Retro-fit cavity wall insulation.

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Doubt anyone gonna get done for it, would be surprised

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zolco said:
Doubt anyone gonna get done for it, would be surprised

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I bet the banks said the same when people started looking into PPI. The construction industry is getting more focus on it for a variety of reasons. Once a government working party gets involved someone is going to get reamed, and as that won't be the government department behind it that only leaves the businesses that saw a quick buck opportunity.
 
imago said:
I bet the banks said the same when people started looking into PPI. The construction industry is getting more focus on it for a variety of reasons. Once a government working party gets involved someone is going to get reamed, and as that won't be the government department behind it that only leaves the businesses that saw a quick buck opportunity.
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You might be right but it will be a lengthy process, as it's backed by energy suppliers to counterbalance their emissions and taxes and whatnot and endorsed by UK government from UK taxpayers money and fitted by a third party. Doubt British gas will take responsibility for any insulation fitted by Joe blogs company. Joe blog will fold the company so he won't pay, then bs might setup a compensation fund, and solicitors will be all over it like flies on a dead horse

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zolco said:
You might be right but it will be a lengthy process, as it's backed by energy suppliers to counterbalance their emissions and taxes and whatnot and endorsed by UK government from UK taxpayers money and fitted by a third party. Doubt British gas will take responsibility for any insulation fitted by Joe blogs company. Joe blog will fold the company so he won't pay, then bs might setup a compensation fund, and solicitors will be all over it like flies on a dead horse

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Oh it'll take years all right, but it will be the energy companies that get slapped first as it's too time consuming and expensive to go after the installers.

The annoying part about it is that everyone knew in the beginning that it was a bad idea. Basic physics and common sense really.
"These houses were built with cavity walls to stop moisture transfer."
"Yeah."
"Well now we're going to fill the cavity up to stop heat transfer."
"But if you fill the cavity won't the moisture just ....."
 
imago said:
Oh it'll take years all right, but it will be the energy companies that get slapped first as it's too time consuming and expensive to go after the installers.

The annoying part about it is that everyone knew in the beginning that it was a bad idea. Basic physics and common sense really.
"These houses were built with cavity walls to stop moisture transfer."
"Yeah."
"Well now we're going to fill the cavity up to stop heat transfer."
"But if you fill the cavity won't the moisture just ....."
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I hate cavity walls with a passion, whoever had the bright idea to be a standard should be...

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zolco said:
I hate cavity walls with a passion, whoever had the bright idea to be a standard should be...

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It was simply the cheapest construction method, nothing more to it than that sadly.
 
imago said:
It was simply the cheapest construction method, nothing more to it than that sadly.
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How come? You almost pay double for labour and it's difficult to keep it dry during the build. Big clay blocks are the future, shame there isn't a factory for them in this country, as the prices are just bonkers getting it in from a merchant here.

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zolco said:
How come? You almost pay double for labour and it's difficult to keep it dry during the build. Big clay blocks are the future, shame there isn't a factory for them in this country, as the prices are just bonkers getting it in from a merchant here.

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Because they were coming from solid 9" brickwork, and going over to a 3" skin of brick with a cavity and a 3" skin of the cheapest shitty blocks, or timber stud and plaster.

Even if you stuck with two brick skins you'd save 33% on brick and mortar, but using an inner skin of the old cheap thermalites the saving was up to 40-45% and the saving with a timber inner stud was up towards 60%.

Spread that sort of saving over estates with hundreds of houses and you're making a metric s**t-tonne of extra profit.
 
I, and a couple of the other lads on here (I passed their numbers on) have worked for one of the biggest loft/wall insulation companies in the country. Foot thru ceiling and drilling too far thru cavity walls being the source of the work. I used to do surveys and price and carry out work for them before the government, yes, government withdrew funding. (Via the energy companies to comply with eu laws to reduce carbon)

Having done 100's of jobs afor them the very, very few of them that had dampness problems fell into 2 categories. No air vents/plastered over vents or tenanted properties where they wouldn't open the windows, causing mould aka rising damp.

The tenanted properties had mould BEFORE the cavity insulation but the thicko reps misdiagnosed it as cold walls. Joe Daki regularly puts in compo claims for this and when my decorator used to go I and re decorate while warning that the mould will come back if they don't open windows Joe would later try and claim cash compensation again.
 
