon dioxide emissions (CO2) by 560kg, according to the Energy Saving Trust.
- Approved cavity wall installation work is guaranteed for 25 years by the CIGA (Cavity Insulation Guarantee Agency).
Limitations
- Cavity wall insulation may not be suitable within your home, if it has a wall exposed to strong rainy wind.
- Do not undertake the installation if the home suffers from damp problems – seek an assessment from a professional surveyor first
Cost
- Cavity wall insulation can cost anywhere between £600 – 1000 (however with subsidies, the cost may end up at the lower end of this estimate – speak to your Energy provider).
Installing Cavity Wall Insulation
Need cavity wall insulation? We have scoured the country for the best tradespeople, so that we can make sure we only recommend those we really trust.
If you would like us to find you a local insulation installer, just fill in the form below and we will be in touch shortly!
Hi would like to know more about my options for cavity wall insulation thanks
The point about driving rain is a good one. However, the idea that the property is then not suitable for cavity wall insulation is incorrect – it just means a more appropriate type of cavity wall insulation is required – check out Technitherm from Isothane for this type of location and for flood risk areas.
can i get free cavity wall insulation if im with housing association
Quite possibly – worth ringing the housing association and asking the question. Cavity wall insulation is one of the cheapest energy efficiency measures available and so the Government / councils are very keen to get this installed so you might be in luck!
hi,
we live in an old railway house. the walls are about 21 inches thick, 4 bricks deep, but they do have a cavity between the exterior and interior walls. the house was built in 1908 but I have been informed that cavity wall insulation can’t be installed as the house is too old for cavity walls……basically they don’t want to do the job.
do you reckon I’m being fed a bit (copious amounts) of male bovine manure?
Hi Jon, as a rule of thumb installers are taught anything built prior to 1935 is solid wall construction while anything built after this is cavity wall – it is for this reason that they don’t view your walls as a true cavity. In a way they have a point as the cavity is likely to be filled with all sort of rubble which will hamper the cavity wall insulation process. It is for this reason that I wouldn’t suggest going for cavity wall insulation as it might lead to damp issues down the line, however if you are going to go for it, I would ensure you go for the beads rather than the wool to help minimise the risks.
I have a ground floor flat which is 28 years old. I suffer from mould in 1 corner of my bedroom and this room is extremely cold at times. I need to keep the heating at a constant temperature for my sick husband. Despite treating the corner where the mould is it keeps recurring between the fitted wardrobe and the outer wall, spreading under the drawers. I have been told that it is caused by the cold outer wall and the warm inner one. Would cavity wall insulation fix this? My neighbours also want this if there is some sort of grant available. I have also been advised that a dividing ‘brush’ can be fitted to separate any flat that does not want the work carried out.
Also we live quite near the river mersey and when the weather is bad the rain can come in sideways! What is the difference from Technitherm to Isotherm? Would appreciate your help
Hi. Just wondered if I could get some well needed advice . I have damaged cavities which are full of mortar and not suitable for cavity wall insulation and have recently paid to have rockwool removed and new wall ties . I have been told by a local energy company that external wall insulation would be next best option , at a cost of £ 12-1500.(detached property ) my builder who has undertaken renovation works states that internal would be better(as most possibly he is happy to fit this – I am maybe being cynical). This was the same guy who told me I could replace rockwool removed with thermabeads until energy firm came out and said to the contrary . I am so confused and nedd to make a decision .I will have to borrow money for external wall insulation but dont mind as long as this is the right thing to do and will save me money on bills and keeep housr warm. Please help
(April 2022) I’ve just been speaking to a helpful external wall insulation specialists who advised me that if I externally insulate without closing the cavity, I’m effectively insulating the cold void of the cavity without adding much thermal benefit to the inner leaf. That assumes that there is substantial air movement within the cavity and contradicts James Alcock’s answer to the question below which suggests that there’s relatively little convection within the cavity, so I am a bit puzzled. I think the advice I got is correct if the cavity is ventilated and James’ is right if the cavity is well sealed. So it’s not a simple answer.
