Heating costs are on the up, and in the UK we have a challenge to keep warm whilst not spending an absolute fortune on our energy bills. In addition to this challenge (now into our 2020’s) as a nation we have stringent carbon targets to meet later on this decade.
With UK properties being one of the leakiest in Europe, external wall solid wall insulation is a fantastic energy efficiency measure to help up not only reduce carbon, but keep heating bill rises in check.
Why choose external solid wall insulation?
Most properties built prior to 1930 were constructed with solid walls, so they don’t have cavities that can be injected with insulation. These solid wall properties can be insulated with external solid wall insulation. The purpose of insulating in this manner is to slow the movement of heat out through the walls, thereby dramatically reducing heating demand.
The embedded video produced by us and one of our partners shows the typical external wall insulation installation process.
In most cases, homeowners get in a professional to install solid wall insulation; it is not normally considered a DIY job. Because the insulating process involves covering the original brickwork, the process can significantly alter the appearance of the property. Since the outside walls are highly visible, it is advisable to get someone who knows what they are doing to install it!
There are many types of insulation products that can be attached to the outside of the home: expanded polystyrene, mineral wool and phenolic resin (K5), woodfibre and even cork! Expanded polystyrene (known as EPS) is certainly the most popular, since it is the most cost effective means of carrying out the works. Phenolic resin (K5 boards) is used when space is a premium, since you can use less of this type of insulation to achieve the required U-value.
Mineral wool can also be used to insulate solid walls and some people choose it because it not only provides an open vapour system, but it is a great acoustic insulator. If it is picked for this reason, it is very important that no acrylic render is used to finish the project, since it is not breathable and therefore defeats the object!
You may choose to use woodfibre if you want the most breathable and natural insulation materials – however the system itself is very expensive compared to the EPS system.
External wall insulation must adhere to building regulations
When solid wall insulation is installed on the external walls of the home, it must adhere to building regulations. In this case it is referring to the thermal performance of the insulation; the solid wall insulation must achieve a U-value of 0.30 watts/m2k. With expanded polystyrene, this means that at least 90mm of insulation needs to be used – but obviously the thicker the material, the better its insulating performance.
For example, according to our competent U-value assessor, James Alcock a typical solid brick wall would require 90mm of the EPS system to achieve the desired retrofit building regulations u-value. Whereas to achieve the same value only 60mm of the K5 insulation board & system would be required.
For mineral wool you need 110mm of insulation to achieve the required U-value and for the the woodfibre insulation you would require 110-120mm of insulation to achieve the same energy efficiency standards.
External wall insulation sometimes needs planning permission
According to the planning portal, planning permission is not normally required for installing solid wall insulation, provided the external appearance of the property doesn’t change. If your property is brick and unpainted, changing its colour with render will require planning permission. Also, if the building is listed or is in a conservation area you should consult your local planning authority.
From our experience of installing solid wall insulation across London, it seems there is no standard approach to how the councils judge what is acceptable and what isn’t, so if in doubt, it is probably worth asking the question!
How is external wall insulation installed?
Firstly, if the property has existing render, a render test must be carried out to see if it is strong enough to hold the insulation. If not, all the existing render will need to be removed prior to attaching the insulation to the brickwork. If the render test shows that the existing render is firmly held in place, the render can simply be smoothed, ready for the insulation to be applied directly on to it.
Another important step prior to installing any external wall insulation is to remove any pipework from the outside of the building. These will be reinstalled at the end of the process (and maybe extended in some instances as necessary); this is one of main reasons that the insulating process is expensive and time-consuming.
Applying the external wall insulation and finishing
The process is relatively complex, but the basic steps are outlined below:
- Insulating panels are fixed to the wall using adhesive mortar.
- Plastic capped fixings are driven through the insulating panels and around their perimeter into the wall to tie the panels securely to the wall.
- Mortar is then applied over the insulating panels and the fixings.
- An insulating mesh is then sunk into the mortar to hold the panels in position.
- The mortar is sanded and painted with primer to prepare it for the render
- The Coloured render finish is applied (available in any colour).
Below you can watch a video where we demonstrate how solid walls are insulated externally:
What external wall insulation and finishes are possible?
As the insulation goes on the outside of your house, it is important that you get the finish that you want.
A house pre and post solid wall insulation
On the whole, the most cost-effective way of insulating your solid walls is to finish it with a simple white render. However there is a huge variety of finishes possible: smooth, textured or painted, tiled, panelled, pebble-dashed or finished with realistic brick slips.
External solid wall insulation and damp
External wall insulation is a great way to protect against penetrating damp, creating a new weatherproof layer on the outside of the building, and slowing the movement of heat through the walls. Another advantage of solid wall insulation is that it will cause the temperature of the walls themselves to rise. This means if there is lots of water vapour in the air (from cooking or washing for example), this will no longer condense on these walls.
While obviously this is a benefit, it is still important to consider ventilation in the home – regardless of whether you insulate or not. This can be done by installing more vents or by making behavioural changes like opening windows and doors while cooking.