Interesting read
I got 1950s house with cavity insulation done 10 years ago,no problem's.
What else would people of recommended they do instead of cavity wall insulation if it was that bad of an idea?
Iwi or ewi ?
Nothing is guaranteed.
Where there's a blame,there's a claim
Good old british way.
 
Has any one heard of cavity clearance? That pretty much proves that the insulation In the cavities is pretty much f**k*d in certain geographical areas and when certain insulation is used


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themucky1 said:
Has any one heard of cavity clearance? That pretty much proves that the insulation In the cavities is pretty much f**k*d in certain geographical areas and when certain insulation is used


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The insulation in our place was sopping when I looked last and it was patchy...

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Surely companies like Stormdry will clean up now with these problems. It's the only way to stop further water getting through.
 
It was/is a bad idea because it's a half 4rsed approach. You can't change one aspect of a building's construction without affecting others.

Cavity insulation can and does work perfectly well if the right material is used in the right way. All it needs to do is stop heat transfer from the inside to the outside without causing moisture to travel in the opposite direction. So if celotex foil faced slabs are used, they are kept tight to the inner leaf. The air gap that's left for ventilation prevents moisture build up and transfer.

Sealing the outer leaf is possible, but it's very expensive as it's not just the face that needs doing but all the reveals, door and window edges, top of the wall at roof and base of the wall at DPC level. A cheaper alternative is forced or mechanical ventilation. None of these are practical to do remedially.

EWI is probably the least efficient insulation method. All the figures for EWI are based on readings taken from outside the property with a big hoo ha "look how much heat loss it's stopped!". The heat travels out to the EWI, but the outer leaf acts as a heat sink and stores most of the heat energy there which is of no benefit to the interior. All the moisture travels in the same direction and stops at the same point.

The best and most effective method of retro fitting insulation to a building is on the inside using a stud to hold the insulation away from the wall. Obviously it's expensive to do, very disruptive to the occupants, and they loose room volume so it's not very popular.

Whichever method of insulation is used the key thing is to make sure that the right ventilation method is used with it to control air flow and moisture levels/humidity.
 
imago said:
It was/is a bad idea because it's a half 4rsed approach. You can't change one aspect of a building's construction without affecting others.

Cavity insulation can and does work perfectly well if the right material is used in the right way. All it needs to do is stop heat transfer from the inside to the outside without causing moisture to travel in the opposite direction. So if celotex foil faced slabs are used, they are kept tight to the inner leaf. The air gap that's left for ventilation prevents moisture build up and transfer.

Sealing the outer leaf is possible, but it's very expensive as it's not just the face that needs doing but all the reveals, door and window edges, top of the wall at roof and base of the wall at DPC level. A cheaper alternative is forced or mechanical ventilation. None of these are practical to do remedially.

EWI is probably the least efficient insulation method. All the figures for EWI are based on readings taken from outside the property with a big hoo ha "look how much heat loss it's stopped!". The heat travels out to the EWI, but the outer leaf acts as a heat sink and stores most of the heat energy there which is of no benefit to the interior. All the moisture travels in the same direction and stops at the same point.

The best and most effective method of retro fitting insulation to a building is on the inside using a stud to hold the insulation away from the wall. Obviously it's expensive to do, very disruptive to the occupants, and they loose room volume so it's not very popular.

Whichever method of insulation is used the key thing is to make sure that the right ventilation method is used with it to control air flow and moisture levels/humidity.
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I semi agree with your points however ewi is much better especially on a solid construction without any cavity, yes the heat have to travel through the wall and all but in this country where temperature not that harsh during the winter and summer is hard to compare. On the continent where temps can plummet into the heavy minuses that's where you got the real benefit. On a 300mm wall if you install a 50mm ewi you cut your heating bills in half as soon as the boards are on the wall. An engineering architect can give you calcs for different scenarios regarding insulation on different construction methods and what and how they effect temperatures and ventilation.
If you want a space saver internal insulation try aerotherm. Anyone done any yet?

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zolco said:
I semi agree with your points however ewi is much better especially on a solid construction without any cavity, yes the heat have to travel through the wall and all but in this country where temperature not that harsh during the winter and summer is hard to compare. On the continent where temps can plummet into the heavy minuses that's where you got the real benefit. On a 300mm wall if you install a 50mm ewi you cut your heating bills in half as soon as the boards are on the wall. An engineering architect can give you calcs for different scenarios regarding insulation on different construction methods and what and how they effect temperatures and ventilation.
If you want a space saver internal insulation try aerotherm. Anyone done any yet?