Excuse me
I have a question
Why can’t I only use air gap instead of any insulation material in a wall??? (Explain in details)
The air gap reduces heat losses from the walls by both conduction and convection: conduction, because heat can’t conduct through gases; convection, because there’s relatively little air between the walls and it’s sealed in, so convection currents can’t really circulate. That makes cavity walls a bit more efficient that solid walls and therefore as such have a marginally smaller u-value.
In truth though, we need to try to stop heat escaping completely (or at least slowing the rate at which equilibrium is met either side of the wall) therefore by using a really good insulator (mineral wool / PIR board) then this is going to have a far bigger impact on heat loss than having unfilled cavities.
Sorry about putting this in as a plug, but as you have talked about PAYING for wall cavity insulation I thought I should point out you can have this installation for free. ECO Contracting Services will do the technical survey and installation for free under the Governments Eco scheme. Im part of the sales team, we send technical surveyor’s to the property to do a EPC and talk to the customer about which insulation would be best suitable for the property (this can include free loft insulation).
Hi, I was wondering if you could provide me with some assistance. We had someone knock on the door offering free cavity wall insulation. It is not something I had considered previously, but since it is free I thought I would do some research. Having looked online, cavity wall insulation has very mixed reviews, my house is cold during the winter months so I think it could do with the additional insulation however I don’t want it to lead to any damp issues. I live in Leicester (about the most famous place on the planet after the football this weekend!!) so there is no reported driving rain and the property was built in 1970 so I am guessing the cavity walls are a reasonable thickness, my understanding is that over time the cavity has got thicker. So how do I know if my property is suitable? It is semidetached and from I have asked my neighbours either side and one has had it done and one has refused so far. I assume the cavity wall insulation companies get paid to install it so couldn’t really give a damn about whether it is truly suitable or not but obviously it is my home so I want to make the correct decision. Any thoughts on whether I should get cavity wall insulation would be greatly appreciated!
Avoid at all costs! Cavity wall insulation has made my house damp.
Hi Lisa, where abouts are you based? Cavity wall insulation when installed correctly is a brilliant energy saving solution – however there are cases where it is not worth installing cavity wall insulation and solid wall insulation should be installed instead (on the cavity walls). Solid wall insulation prevents winter ingress, so if you live in areas of driving rain this is the preferable solution.
Hi Susan, a very interesting comment and I would of thought a sentiment shared by many – is cavity wall insulation safe to install on my home? Well the answer really depends as the research you have carried out suggests. In many cases cavity wall insulation is incredibly effective energy saving measure – again as you mentioned there are companies still offering this for free and the impact on energy bills can be huge. Having said that, it isn’t suitable for every property – when cavity wall properties were built originally (to replace the older solid wall properties), the sole purpose of the cavity wall was to help prevent water crossing the wall into the home. As such, filling the cavity with insulation could make pathways across the cavity by which water can pass from the outer leaf to the inner leaf. Nowadays though the cavity definitely has two functions – the first is to prevent water crossing the wall structure but also the cavity is used to house insulation. I think it comes down to a few simple things – firstly it is important the right insulation product is used (wool or blown beads). Secondly there are some places where cavity wall insulation just ins’t suitable. If you have a property at the top of a hill or on the West coast then cavity wall insulation should also be avoided because of the risk of driving rain. Also (and this is the hardest to judge) not all cavity wall installers are great at what they do. If the cavity is not filled correctly then it will lead to cold spots in the house, also there are companies that inject the cavities and fill flues and vents which obviously should not be filled. I would always try to get a recommendation (so speak to previous customers that the cavity wall installer has used) – sorry to not be any more help!
Hi, I live in a semi built in 1982. When built, can you tell me if the cavity would normally flow through to next door or would it have been blocked where the two properties join?
Hi, they normally will put down cavity brushes into the cavity where there is a risk of the insulation flowing down into adjacent properties. This ensures the cavity wall insulation stays exactly where required.