Cost and financing external wall insulation
The cost of solid wall insulation is roughly £100/m2, averaging between £6000 – £12,000 for a standard semi detached house, so it is not cheap. However, it can be really worthwhile in the long run. There are occasionally local council grants available for eligible people, and some companies offer finance so it is worth checking.
Currently, the Government Green Homes Grant is available to apply for if you meet the eligibility requirements. For external wall insulation, your property must be solid wall and it must be located in England to be eligible for the Green Homes Grant. The grant offers up to £10,000 off the full cost of the installation which will bring down the cost significantly, and in some cases the grant will cover the entirety of the cost. This scheme is running until March 2022, so there is still plenty of time to get your hands on it!
Advantages of external solid wall insulation
- The insulation will take the U-value of your walls down to just 0.3w/m2k, equivalent to a brand new cavity wall built today – therefore your heating bills will be significantly lower.
- Solid wall insulation stops penetrating damp.
- The insulation can improve the appearance of your home – especially if you are replacing pebbledash.
- It can also really help reduce noise entering the home, so if you live on a busy road it might be just the thing
- Since the walls get warmer, they act as a heat store so rooms will take longer to cool down.
For a more detailed look at the advantages of solid wall insulation please click here.
Installing external solid wall insulation
Interested in getting external wall installation? Lucky for you, we work in partnership with EWI Store who specialise in external wall insulation and render systems! They have a great team who will be happy to advise you on any queries, and can help find local approved installers.
EWI Store are also helping with Green Homes Grant enquiries, and can help you find Trustmark approved installers who are offering the grant.
Has there been any news on the Government grant for solid wall insulation? I just missed out in August, wondering whether you have any news.
Jeremy,
Unfortunately no news as yet. As soon as we hear anything we will be posting an update on the site, so keep your eye out for that.
Hi do you need a damp course for EWI
Hello
Very nice information friend. Actually, I am looking for the insulation of my house in the UK. But I am bit confused in two options now.
The other information I found on the wearezing.com
website.
It will be very nice if you could help me out?
We got our home insulated as part of the home improvement scheme. We got £4k towards it in January and I can honestly say it has made a huge difference to my home. Our house was already rendered, so putting the solid wall insulation didn’t even change the appearance to be honest. I reckon it is just about the best solution for those horrible pebble dashed houses!
Our house has been suffering with condensation and penetrating damp for years. Can you visit our property and see if this is a suitable solution.
Hi Bree can you advise me how you went about applying for this help.
Many Thanks
So we had TheGreenAge / Be Constructive do our install for us last summer. The 12 month figures are in (9 months of which we had the EWI installed) and this was a long cold winter.
Gas usage: £340.03
Electricity usage: £194.85
This is at least a 50% drop in heating costs if not more and much more predicted than the Occupancy Assessment predicted (£180 p.a.).
Yes, we have have an Atag boiler and are 2/3 people but it is four bedrooms (now C rated), We have agreed that if we ever move it would be to a house that has EWI or could have EWI.
Plus we have have had virtually no arguments on keeping the thermostat at 17-18C (the thermostat is in the hall) so the living space is generally 18+C.
Hi Paul,
This is fantastic news – great stuff! It was a pleasure working with you to get the solid wall insulation installed.
We had 150mm of phenolic foam added to our house when we built it on the outside walls, so I think we are near passivhaus now. It is such a good idea, the temperature in the home barely changes throughout the year. The only issue we currently are finding is solar gain on bi-fold doors, but I think we are looking at integrated blinds here to stop this. I can’t believe it has taken so long for interest in solid wall insulation to ramp up.
It seems expensive with limited ROI. I have an old 1895 home and have often considered getting solid wall insulation. My energy bills are approximately £3k per year, I just want to know what the payback would be like before I go and spend money getting the works carried out only to find I need to live till 273 years old to see me get my money back!
Hi Kremp,
By the sounds of it your home is an absolute prime candidate. If your energy bills are that high, a 25% saving on your bills would give you a £750 saving per year. Combine that with a government GDHIF grant of nearly £4,000 and the payback will be swift. Even with a cost of £10,000 you are looking at a payback of 8 years or so. I think a lot of people underestimate the difference it makes – you are taking on of the most inefficient types of wall and bringing it up to the standard of a new build.
I am very interested in getting solid wall insulation on my home. We have an extremely cold flank wall and I think this might be just the ticket. What thickness is best, there are no windows, so I want to balance the best insulation energy savings wise with the cost. I know you suggest 100mm, but would it be better for me to go 150mm instead? What would the cost difference be and what kind of energy savings would I get. The wall is about 7m long by 6m high.
thanks for your help 🙂
Hi Jappie, Like a jumper the thicker you go for the better in terms of energy savings but the material plays a part too! If you go for 150mm insulation then you will definitely see more substantial energy savings and the price difference will be fairly small. If you insulate solid walls using 150mm of insulation then the problem is that it limits the amount of light entering the home. 100mm is about the limit before there is any impact on light – but you have mentioned this is for the flank wall so there is actually no issue here.
I like the look of the solid wall insulation, my property has render already and I guess it makes sense to install the solid wall insulation at the same time. My worry though is how long will the insulation last. On top of this I also need to know if I want to add things later like a satellite dish, is this possible without damaging the insulation system? I guess key to everything is not letting water getting behind the insulation itself, but as soon as you drill a hole in it this makes a gap for the water to get in. Does this then void the warranty?
