existing insulation and cavity fill

ctlsleh

Hi,
I was wondering how the existing cavity aeroboard is inserted during initial build. The reason i ask this question is that im getting beaded cavity insulation and availing of the grant, however the salesguy tells me that the existing aerobard is in the middle of the cavity with air on either side and is not held against the inner wall which was what thought it was and therefore they only fill between the aeroboard and the outer wall with the cavity bead fill.

Does this make sense as surely you will still have drafts in between the inner wall and the aeroboard insulation and there will still be heat loss?

would apprecaite any feedback and instruction on how i should tell them to fill it.

Thanks,
Eoin

muffler

ctlsleh wrote: »

I was wondering how the existing cavity aeroboard is inserted during initial build.

Something along the lines of the pic below.

ctlsleh wrote: »

the salesguy tells me that the existing aerobard is in the middle of the cavity with air on either side and is not held against the inner wall

Well he would, wouldn't he? Did he actually see this, did he remove a block from your wall and see it, did he use a camera to inspect the cavity and see it?

ctlsleh wrote: »

and therefore they only fill between the aeroboard and the outer wall with the cavity bead fill.

Thats what they are expected to do although I suspect that he is talking his way out of any possible "comeback" if they did fill properly even at this early stage.

ctlsleh wrote: »

would apprecaite any feedback and instruction on how i should tell them to fill it.

The only instruction you give them is that you want a proper job done. Tell them that you have a friend who does thermal imaging and you will have the walls checked before and after they are insulated and see what he/they have to say.

ctlsleh

Thanks muffler,
so i am correct in thinking that the original aeroboard should be against the inner wall. thats good.
Thanks for the advice on the thermal imaging, ill make sure to do that.
Any wesites you could recommend that I could use to show this if it comes up again?
Eoin

muffler

ctlsleh wrote: »

Thanks muffler,

You're very welcome

ctlsleh wrote: »

so i am correct in thinking that the original aeroboard should be against the inner wall. thats good.

Yes traditionally it would have been the norm (and still is) to fit insulation boards against the inner leaf of the cavity wall. In fairness a lot of it wouldnt have been properly fitted over the years. As it was done by the block layers it was really only slowing them down and a lot of them didnt give it the care and attention it deserved.

ctlsleh wrote: »

Thanks for the advice on the thermal imaging, ill make sure to do that.

Just "threatening" to get this done can get the installers to work that bit more diligently. In saying that it would be a terrific bonus if you actually had the thermal imaging carried out. Can be a little costly though when taken in comparison with the overall cost of the insulation. However It would demonstrate what type of job was done and perhaps show up other areas where improvements be carried out.

ctlsleh wrote: »

Any wesites you could recommend that I could use to show this if it comes up again?

Dont fully understand the question. Do you mean site about thermal imaging? If so google is your friend.

maddragon

I have never seen aeroboard in the middle of a cavity. The pressure of the pumped insulation will force the aeroboard tight against the inner leaf anyway. I would get another company than the one represented by your sales guy.

Poor blockwork and cement in the cavity may have pushed the insulation out a bit from the inner leaf. Pumping insulation in will only help in any event.

ctlsleh

Hi muffler,
Sorry for the confusion, I was looking for a website that shows the insulation should be against the inner wall like the pic in your response. I've been searching for a reputable or regulatory website that shows thatnit should be up against the inner wall on when originally installed (even though we all know that its probably loose), i havent had any luck however so guidance is appreciated.

Re: thermal imaging, when you say expensive, any rough estimations for a 2 story detached hour of 2500 sq ft.

Also would you say €2000 sounds about right for the cavity insulation and attic insulation.

Again, appreciate your view and time.
Eoin

Thanks again,
Eoin

ctlsleh

Thanks mad dragon,
The salesguy said it's held in the middle of the cavity by somecwires or something, I told him that made no sense, but he insisted, I don't think he know his business, so I'm double checking here.
Thx,
Eoin

Poor Uncle Tom

The plans for your house will show the insulation against the inner leaf. The wires he is talking about are cavity wall ties and are designed to keep the insulation against the inner leaf, not in the middle of the cavity.

If your house is over 10 years old it is likely that the space between leafs is 100mm (4") and the insulation is 50-60mm (2"). If the insulation is in the middle of the cavity then it stands to reason that there is only 25mm (1") either side. It is not recommended that you pump a cavity of less than 50mm (2") as there is no guarrantee of fill.

This guy sounds like he is setting the scene to cover a bad job.

MicktheMan

ctlsleh wrote: »

Hi,
however the salesguy tells me that the existing aerobard is in the middle of the cavity with air on either side and is not held against the inner wall which was what thought it was and therefore they only fill between the aeroboard and the outer wall with the cavity bead fill.