Hello, i have recently bough a timber frame house, in newcastle as is around 35 years old, however when i bought the property they had removed the cavity insulation because they had to certoficates, should i be looking at getting it reinstalled? I understand that a dofferent type of jInsulatoon is required for this build type. Also if i have jt done would i Also be fIlling my Neigblurs walls? (Mid terrace) thanks
Hi Phillip, there are currently no cavity wall insulation materials suitable for timber frame properties (hence the need to remove it from your property). We have heard there is going to be a material released soon that is suitable but this is still going through final testing, but hopefully it will be released at some point during 2017.
We have had an assessment on our walls and been told we have a very thin cavity, so I am wondering whether it is worth / possible to insulate this? The assessor predicted it was under 45mm, so I am not sure what the potential energy savings would be but also I am aware that cavity wall insulation in some cases can cause damp, although we are located in near Reading and from what I have heard damp often happens in areas of high exposure. If we did end up insulating the cavity what is the product that offers the best thermal performance.
Hi Jimmy, my thoughts are that yes – regardless of the depth of the cavity, some insulation is better than none! In terms of cavity wall insulation failure rate, the numbers are actually pretty small and as you correctly point out, the failures tend to be far more concentrated in high exposure areas. For narrow cavities we would recommend going for the EPS beads (bonded), as these offer really good thermal insulation (for the thickness) compared to wool insulation products. It also creates a barrier, preventing water cross from the outer skin to the inner skin of brick so I would recommend looking to that as your best bet.
I am interested in getting cavity wall insulation installed on my 1980s semi detached house. The house is generally cold so I am looking for a cost effective way of improving this situation! I have been trying to research cavity wall insulation online, but specifically I am trying to find out which of the insulation products is the best to get installed in the cavity, From what I have read I have 3 options, foam, wool or EPS beads. Please can you let me know which is the best product to go for in terms of stopping damp entering but also providing the best level of insulation in the house. Would appreciate any help!
Hi Applemaid, we would always suggest bead to be honest, you will pay slightly more than you would for wool, but it produces a waterproof barrier within the cavity, so water cannot travel through it which means there is no danger of getting damp in the home. In addition this type of insulation has higher insulating properties than wool so therefore in our opinion it is the winner!
Thanks for all this info, it is very useful!
I have a question regarding cavity wall insulation. We have been offered two types of free cavity wall insulation for our 1970s mid terrace property. The first is a bead, and the other is wool, both of which are injected. My question is pretty simple really, which one should I go for! Since they are both free it doesn’t make much difference for me, but I guess like with all things there are good and bad products. I have read some horror stories about cavity wall; insulation, but my neighbours on either side have both had it done so I am happy that we are not in an area where the insulation would pose a risk on my home.
I guess since the insulation is hidden there are two things that are going to impact me, firstly the energy savings. I want to maximise these cause why not! Secondly, I want to minimise the risks associated with cavity wall insulation which as far as I can see is damp. So which will save me more and which is better at stopping damp crossing the cavity? Hopefully the answer to both of these questions is the same material!!
Thanks for help in advance
Alex
I was wondering how does cavity wall insulation compare with external wall insulation from a u value rating?
Hi Jonathan, this depends on the thickness of the cavity (as this limits the amount of insulation that can be used). If you are insulating externally, you tend to use a minimum of 90mm of EPS (expanded polystyrene). This will take the u-value of the solid wall down to 0.3 which on a retrofit would confirm with building regs. Over the years the cavity on cavity walls has been made thicker and thicker since its function moved from just preventing water ingress to doing that as well as housing insulation, but older cavities tend to be anywhere from 40mm – 60mm. If you insulate the cavity with EPS beads, you should expect to achieve a u-value of 0.45. Basically solid wall insulation is better in terms of energy saving, because the amount of insulation you can add is unlimited. The issue is that solid wall insulation is far more expensive than cavity wall insulation.
obviously on the thickness of the insulation when talking about
I want to get free cavity wall insulation and have heard there are government grants now available. Is this the case? Thanks. Mary.
Hi Mary,
There is a grant currently available called ECO. If you head over to our installer map, most (sadly not all) have access to this grant so put in your postcode to find your closest installer and then give them a call!