Hi Ahmad, the insulation should last 25 years plus, but you will need to maintain the walls, i.e. repaint them every 8-10 years to ensure the longevity of the solid wall system.
Try and get solid wall insulation installed under the Green Deal Community Fund. These are funds allocated to local boroughs / councils and the funding tends to be more generous than the GDHIF scheme. We live in Epsom and so fall under the Smart Homes scheme. This is £5k, but there doesn’t need to be any customer contribution; this is substantially higher than the GDHIF scheme so worth taking a look at. There are equivalent schemes running across the UK so do some research! Solid wall insualtion is not cheap, but these schemes make the payback on getting the insulation installed just a couple of years…..
Hi Phil – agreed, it is definitely worth shopping around and trying to secure the biggest grants. The good thing about carrying out the solid wall insulation via these Green Deal community fund is that all the works will be carried out under the PAS2030 framework which will mean you will get a 25 year warranty.
We are really interested in getting solid wall insulation on our semi detached property. I was just wondering which system to use? Are there any we should definitely avoid? Thanks for your help.
Lexie
I live in Chalfont St. Peter, Buckinghamshire in a 1910 detached house. There have been alterations done to it over time (side extension, back diner and conservatory + loft extension), but the majority of walls are still solid 25cm brick and I think we would benefit from wall cladding. Do you know of any show homes near where I live that I can drive and have a look. While I have done a lot of reading about the insulation procedure I would still like to have a look for myself. Thanks for any help.
I am interested in getting solid wall insulation cladding on my home. Is the polystyrene or mineral wool the better product? I really want something that requires mineral upkeep.
Hi Keith, the mineral wool is breathable and fire resistant but is significantly more expensive. The polystyrene (EPS) board has a higher thermal efficiency, so you can achieve the same U-value with less material – it is also far cheaper. 99 times out of 100 we are installing EPS to be honest, but in some cases (normally architects!) mineral wool is specified. The truth is that both products work equally well and therefore the EPS is out preference because the payback is better for the end user, but I am sure others will want to have their say!!
We had solid wall insulation installed on the back of our 1905 mid terrace. They went for 90mm of EPS to take the u-value down to 0.3 which is apparently what is required for building regs.
We got the insulation installed under the first round of GDHIF last summer and so have now had it in place for a year so I thought it would be fair for me to comment on its performance.
Well the first thing to note is that the rooms on the back of the property are far warmer. This was our main objective because that is where the kids rooms are and previously it has been freezing in these rooms. I am not sure on the exact energy savings, but if I were to guess I would say energy usage is about a third down so quite nice. The house is south facing, so one of the benefits we didn’t expect was during the summer, the insulation seems to prevent the home getting too warm, so that was rather an unexpected but pleasant surprise.
In terms of downsides to the solid wall insulation, there really is just one and that is the fact we have lost the brick feel. I know that you can get ‘fake bricks’ to replicate the brick finish, but I am not sure how they would of looked. It is a bit of a shame, but nevertheless really happy we went through with it.
I have seen subsequently that the payments for the home improvement fund have been reducing for solid wall insulation, so I recommend if you are planning on doing it to get in quick.
The other thing worth mentioning and not something that applied to us, but did aplly to friends of ours was that if you need to render the property because the old render looks dated etc, then this is a great time to do it, because the grants more than cover the additional cost of the solid wall insulation.
All in all, I am really glad we went for it and have since recommended it to friends.
Would be possible to give me Contact info for your company Who done your work and I also send me info how th Grant work
I have had this done on my home and it works so well. Energy bills have halved during the winter. I would always suggest solid wall insulation over cavity wall insulation if you can afford it!
We had our external walls insulated by GreenAge / Beconstructive and they were fantastic. Gesek and the other boys on site were polite and worked incredibly hard to get it all done. We had 85m2 insulated with the insulation in under 2 weeks although the weather was great. I look forward to seeing the impact on my heating bills as the weather begins to turn over the coming weeks! On a quick side note though, lots of people in my neighbourhood have gone for cavity wall insulation (with us it wasn’t an option) but surely the old cavities aren’t that thick so you can put an awful lot more insulation on the outside of the wall or the inside (inside the home) compared to insulating a cavity wall? Would be interesting to know the heat loss difference of a cavity wall versus a solid wall both of which have had the retrofit insulation installed on them.
Hi, I am based in Reading and I am looking to get solid wall insulation on my property. The house is already rendered so for me it makes sense to add insulation instead of simply re-rendering the walls. Having said that it does a little bit depend on price, so far I have had quotes ranging from £45 /m2 to 85 /m2 for render. The cheap quote doesn’t include this mesh that people now recommend so probably can discount that one, but wondering how much it would cost me approximately to insulate a 3 bed semi-detached house with solid wall insulation. I want to know whether the incremental costs of insulating and re-rendering are worth it based on the energy savings. Has anyone had it done here who lives in a similiar property? Any thoughts / help would be greatly appreciated, very keen to move ahead before the cold weather sets in!!