Hi Eoin,
Afaik, all iab certs for cavity fill require a cavity inspection (including a borescope survey) to be undertaken, documented and a copy filed in the insulation company's office. This is rarely if ever done, imo.
If there is a gap between the already inplace rigid insulation and the inner leaf of the wall then there is a high risk that by pumping the remaining cavity will have little if any positive insulation effect. The reason being that if the rigid insulation is not tight to the inner leaf then thermal looping occurs between the inner leaf and rigid boards. This thermal looping carries the heat out of the cavity before the insulation has a chance to work.
As PUT & Muffler have said, this sales guy seems to lining up his excuses for poor work.
If I were you I would ask for a copy of the iab cert, ask for a copy of the site assessment including the borescope survey report, ask why he says what he says about the insitu insulation and yes, agree to delay payment until a satisfactory thermal imaging survey has been done (bare in mind that (in my experience) in order to get a definitive thermal imaging survey you need to wait for the colder weather (at the very least a 10 degC differential between inside/outside).

ctlsleh

Thanks Mick,
Ill ask him if he has carried out a borescope, is it part of the requirements before they start the job? ill ask them to do it anyway, i assume that is what you are suggesting?. I had 3 compnies quote, i dont remember them drilling but i think they all looked in the esb box as you can see insulation there, i did measure it myself asnd theres about a 45mm gap between the aeroboard and the outer wall.... i would assume that most dwellings (my house was buillt in 2000/2001) have poorly fitted insulation, is there any guidance on how that can be rectified as pasrt of the beaded fill? or whast i should ask them to do additionallly?
Thanks again to all for their input.
Eoin

MicktheMan

ctlsleh wrote: »

Thanks Mick,
Ill ask him if he has carried out a borescope, is it part of the requirements before they start the job? ill ask them to do it anyway, i assume that is what you are suggesting?. I had 3 compnies quote, i dont remember them drilling but i think they all looked in the esb box as you can see insulation there, i did measure it myself asnd theres about a 45mm gap between the aeroboard and the outer wall.... i would assume that most dwellings (my house was buillt in 2000/2001) have poorly fitted insulation, is there any guidance on how that can be rectified as pasrt of the beaded fill? or whast i should ask them to do additionallly?
Thanks again to all for their input.
Eoin

As example of an iab cert for cavity fill insulation is given here. You will read in section 2.4.1 about the site assessment.

From what you have said, I doubt a proper cavity inspection has been done and whoever told you about the insulation being in the middle of the cavity is covering their a*se.
I would insist on a full cavity inspection being done and to be supplied with a copy of the assessment report. (I had this done myself when I had my own walls pumped).
If there is evidence of poor insulation installation originally then I would seriously question the benefit of going ahead with the beads. The money could well be better spent on other, more effective energy upgrades such as draught/air infiltration elimination.

Roebourne9

I recently got several quotes for cavity and attic insulation and was ready to go ahead with both until a few people told me some disturbing stories bout bead cavity fill causing dampness few yrs down the line, they included an expert who assesses buildings with thermal imaging etc, he also gives recommendations on how to rectify bad insulation jobs, he's in the business 15 yrs n took over from his dad who was in it over 30 yrs. I started researching it on internet and found this article which is exactly they way he described it 2 me, worth reading fully, http://www.askjeff.co.uk/cavity.html I have decided against the cavity fill, my house is 9 yrs old n has aeroboard in cavity. Would put up with some heat loss through walls rather than serious problems in few yrs time

sydthebeat

Roebourne9 wrote: »

I recently got several quotes for cavity and attic insulation and was ready to go ahead with both until a few people told me some disturbing stories bout bead cavity fill causing dampness few yrs down the line, they included an expert who assesses buildings with thermal imaging etc, he also gives recommendations on how to rectify bad insulation jobs, he's in the business 15 yrs n took over from his dad who was in it over 30 yrs. I started researching it on internet and found this article which is exactly they way he described it 2 me, worth reading fully, http://www.askjeff.co.uk/cavity.html I have decided against the cavity fill, my house is 9 yrs old n has aeroboard in cavity. Would put up with some heat loss through walls rather than serious problems in few yrs time

did you read that article?

it specifically refers to damp problems in CWI as being associated with blown fibre insulation. Its a widely accepted view that pumped polystyene beads is the best solution.
Obviously all installations should be done in full compliance with IAB certs

BryanF

Roebourne9 wrote: »

I recently got several quotes for cavity and attic insulation and was ready to go ahead with both until a few people told me some disturbing stories bout bead cavity fill causing dampness few yrs down the line, they included an expert who assesses buildings with thermal imaging etc, he also gives recommendations on how to rectify bad insulation jobs, he's in the business 15 yrs n took over from his dad who was in it over 30 yrs. I started researching it on internet and found this article which is exactly they way he described it 2 me, worth reading fully, http://www.askjeff.co.uk/cavity.html I have decided against the cavity fill, my house is 9 yrs old n has aeroboard in cavity. Would put up with some heat loss through walls rather than serious problems in few yrs time

I would accept some of his points but have a slightly different angle of attack here , maybe somewhat biased (as an Arch tech who has a small bit of a grasp of building science).

he talks about ewi: I would question whether this should be done with out filling the cavity..
he also mentions Internal insulation as a solution: I would be reluctant to do this for a number of reasons that I'm sick of explaining
The picture seen here is mineral-wool fibre,so this is not what is now generally used..
There are horror stories of crap jobs and even worse installers selling in appropriate products and installs and this imho is the real issues moving forward:

• we have a self certification system in Ireland which does not require, reward or demand professionals to supervise, provide insurance or stand over the work of the installer (in this case many can just do a week long course and pay to be a certified installer)

• in actual fact an installer can come along and sell you any product with no overseeing professional, other than the NSAI which only approves the product, but does not oversee its installation.
• there is no real come-back or process of suing the installer.. other than the guys getting struck off the grant installer list..

much of the expertise required (engineers, architects & arch techs) to spot unsuitable installations are having to leave the country, even thought the government a has pledged a substantial amount of money at grant retro-ftting insulation and many of measures are financially worth while for the home owners.

so I would suggest that there are suitable products on the market to use in the cavity, but that if you are concerned about dampness and other future issues: employ a professional to insure the house is suitable for the process, and there are no other underlining issues and that the correct install and product is used.

Roebourne9

Did u read the Full article sydthebeat?

It's not specific to mineral wool as u seem to think,
it goes on to talk about bead fill which i was referring to and says about the damp problem with voids due to various reasons and other problems too, that's why I suggested it be read in full.

sydthebeat

sydthebeat wrote: »

Obviously all installations should be done in full compliance with IAB certs

i did read it fully.

the vast bulk of the article is an examination of mineral fibre blown insulation. it goes on to recommend better products including beads.

as you can see from my post above, the success of the installation is dependent on compliance with the certificates. The 'worries' listed regarding beads are all examples of the product not being installed in accordance with certificates.

i wouldnt drive my car with no oil.... nor would i install any product without complying with the certificate that certifies performance.

Roebourne9

Well, if what Bryanf has to say is anything to go by iab certs would really fill me with confidence,

BryanF

Roebourne9 wrote: »

Well, if what Bryanf has to say is anything to go by iab certs would really fill me with confidence,

I think you've misunderstood my rant yesterday:):

BryanF wrote: »

I would suggest that there are suitable products on the market to use in the cavity, but that if you are concerned about dampness and other future issues: employ a professional to insure the house is suitable for the process, and there are no other underlining issues and that the correct install and product is used.

as Syd stated

sydthebeat wrote: »

all installations should be done in full compliance with IAB certs

its not the certs that are the problem its how & who interprets and uses the product correctly...

Poor Uncle Tom

BryanF wrote: »

as Syd stated its not the certs that are the problem its how & who interprets and uses the product correctly...

Sometimes the certs don't go far enough.

ctlsleh

Poor Uncle Tom wrote: »

BryanF wrote: »

as Syd stated its not the certs that are the problem its how & who interprets and uses the product correctly...

Sometimes the certs don't go far enough.

All very interesting comments, does anyone have a cheat sheet of questions that one should be asking the installers before they start the job, that will keep them on their toes and more likely to complete the job properly?

Roebourne9

BryanF wrote: »

• we have a self ce:)rtification system in Ireland which does not require, reward or demand professionals to supervise, provide insurance or stand over the work of the installer (in this case many can just do a week long course and pay to be a certified installer)

• in actual fact an installer can come along and sell you any product with no overseeing professional, other than the NSAI which only approves the product, but does not oversee its installation.
• there is no real come-back or process of suing the installer.. other than the guys getting struck off the grant installer l

much of the expertise required (engineers, architects & arch techs) to spot unsuitable installations are having to leave the country, even thought the government a has pledged a substantial amount of money at grant retro-ftting insulation and many of measures are financially worth while for the home owners.

so I would suggest that there are suitable products on the market to use in the cavity, but that if you are concerned about dampness and other future issues: employ a professional to insure the house is suitable for the process, and there are no other underlining issues and that the correct install and product is used.

when you say about self certification does that go for the iab certified people, and your point about no comeback, when a certified company give a warranty with the installation It's pot luck as to whether they will fix any problems that may occur?

It was one of those professionals that warned me off the cavity fill. If It's relevant my house was built in 2002 and has aeroboard in the cavity. For me anyway until these certified companies include as part of the deal, thermal imaging of before and after or whatever they have to do to prove they have done the job properly without voids etc I will wait.
Not 1 of the companies I got quotes from offered that service even at an extra charge and they were all iab certified reputable companies, and on seai list. unfortunately at the time I got the quotes I hadn't heard about potential problems as I would have brought it up with them.

BryanF

Roebourne9 wrote: »

Not 1 of the companies I got quotes from offered that service even at an extra charge and they were all iab certified reputable companies, and on seai list. unfortunately at the time I got the quotes I hadn't heard about potential problems as I would have brought it up with them.

but their not going to offer you thermal imaging they are not required to, and even if they did would believe them? this is a sizeable investment would you not get someone independent to specify and check it?

Roebourne9

BryanF wrote: »

but their not going to offer you thermal imaging they are not required to, and even if they did would believe them? this is a sizeable investment would you not get someone independent to specify and check it?

Yea good point, was going 2 wait till that friend of mine who's doing that work in UK is here and get advise from him anyway, He has all the equipment 2. I presume getting attic is straight forward enough, It's a dormer so been told even if we went 4 both we wouldn't get grant.