Click here to head to our map!
We are interested in getting cavity wall insulation in our block of flats. Is there a grant to help cover the cost of this? We know the neighbouring block have had it done, but I went outside the property and couldn’t see the little holes in the wall that I could see on the other block. It also gets extremely cold in the winter suggesting their is no cavity wall insulation. Will companies charge for an inspection to determine whether we can get this done.
I live in a bungalow in Oxford. I had cavity wall insulation installed in the walls of my home 22 years ago and I am wondering whether it is worth replacing? I am assuming the type of insulation is now better than what has previously been available and the home will be kept even warmer. Is this the case? Also we have noticed that our dining room is slightly cooler now during the winter months, can cavity wall insulation slip within the cavity. I don’t suppose it can as I guess it would have no where to go, but it would be useful to find out. Also we are now on pension credit, is there a grant available for the cavity wall insulation if we do end up getting it replaced?
Hi Arthur,
In truth the insulation materials haven’t really changed in terms of thermal performance. You might get marginally better performance from modern insulation materials, but only marginal! There is a chance if you had your home done 22 years ago, it was done with Urea Formaldehyde – this does break down over time and can slip down the cavity. It can be removed and replaced with new cavity wall insulation, but the issue is that it will be expensive to remove and there is no funding for that (you are looking at between £15 – £25 per m2 to get this done depending where in the country you are looking to get this done and accessibility issues). In terms of replacing with new insulation, there should be some funding available once the cavity has been cleared, but how much will depend on the funder / installer in your area.
I was offered free cavity wall insulation by a door to door sales guy last year. After several surveys and a whole lot of calls back and forth I never got anything done. I think if you want something like this done you need to pay for it. Grants seem to attract the wrong type of companies in my humble opinion.
Anyway I paid for it and got it installed this winter by a bead insulation company. They got it done within a week fo calling and it cost me just under a grand. Its a big detached house so I thought that was pretty reasonable. No problems as yet and I don;t expect there to be any. Don’t get these free insulation cowboys out – dig into your wallet and get the pros in!
Hi Jim, while I agree with you that workmanship is everything, there are companies out there that work with Government schemes like ECO that offer a quality installation. I think, negative newspaper headlines from the Daily Mail and the Express with respect to the cavity wall insulation schemes do not help. So, many in the public are turned off by problem stories surfacing as a result of poor workmanship, but then those same newspapers do not devote any time to actually cover the positive aspects of insulating your property.
I am sorry that you couldn’t benefit from any grant funding for the cavity wall insulation, but pleased you managed to get the cavity walls insulated and are benefiting from reduced energy bills this year! Just out of interest did the cavity wall insulation company provide a third party warranty with the installation as well?
Nick,
Thanks for your reply. Perhaps there are some exaggerated stories out there, but I think my experience shows that there is no smoke without fire. I hope that the government put some better controls in place to make sure these installers do a good job – and dont waste time with surveys that go no where – that would be my advice.
I think I got a warranty on my job, I will have to try and dig it out. Is this something they are supposed to provide? Ive never really been one for warranties mind. You can pay hundreds of pounds for a piece of paper – don;t tell me these companies turn up 10 years down the line when my walls get wet! That’s why I went for beads – get the job done right the first time, thats what I always say.
The polystyrene beads are a great insulant for the cavity walls and given you have gone for this option, I don’t think you can go wrong in terms of the superior thermal retention properties. However, I would go an cite a couple of reasons, why a private contractor with no certification may lead to problems vs. an installer that has been certified with a known competency scheme and would usually be listed on a Government approved website.
1. The Government approved and certified contractor would have to jump through a serious of hoops, and as mentioned would be certified externally for competence. Whereas the private contractor is unregulated.
2. Any funded jobs now via ECO or a Government backed subsidy scheme have to be surveyed and logged in a central database to prove they are suitable for the measure.
3. By installing as part of a Government funding scheme you are obliged to provide an external warranty, such as CIGA or GDGC, so if something went wrong with the installation, you would have the first steps available to claim on the install to have it re-mediated.