Hi Nathan,
As I think you may have suspected, insulating your walls as well as rendering is always going to be worthwhile if you are going to be rendering anyway. There are several good reasons for that:
– The VAT on render is 20% whereas for insulation it is 5%, so you immediately have a 15% saving with insulation works.
– The insulation will create big savings on your bills and help fight damp, whereas render will not really generate any return for you.
– You can’t insulate without rendering, so it is a great time to insulate if you are rendering anyway.
The cost of render vs. insulation taking everything into account isn’t that big. We reckon you are looking at £60/m for render vs. £100/m for insulation. When you factor in VAT and the savings, this difference disappears.
We have been installing solid wall insulation across London under the various government schemes (GDHIF, ECO etc). On the whole the customers who have had the solid wall insulation installed on their properties have been enormously happy with the results. More even temperatures in their home and also not needing to turn the heating on until it gets really cold! The issue the industry now faces is that despite 7 million properties requiring solid wall insulation, the cost of getting it installed is very expensive. So without the subsidies are people actually going to get it in their home? I guess there are two things that will make it more attractive. Firstly energy bills could go up. Especially in the UK where we need to upgrade our energy generating facilities. This will be part subsidised through higher energy bills. Obviously the higher the energy bills the bigger the energy savings resulting from solid wall insulation so this should make it more attractive. Secondly, with VAT where it currently is for solid wall insulation (5% instead of 20% for other works) the cost of getting a house re-rendered or having solid wall insulation installed is actually not that far apart. That means that for homes who are considering re-rendering their properties then it is well worth it, as they will also benefit from the energy savings.
2 pieces of advice for those looking to install solid wall insulation on their home 1. make sure you do some research on the installer. A huge number of installers have popped up over the last 18 months. Make sure you can check their previous work and ideally speak to a customer of theirs. 2. Make sure they are using a BBA product. There are about 40 systems available in the UK, but some of these haven’t been through the process and as such I would be very wary. The BBA shows the quality of the systems being installed.
As a final point if you are having solid wall insulation installed check the installers maintenance recommendations. Many installers hide the fact the walls will need re-painting in 10 or so years. If you have a 4 story house the cost of the scaffolding to get this done can be expensive!
Thanks for your comments Dan, agree with everything you say. The Government really is making the energy saving sector a challenge at the moment, but I think long term, solid wall insulation could be a winner. I think one thing you have missed is that old cavity walls are limited by the width of the cavity in terms of the thermal performance upgrade they can receive. Older cavity walled properties could have a cavity just 40mm thick. This means that even if you were to go with cavity wall insulation, you would only be 0.65w/m2k. If you install 100mm of EPS solid wall insulation, you can acheive a u-value of 0.28w/m2k. This is a substantial improvement, so it may be worth considering solid wall insulation even if you have cavity walls! Completely agree though it makes sense for people have previously rendered properties because of the VAT issue. It looks though as if the Government are even looking to change that, so take the VAT up to 20% which isn’t going to help the industry establish itself. Not sure what is going on a DECC, but it seems that energy efficiency is taking a serious back seat!
A question…. how does single wall insulation work around the windows? Does it change the look very much?
Hi Janeking, yes it does – the window will be recessed after the insulation is added. How much is dependant on how much solid wall insulation is added. When we install solid wall insulation on properties, we do normally suggest windows are done at the same time for two reasons. Firstly the windows can be pulled out a little so they don’t look so recessed within the wall. Also, replacing windows once solid wall insulation is installed is a bit of a pain – because it will damage the insulation meaning you will need to pay the solid wall installer to carry out repair works.
Hi I’m enquring about the rendering grant, is this a full grant? I own a 2 bed mid terrace and I am looking to get it re rendered as the rendering that is on now isn’t very good and looks messy, is there anything you can do?
Some interesting comments. We got solid wall insulation installed under the HIF scheme and some guys who couldn’t speak a word of English did a really shoody job. We then found another installer to come and rectify the works, but it came at great expense. I am surprised that the first group of installers were on the Government recommended installer list. How on earth did they get through the quality checks. Anyway now works are done and we are happy. It looks good and over these winter months it has made a considerable difference. It is amazing though how much the quality of the installers varied. ADVICE IS ALWAYS TO CHECK SOME WORKS THEY HAVE PREVIOUSLY CARRIED OUT AND GET A CHARACTER REFERENCE FROM A PREVIOUS CUSTOMER OF THEIRS!
Hi James, I live in Perivale, north-west London and my mum is on the state pension. I heard from one of the neighbours that there is Government funded scheme to help with the wall insulation. Do you have any more information on this? My mum is elderly and frail and her current heating just cannot warm the front room enough for her to sit during the cold.
Hi Jane, their are two streams of grant funding kicking about at the moment. The first is the ECO funding – this is not a set amount, it is calculated based on the theoretical carbon savings resulting from the improvement in energy efficiency from the house’s current state to the new more energy efficiency state. Not all companies offer this so you will need to find a local company that does and also it is difficult to give you the exact amount of the grant becuase it depends on the size of the property, what type of property it is and also the existing efficiency.