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I'm not saying it doesn't work, just that it's the least efficient.

Compare the figures for internal and external insulation and you'll see there's a massive difference. The often quoted 50% reduction in energy bills for EWI under the best circumstances goes up against an 85-90% reduction for internal insulation.

EWI vs nothing and EWI will be a huge improvement no question.
 
imago said:
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EWI is probably the least efficient insulation method. All the figures for EWI are based on readings taken from outside the property with a big hoo ha "look how much heat loss it's stopped!". The heat travels out to the EWI, but the outer leaf acts as a heat sink and stores most of the heat energy there which is of no benefit to the interior. All the moisture travels in the same direction and stops at the same point.

The best and most effective method of retro fitting insulation to a building is on the inside using a stud to hold the insulation away from the wall. Obviously it's expensive to do, very disruptive to the occupants, and they loose room volume so it's not very popular.

.
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Are you sure about the ewi being the least efficient. I was made to believe that with the internal walls absorbing some of the heat, once the heat is turned off it radiates back into the house which seems a good thing to me, esp in winter when one is going to bed and waking up. As for the internal slabs, yes they are great for quickly keeping heat in but once heat is turned off, the house losses it quicker!

I'm going to be upgrading my insulation this summer and have been leaning more towards the EWI. I've a few boards already in of xtratgerm for the voids in my roof and will be buying more to fill them all. But you've just thrown a spanner in the works now with me thinking of getting the EWI on my own house :( The internal insulation doesn't sound to bad but it's Alot of fcuking about to say the least. It's OK when it's a new build or an extension but a house that's getting lived in, it's a nightmare situation. Wouldn't be to bad in a small terraced house but mines is a 2500sq ft 6 bed and 4 bathrooms are all tiled. Alot of messing to get this internally boarded out!
 
hail hail said:
Are you sure about the ewi being the least efficient. I was made to believe that with the internal walls absorbing some of the heat, once the heat is turned off it radiates back into the house which seems a good thing to me, esp in winter when one is going to bed and waking up. As for the internal slabs, yes they are great for quickly keeping heat in but once heat is turned off, the house losses it quicker!

I'm going to be upgrading my insulation this summer and have been leaning more towards the EWI. I've a few boards already in of xtratgerm for the voids in my roof and will be buying more to fill them all. But you've just thrown a spanner in the works now with me thinking of getting the EWI on my own house :( The internal insulation doesn't sound to bad but it's Alot of fcuking about to say the least. It's OK when it's a new build or an extension but a house that's getting lived in, it's a nightmare situation. Wouldn't be to bad in a small terraced house but mines is a 2500sq ft 6 bed and 4 bathrooms are all tiled. Alot of messing to get this internally boarded out!
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That's the problem with it, as I said it's a nightmare to do internal insulation in an occupied house.

The heat doesn't dissapate faster from an internally insulated house, it's slower as it has nowhere to dissipate to. If you think about it you're basically building an insulation box with the heat source inside it.

The amount of heat available to radiate back into the house is tiny because the mass of the walls is relatively small. It would work better in the solid stone walls, or the turf filled stone walls. The problem is though, just imagine how much energy is absorbed into the walls without doing anything to the house until the wall temperature reaches 12 - 15 degrees and the absorption slows.

The ideal is to have all the heat you produce in the house contained within the room areas that you use. That way your energy bills are tiny as getting the air up to 20 degrees can be done quite quickly. Due to minimal heat loss keeping it there requires very little energy.

Given what you're place sounds like I'd be going for EWI too unless I could afford to move out and gut the place. Make sure you've got at least two feet of loose, or 8 inches of slab insulation in the loft space as that'll make a much bigger impact than insulating the walls.
 
Really do find the ewi,iwi,cavity debate interesting..
I'm not as intelligent as alot of you on here especially when it comes to the cavity side of things..
Can anyone tell me why not all three ?
My thick mind tells me that with outside inside and middle done then not alot is going in or out?
 
theplasterman said:
Really do find the ewi,iwi,cavity debate interesting..
I'm not as intelligent as alot of you on here especially when it comes to the cavity side of things..
Can anyone tell me why not all three ?
My thick mind tells me that with outside inside and middle done then not alot is going in or out?
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Cost basically, with a secondary issue about space taken up.