On the otherhand, you may well have had a very competent installer, and it is very difficult to judge standing here, purely answering back to your comments. Can I just ask what is the finish of your existing walls? Do you have brick or existing render?
Is cavity wall insulation safe? I have seen that dreadful fire in London and I am now wondering if we are at risk. We had cavity wall insulation put in 2 years ago. Thanks for your help.
Hi Norman, with regards to the the news over the last 24 hours – it is absolutely tragic, our deepest sympathies go to all those affected in North West London. In answer to your question, there are three products that tend to be used in cavity wall insulation mineral wool, polystyrene beads, or foamed insulants. Nowadays the most common material is the mineral wool as it is the cheapest to install. It is likely if you property was installed with cavity wall insulation in the last 2 years, white wool was injected into the cavity (if it was done under a Government scheme). To be honest with any type of cavity wall insulation you are safe – it would be very very unlikely to accelerate a fire since the insulation is contained within 2 skins of brick. If it is wool specifically the risk is even smaller as most wool are classed ‘Class A1’ in terms of their fire risk and A1 is essentially non combustable.
I live in a house which is only 2 years old. It’s very energy efficient. However I’ve been offered free cavity insulation. They say it will improve the efficiency even more. Would it cause damp problems and is it really necessary?
I live in a Danish built house, with well insulated weatherproof external walls. We also have a Bradstone block wall,made of 5 “re-con concrete blocks–which is not structural at all, just cosmetic.
My question is if I wanted to improve the insulation, would it be worth using cavity fill insulation, and ould it be safe to do so ???
I should like to install insulation in a property in Exmouth Devon.
1. How do I find out whether it needs doing or has already been done
2. I would prefer a local based contractor, rather than a national one
Thank you
We are having real trouble finding anyone to do the job in Oxford. Happy to pay since there are no grands for us. Problem is our concrete build 1950s house – there is a cavity, many people on the street had it done few years ago but now no one wants go give us guarantee.
Can you have cavity wall insulation in our 20year old bungalow that was built with therma blocks on the inside and will it benefit us
hi our bungalow had eps bead insulatin fitted about 10 years ago. Recently we added an airbrick to one ene of gable end. Lots of white grainy substance flowed out following removal of visual inspection pipe of subfloor void whilst airbrick being fitted. Further visual telescopic check showed no insulation inside this part of wall. Airbrick placed in situ into subfloor void without a liner through cavity. Should we be concerned about any future problems within cavity wall further along the gable end as we do know eps beads were installed to the gable end wall.
wold this white grainy substance have been froma thermablock or similar ??
Hi
Had mineral cavity wall insulation installed to our detached bungalow of 1990’s build, Following installation in 2008 there was a small void identified towards the bottom of side end wall. It is a detached bungalow of 1990’s build. In summer the heat can be seen coming off the external brickwork.. The small void was retrofilled but we were asked if it was a solid subfloor. We thought not but subsequently have been told although we have a subfloor void it would be classed as a solid floor. Would this affect the installation in any way and should we inform the company or not that filled the small void of about 1m square.
hi, my daughter is having problems with her cavity wall insulation. she has rain coming in threw her walls. she has been advised by a builder to have it removed,he has said it is the cavity wall insulation causing the problem has it is saturated. is there a grant she can apply for a grant to have it removed
We have a 1930s house on top of a hill. The brick pattern resembles that of a solid wall house, but it does have cavities. I saw some of the cavities when we had extension work done and they are not fully clear, with rubble / mortar obstructions.
We get driving wind / rain from the south and have had damp problems following bad weather which has prompted us to paint the south side of the property with a water resistant coating.
For all of these reasons, we have not had our cavities filled. However, I was wondering whether to get the more sheltered north and east walls done. Does this sound sensible or if the cavities are old / not fully clear, should I steer clear?
Also some sites suggest that the more expensive foam might be better for tricky properties, but then it doesn’t seem to have the guarantee, so would it be better to get balls?? If balls, I have read that they should be glued, but that seems to make removal much trickier?
Please provide approximate U value achieved with blown mineral or EPS cavity fill.