The other type of funding is known as the Green Deal community funding – this is a lot simpler and tends to be a set value however not many councils have access to this so you will need to check – I actually think off the top of my head their is funding in North London
we looked at getting solid wall insulation on the flank wall of our house but unfortunately the pathway between our property and the neighbours was too narrow for conventional scaffolding. It is very very cold in december till March and I was wondering if a) there are companies who can insulate not off conventional scaffolding? Ladders maybe? and b) if we can’t get solid wall insulation on our home what other options do we have aside from internal insulation. We definitely can’t afford to lose the space off that wall and I think the upheaval would give the missus a breakdown. Is there a thinner product that can go on externally that really helps prevent heat loss? I did read about an insulating paint but not sure if that would provide any real heat savings?
We are considering external insulation but I wondered if the roof needed any altering given that the external walls will be thicker?
You can extend the roof line or cap the top of the external wall insulation (the capping is far cheaper). In many cases however the existing soffit extends well over the wall and therefore can house the thicker external walls.
External wall insulation my daughtermoved into a property with insalation on her property i notice they have not put any pattreses on the outside fittings aerials.lights rain water down pipes can these pattresses be put in know or would it cause a problem.Graham
We had this done after getting our holiday home done out in Geneva where the temperatures get much lower. The solid wall insulation makes a massive massive difference. House is always nice and warm. Put heating on it stays hot forever. In uk temps are warmer so obviously less of an impact but still definitely worth doing.
Hi Xander, thanks for your comment – I think the solid wall insulation industry is far better established in continental Europe, however I think the UK is catching up basically because there has been a shift in the Governments view on this. The reason for this is that there are very few cavity wall properties that are still to be insulated, so they have had little choice but to start targeting the older solid wall properties.
I’ve noticed the dry fixed systems are cheaper than ones that require adhesives. But adhesive solid wall insulation systems like Jub, Alumasc and EWI Pro require less fixings than a dry Weatherby one – surely there is then no difference on performance?
Hi I have just sent a request through for a quote for external solid wall insulation. The bungalow at 38a Rustat Rd is 13.6m x 11.4m, and the external walls will be at 2.4m. The property is undergoing renovation at the moment, and there will be 3 sets of 3m bi-fold doors on the back elevation. Please mail me if you need any other info
What is thinnest material you can use for solid wall insulation? I have a very narrow walkway.
Hi Seb, some companies do use PIR board (like celotex / kingspan). The danger is though that this can sometimes shrink over time, so cracks appear in the render which can then lead to water ingress and all sorts. To be honest, you are better off using EPS or mineral wool (or even something like cork). Just use a slightly thinner amount – obviously you won’t achieve the same thermal performance, but you will get the benefits of the trade off between space taken up and improved thermal performance of the wall.
Having tried to get cavity wall insulation installed, we ended up getting solid wall insulation installed on our house after we learnt we didn’t have cavity walls! They used the wetherby system with 90mm of foam insulation. It has made a tremendous difference to both the appearance of our home and also the energy bills. I reckon the are less than half what they were last year. The insulation means the house warms up in about an hour and stays warm. It used to be on a programmer to come on at 5am and I don’t think the house ever hit the 20 degrees thermostat setting so the heating was on all day! Really happy with the result.
we got external wall insulation under the GDHIF scheme. Total job was 9850 and we got £6k off the cost of the works. We save approximately 600 a year on our energy bills now due to the increased energy efficiency so payback should be 7 years. The render finish has also really improved the look of our home (used to be pebble dash). I know it is expensive (unless you can get your hands on a grant!) but it really is worth it.
Hi Ben, thanks for your comment. You were lucky to have got on that GDHIF scheme – it went extremely quickly! In our opinion solid wall insulation is one of the best energy saving measures out there. The reason being is that you really do produce substantial energy savings. Take cavity wall insulation for example – older uninsulated cavity walls tend to only be 50mm thick at the most, so you are therefore limited to 50mm of insulation. With external wall insulation, in theory there is no limit to the thickness of the insulation you use therefore you can use a lot and get huge energy savings!
Hi there, I am looking for an installer in the Essex, Suffolk area. We have a typical 4 bedroom semi-detached house in Braintree. Been struggling to find a good ewi or rendering company as most of the ones that I call off this Government list will only do work for people with benefits. Also since we are going to live in this house (touch wood) for at least the next 15yrs or so, I don’t want any expenses spared and want the best system. I have heard Sto, Baumit, EWI Pro Insulation and Weber sell quality products. Please don’t offer me installers that offer acrylic render finishes, I expect my house to breathe once the insulation is applied.
Thank you for all your help! We have just had the insulation installed by an installer you recommended over in Essex and the house looks all the better for it. Obviously can’t really feel any benefits yet in terms of energy savings as heating has been off but hopefully next year we will really benefit. Anyway just a quick note to thank Alan, really helpful through from my intial enquiry and following up to see we were happy, a thoroughly proffesional service!
Hi Adam, we are really glad we could help you with your project! Hopefully it will keep that flank wall a bit warmer next winter!!
Hi
we are considering external wall insulation and wondered if there are any grants around at the moment
regards
R Webster
We got external wall insulation about a year ago. During a recent session of heavy rain, water started getting in around one of the windows frames.