The building we were in at the base in Antarctica obviously had insulated walls. It was the latest spec available at the time (1990) and had to withstand static temperatures down to -60 celsius, and wind speeds up to 100 mph. The walls were eight inches thick and made of two coated plywood panels with insulation in between.

The base was 10 metres wide, and fifty long. The whole thing was heated by the heat reclaimed from the exhaust gasses of a single cummins six cylinder diesel engine running the generator. The size of a small truck engine. At full chat the kwH output was about 60% of that used to heat a three bedroom house with a combi boiler in the UK.

It's all about the efficiency, but it costs a fair bit to set up in the first place.
 
Don't know which post to quote tbh, because they are all connected in some way and even if you switch them , they still make sense. Anyway, my 2 p
Cavity insulation never made sense to me and never will, whether is tide , impossible to do, to the external and internal wall do to so many factors. All celotex board do is to sent the moisture down with the speed of Olympic skier champion thanks to the foil.You still have the external exposed to the weather conditions and internal wall to heat loss. Total waste of money and time IMHO . Internal insulation have great benefits, but also negatives . That's bigger pita than EWI . The biggest challenge is to explain customers how it works and what it needs to be done to work in a way it should! Put all this against EWI and EWI will always win , head and shoulders ahead . Traditional lime is what I think is best for internal walls.
EWI has failed in many places, but not because of the system, but because of bad execution and wrong decisions. Different areas and different type of buildings have been put in the same category. I have installed EWI on houses, where the bricks were so week, that in places you can't secure the board with the pins, they just crumble, other houses where the bricks were so wet that all you get out is mud instead of dust when drilling. The best thing that EWI does to a house is to protect it from the outside , which reflect the inside thermal loss, undoubtedly . Officially is about 30%, but that depends how good your windows and doors are. Windows are the biggest challenge here. No matter how bad EWI is , is better to reheat dry and not so cold internal brick , than soaked and matching the external temperatures brick. Saying all this, I think EWI is the best insulation system now days. Will it take some improvements? Hell yes, just like everything else!
 
theplasterman said:
Really do find the ewi,iwi,cavity debate interesting..
I'm not as intelligent as alot of you on here especially when it comes to the cavity side of things..
Can anyone tell me why not all three ?
My thick mind tells me that with outside inside and middle done then not alot is going in or out?
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You can't sandwich walls in between insulation as the moisture has to go somewhere, that's why is a no-no to ewi or iwi a cavity filled house

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vfr12 said:
No matter how bad EWI is , is better to reheat dry and not so cold internal brick , than soaked and matching the external temperatures brick. Saying all this, I think EWI is the best insulation system now days. Will it take some improvements? Hell yes, just like everything else!
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Interior insulation isn't affected by moisture content in the walls, and doesn't need to heat up the walls either wet or dry. The benefit to internal insulation is that it isolates the heat source from the heat drain (walls and exterior).

EWI has only one advantage over internal and that's the reduced disruption and cost when installing. That is however a big thing in it's favour, even if it has no bearing on it's ability to insulate.
 
imago said:
Interior insulation isn't affected by moisture content in the walls, and doesn't need to heat up the walls either wet or dry. The benefit to internal insulation is that it isolates the heat source from the heat drain (walls and exterior).
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I was comparing a house with and without EWI , for sure heat won't be so excessive to dry the brick if iwi is installed , sorry if it wasn't clear enough:)

[QUOTE="EWI has only one advantage over internal and that's the reduced disruption and cost when installing. That is however a big thing in it's favour, even if it has no bearing on it's ability to insulate.[/QUOTE]

I love to come back to jobs to see just how things are . Every house has turned the heating on with average 2 months later, that's EWI . Not saying iwi is not worth the money, but I still prefer lime for internal.
 
Ah, I see. Yeah it was the way I was reading it.

As you and @irish_spread have said on a few threads, ventilation is the key to a lot of issues.
 
Iwi has only one disadvantage for me ! It has to come with one of this:D
Sorry it's in German,but you get the drift

 
We have all heard the term a house needs to Breath so internal,external and cavity wall insulation you could say stops it breathing?
 
flynnyman said:
We have all heard the term a house needs to Breath so internal,external and cavity wall insulation you could say stops it breathing?
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Never heard that, but what I heard is the 3 golden rules:D

EWI- stops from sweating
CWI- stops it from pissing
IWI-stops it from farthing
 
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