The only way I can think this could be happening is if water is running between the external wall and the external insulation but your video suggests that that should not happen due to the panel being firmly fixed to the wall.
Does this mean that there is a problem with my external insulation?
Thanks,
Hi John, this may be the case. With wet fix solid wall insulation systems (when the boards are attached to the walls with adhesive as well as mechanical fixings) this normally can’t arise as adhesive is applied to the perimeter of each board as a minimum before it is fixed to the wall. There are companies out there who install dry solid wall insulation systems (just use the mechanical fixings to tie the boards to the wall). In this case, water could travel down the back of the boards, so they need to be very carefully sealed at the edges of the walls (by the soffit, DPC etc).
The problem with water getting behind solid wall insulation is that during colder weather, the water could freeze and expand pinging the boards off the wall. We would always recommend going with a wet solid wall insulation system.
What if I can’t meet building regs? There isn’t enough space for 10cm of insulation?
Hi Xav, we will come back to you on this! We are waiting on a formal response from building control. This does occur quite a lot with solid wall insulation espically when you have semi detached properties with thin alley ways between them.
Is there a company you can recommend in Bristol for external wall insulation. My house is in the conservation area and I will need planning from the local council. The building is divided into two flats and I like to know is there any grant available for wall insulation in our area and the cost of insulate my house which is four floors and just insulate the back wall and side.
Thank you.
Hi Mr Wong – try Elite render – they do EWI in your neck of the woods!
Can you attach things like hanging baskets and fence posts to the eps and if so with what and how
Hi Ian,
You can indeed – there are two ways – the first is fixings that are anchored into wall itself (the brick part). There are also spiral fixings which can be used – these basically have a very wide thread to spread the load through more area of the insulation.
I had external wall insulation installed over 2 years ago using the EWI Pro Insulation system. In the end I had a choice of using a company called Pro EWIs to install it or mmy local builder. In the end I chose my builder instead of the contractor to my detriment but anyhow we got there in the end. I am planning on adding a side return which will go into the system and potentially damage it. Do you know what am I best options to obviously preserve the integrity of the EWI system as well as continuing the works? Also what do I do about colour matching of render, so I get exact texture. Should I speak to EWI Pro Insulation Systems direct? Also do you know if Pro EWIs are one of your approved installers?
I have a rendered wall with pebble dash, can I apply the insulation on top or do I have to take it all off first?
Hi Gary, this depends on the strength of the existing render – we would recommend doing pull test on the underlying render to see that it will support the new layer of render on top. If the existing pebbledash is flaking off or coming off in parts, we would definitely recommend stripping the whole thing prior to applying the new render layer. Adding an insulation layer under the render helps (as in solid wall insulation) because these are attached with mechanical fixings – so that helps tie the system to the wall.
We are very interested in getting solid wall insulation installed and we are based near swansea in south wales. Can you recommend an installer for us in the area. Are there accreditations that installers need to have? Thanks for your help!
i am interested in getting solid wall insulation installed and wondered if you know of any companies that install it and what grants are available. i am based on the isle of wight.
Hi Jan, there are a few schemes running with small grant pots available, but they tend to be very localised to specific locations around the country (for example there is a scheme in Enfield at the moment). Unfortunately I have not heard of any being available of the Isle of Wight at the minute.
Interested in getting Whole house solid wall insulation
Hi Sam,
Where abouts in the country are you based?
Hi. We are deciding whether to install external wall insulation in our 1900-built terraced house. Would it be possible to carry out the installation during winter? or is that not recommended?
I have a 1975 bungalow. It is timber frame with block work covered with harling. There is a small amount of cavity wall insulation but not enough and there appear to be gaps. Is it possible to put insulation on the outside of walls like this. If yes, are there any firms carrying out this work. I live in Midlothian, Scotland.
Hi, Do you know of any schemes running in Watford for the solid wall insulation
Hi Martin, unfortunately not at the moment. Not sure whether grant based schemes will make a return as they were in the previous iterations of Government energy saving policy. The latest Government review into energy saving only mentions finance based mechanisms, and there is little on “grants”, only glancing ECO, which can vary depending on the funding levels from the energy companies.
I recently had this done in crewe Cheshire cw13eb by abr energy I now av damp inside the bathroom wall who do I contact can’t get hold of abr energy
Hi Marion,
Was the company PAS 2030 certified? If so, any remedial work needed because of a fault by the installer should be covered by insurance. Dig out your paperwork! Bear in mind thought that the wall may be damp due to a lack of ventilation in your bathroom – it is very unlikely to have been directly caused by the external wall insulation.
Always take your time and decide about the right type of glazing consider life span, right appearance and usefulness. Window glazing is typically a lifetime decision
If Secotherm from the company Energysave is applied to the outside of my property, what benefit will there be to the heat of the inside of the house?
Hi John, As far as I can see, Secotherm is just a type of waterproof (clear) paint. Basically the paint is painted on the exterior of the property and since it is waterproof it stops penetrating damp. The reason this company reference energy savings is that dry walls are better insulators than wet walls. Test data has demonstrated that dry bricks have approximately twice the thermal efficiency of saturated bricks. It is a sound theory however I would not like to put a value on the kinds of savings that Secotherm would produce, because it depends on how damp your home is at present! You would be better off adding insulation externally or internally to the walls exposed to the outside. With this, provided you add sufficient insulation then you will definitely see decent savings.
To be honest, it is the same kind of reasoning that DPC injection cream manufacturers use. The DPC is installed when properties are built to help prevent water from being pulled up the wall by capillary action. The DPC acts as a barrier to the passage of water. In older properties, the DPC can sometimes disintegrate, meaning water can travel up the wall. The DPC injection cream is injected into the wall to try to re-create a new DPC to help stop damp travel upwards. So the theory is, that this cream will help stop water being pulled up the walls (rising damp) which will help keep the walls dry, which should therefore help the performance of the brick in terms of heatloss.
As I said, I think the real energy savings will come from the external wall insulation basically because the render will also provide this water proof coating but you will also benefit from far slower heat loss (in the winter) and heat gain during the summer.
We,ve just moved into a retirement village, which has been thermally insulated and rendered . As it has a thin shell of rendering , is it possible to fit a thin lightweight aluminium no parking sign up on the wall without causing any damage, could plastic rawplugs be used with a sealsnt on the rear of the screw to secure it
Hi Gregory
It should be possible in theory, but it could affect your installer-backed warranty. The best idea is to contact the installer, or if that’s not possible, get in touch with the system manufacturer.
Do you know of any schemes running in Leicester for solid wall insulation
Thanks
Hi Jayne.
Not at the moment I’m afraid. But if you’d still like to look into the measure and need any further information, feel free to get in touch!
Very useful video to show what solid wall insulation is.
We live in the Carmarthen area of Wales, are there any approved installers of external insulation for solid walls in our area?
This is all very sustainable and efficient but how does the tenant construct an extension fixing into sheets of insulation.
Hi Mr Fisher, thanks for getting in touch. Basically, the insulation would have to be cut into (using an angle grinder normally) and then made good once the new extension has been built. Normally much of the damage of cutting into the insulation can be hidden using lead flashing provided you know exactly where the extension will be coming up to on the insulation.
It it 100% fireproof?
Depends which products…. Mineral wool (e.g. Rockwool) is 100% non combustable – it is made of stone. In external wall insulation systems though the insulation is enclosed within a concrete based mortar which helps.
The rainscreen cladding system used on the Grenfell tower was as far as we understand made of uncovered insulation (i.e.the fire could touch the insulation material itself). A cavity which acted as a chimney drawing the fire up the property and a potentially flammable outer cover (which again we understand is banned in America).
Rainscreen cladding is not the same as external wall insulation – they are two very different systems.
Re question below:- “is it 100% fireproof?” and partial answer by James Alcock.
Specifically, is EWI – 110 Thickgrey EPS fireproof? If not, 1) does it not pose a FIRE risk(*) for close neighbours? 2) does it comply with building regulations in UK
(*) as EPS is lightweight and could detach / fly away in case of fire…. Possibly landing on neighbour property
This is to the ‘worried comment’. What about wooden frame windows, thatched roofs, timber frame properties, wooden front doors, roof timber and a list of other building materials that could be flammable. In the Greenfell witness accounts, I heard one of the victims shout out how their window was on fire. Presume the windows in the flats were uPVC?!
Hi, Grey EPS is not fireproof. It would melt and eventually burn if you put a flame to it (like many building materials). The key is how it is installed. the EPS is attached to the wall via a cement based adhesive and then there is another layer of adhesive added to the outside of the insulation. Therefore the insulation material is cocooned within non combustible adhesive – it is therefore safe! To be sure, always look for a BBA approved EWI Product, Sto, EWI Pro, Weber etc. All have been tested rigorously and do comply with building regs.
In response to the other question is hugely unlikely the boards could detach and fly away. They are held to the wall with cement based adhesive. They are then held in place mechanically with mechanical fixings then finally they are further reinforced to the wall by a fibreglass mesh / cement layer.
Do we have to advise our insurance company if we have had external wall insulation fitted?
Just been reading these comments. You don’t have to advise the insurance company that the measure has been fitted. You wouldn’t do so if you installed new windows or had a loft extension built. We are an external wall contractor in Middlesbrough and we always self certify the jobs, which means the customer would receive a building control compliance certificate a few days later.
I am very interested in getting solid wall insulation installed on my property. I am wondering which products to use though as `I have been doing some research on the internet and some people suggest Kingspan external wall insulation board. but others say this is unsuitable? It is thinner therefore I think would suit my property better as I have quite a narrow walkway on one side of my property.
I have been offered a significant grant for external wall insulation on my Swedish Timber semi-detached house in the Highlands. would you recommend this? I am concerned about the timber underneath being/getting damp. Also that my house is very exposed and ‘shakes’ in strong winds… There are some cracks on internal plasterwork due to this. Will the external render crack? And can the exterior be damaged by say – my son regularly kicking a football at the wall? Lastly, will it affect my home-insurance (perhaps become non-standard building type?) Many thanks for this helpful website forum. Lauren
We probably wouldn’t recommend it I’m afraid – it would have to be a very flexible system indeed!
We had solid wall insulation installed under the green deal voucher scheme six years ago. The cost of the works was £8,700 but we had a voucher for £6,000.
I would say our gas bill is now less than half what it was back then so it seems the solid wall insulation really is a great way to help keep your home warmer.
Hi my house was built in 1895 and has a cavity. At some time in the past it was rendered which now needs replacing and I think putting cladding on then render is best option van this be done even with a cavity ? Advise appreciated. Regards Mal thomas
Hi Mal. Yes, it can!
We have an old brick coal shed at the back of our house which is single skin. We are currently using it for a utility area but we are suffering with bad damp. Would this system benefit us and help to reduce the amount of moisture that builds up!! Many thanks in advance
Hi,I have had cladding insulation done on my wall all is good and effective,but moss has slowly started to form on front of the house..can this be treateda and what would it cost on average
Hi Raghbir, depending on the type of render, it can normally be removed mechanically with a brush and water. I know some renders can also be power sprayed clean – I would check with the manufacturer.
Does this product need to be installed above ground level/dpc, with say a starter track, so as not to bridge the damp proof course?
Are grants still available for external wall insulation
Hi John,
It depends where you are. You may be able to get partial funding under the Energy Company Obligation (ECO) or, if you’re in Scotland, the Home Energy Efficiency Programmes for Scotland (HEEPS). There may also be local funding schemes in your area.
Your best place to start would be to call your energy supplier regarding ECO funding, and your local council to find out if there’s anything local available to you.
Many thanks,
Harriet
Can you fix lights/hanging baskets once the cladding is installed. If so what sort of fixings would be required?
I’ve had Sto render installed in 2007 to our office building. I am not sure whether it was the regular acrylic render or the insulated render that you talk about in your blog. Over the years we noticed discolouration and staining towards the bottom and some more exposed sections of the walls. Last year we had mechanical damage to the system and we were on the lookout for full refurbishment of this render system. However, due to budgets we pushed the project back a year. Now we are ready for full refurbishment again. What is the best way to proceed. Can another EWI and render system go over the top?
Hi Oliver,
In my experience we would never simply go over the top of an existing thin coat render with another coat of render – you would need to rebasecoat the system first (which is the thing that provides the strength and flexibility to the render system). The base coat is made up of a cement based adhesive with an embedded fibreglass mesh. Once this has been applied you can then reapply the render layer.
The fact the render stained suggests it was an acrylic render, but the newer Silicone renders are hydrophobic so help repel water keeping them stain free.
In order to refurbish the system you therefore have a couple of choices, you can just apply a new layer of base coat + mesh and then a Silicone render topcoat, however you may wish to go down the insulation route which will help improve the thermal efficiency of the system too. It is now recommended 90mm of EPS is used, but if thickness is a problem you can use Kingspan k5 insulation board which saves you a bit of space.
If you have any specific queries let me know.
great information but I am looking to insulate on the outside but then timber clad for the finish is this possible with this system
are there any companies that are taking part in the green home grant scheme and cover the NW4 area of london and prepared to quote for the work.
I live in an end of terrace house, would it be worth getting just the end wall clad with EWI?
Hi, We have solid walls and I have had problems with condensation and black mould especially during the cold winter months (despite using a dehumidifier in my kitchen which seems to create most of the condensation / moisture). Would installing external wall insulation help resolve this ?
Hi
I would like to get external insulation for my bungalow but the issue I have is the wall where the drive to the garage is. It’s already only just wide enough to get a small car down which would then be impossible if narrower. Any advice would be appreciated.
My house was built in 1926 with single wall construction. I want to improve insulation at the front. It is about 5 meters high and 9 meters wide. But there are a lot of windows. so the area to cover is a lot less than 45 square meters.
At present, it is covered in pebble-dash which, despite its age, is very sound. Because of the windowsills et al, I only want the coverage to extend for about 2.3 cm from the present surface. When the insulation is in place, I want the outer appearance to be a plain, flat wall.
I have a contractor lined up to do the job who is very good indeed. Being Polish, he has experience of this sort of insulation job as many houses in Poland use this method to keep out their very cold winters. But he doesn’t know English suppliers.
Can you supply a ‘kit’ of all the materials needed? It has to be quite soon as the job will be done next month. I will also need to time the job at the time I can hire a scaffold tower.
All advice and comments will be very welcome as I have no experience of this type of job.
Thanks
We are looking to insulate the outside of a semi-detached older house built in 1923. Need advice, please.
Don’t like being locked into your commercial promotion with no back button – of veryuser friendly
Hi All, just a note on this page (May 2024) – there is currently a decent amount of funding available for external wall insulation when you have it installed on your home. This includes ECO (although you will need to be on some sort of government entitlements to benefit from this). There is also a scheme called GBIS that is pretty much a grant and typically covers the cost of the materials when installed by an approved installer. For more information on this – please go to http://www.EWIPro.com. Remember too that VAT on EWI is zero percent – so when comparing the final price to render (which has 20% VAT) there is not really a lot in it.