Bonded Beed Cavity Wall Insulation

Quazzie · 09-02-2009 10:35PM

gizmo555 wrote: »

Less installation time, but not half the installation time. Travel time, time taken to drill holes and time taken to make good the holes are the same whether the cavity is half filled or completely filled. Other costs, such as sales, office and administration overhead, insurance, etc. would also have to be taken into account.

All in all, I would have to agree that your comment that half filling a cavity with bead should cost exactly half the price of completely filling a similar cavity is at best grossly simplistic.

My dad is currently building his own house and is going for a 150mm cavity filled with pumped bead and he asked the company supplying the pumped bead whether it was much difference betweent the price of the 100mm cavity and 150mm cavity and they told him there was no difference and he was given the 150mm fill for the price he was quoted for the 100mm. I think this was solely because they were eager for sales but he was told by the sales guy that the price of the beads is cheap and thatits the labour thats the majority of the price.

RKQ · 09-02-2009 10:53PM

gizmo555 wrote: »

OK, I've already asked you in another thread and I'd like to ask you again here please - what risk are you talking about? And if there is a substantial risk, why has the government just decided to grant aid precisely what you believe is far too risky?

I've given my opinion above. IMO there is a substantial risk.

Why bother building a cavity wall if you are going to fill the cavity with bead?
You no longer have a cavity wall or the advantages of a cavity.

The Government grant aid alot of things. This does not mean that the product is ideal - just that it is financially viable. Filling the cavity is a cheap and quick way to insulate old houses.

The Government give much bigger grants to Externally insulate a wall or Internally dry-line a wall. By your logic these options are better and I'd agree with that logic, unfortunately external or internal insulation is much more expensive.

I suppose you get what you pay for! IMO full cavity fill insulation is a bad option.

gizmo555 · 09-02-2009 11:24PM

RKQ wrote: »

I've given my opinion above. IMO there is a substantial risk.

Sorry, I am not being deliberately obtuse, but as far as I can see you've stated three times that filling a cavity wall with pumped insulation is risky without ever giving any explanation as to what the nature of this risk is.

I would genuinely like to know. My interest is as a homeowner who is considering having a wall with a 110mm cavity, which already has 60mm of rigid insulation, pumped with bonded bead to fill the remaining 50mm gap. This is what I've been advised to do by a BER assesor, who is also a professional engineer. If there is a genuine problem with following this advice I'd like to know about it.

As for the options of dry lining or externally insulation, I had a vendor of an external insulation system look at my house and he advised that while it could be done, it would be vastly more expensive (10x plus) and he recommended cavity insulation too, even though he doesn't sell it himself. He said his system is more suitable for older houses with no cavity, like my last house built in 1940 and which had solid mass concrete walls. As I understand it, grants are being made available for drylining or external insulation for cases like this, where cavity insulation is not possible. Dry lining has other problems apart from cost, it reduces habitable space and is much messier and disruptive to install.

RKQ · 10-02-2009 12:38AM

I can only give my honest opinion. Its risky because the cavity is full, therefore water that penetrates the external leaf can cross the cavity via the "fill" and penetrate the inner wall.

I have seen this happen when there is mortar on a wall tie. I know that these insulants have an IAB cert and are safe to use but they are relatively new and only time will tell. A house is suppose to last 50 years, no house has had full cavity insulation for 50 years. Truth is nobody is really sure what happens to it over time.

The cavity was developed in our damp wind driven rain, out of necessity over the last hundred years. Damp proof courses, cavity tray etcs were developed so that the external wall can be wet but this water can not travel to the inner leaf.

If you fill the cavity then you are depending on your external render to keep you walls dry. One hairline crack is a potential water penetration risk.

How water-proof can aeroboard or rockwool be? Have you left either material out in the open air for a length and time? Most things deteriorate over time, when wet.

All clay brick soaks water. Water penetrates brick. Houses with half brick fronts, brick arches or brick quoins should not use bead or rockwool.

Your case in particular is difficult as its likely you already have high density foil backed insulation in your cavity. These boards are unlikely to be perfectly plumb. It will IMO be very difficult to pump a consistant 40mm of insulation into your cavity.

IMO internal insulation would be much more beneficial. Pumped insulation is a "magic bullet" at the moment. It is incredibly cheap and very cost effective but it is not without risk.

The jury is out. Time will tell. If it does allow water penetration, then it will be almost impossible to remove it from the cavity.

If you can get a 10 year absolute guarentee from the manufacturer then take a chance - if you can't get a guarentee then really think about your options.

gizmo555 · 10-02-2009 11:15AM

RKQ wrote: »

I can only give my honest opinion. Its risky because the cavity is full, therefore water that penetrates the external leaf can cross the cavity via the "fill" and penetrate the inner wall.

This is in direct contradiction of the IAB Agrément certificates for these products, e.g.:

4.2 LIQUID WATER PENETRATION
4.2.1 Test data obtained by the NSAI Agrément confirms that a masonry wall incorporating [Some Bead Product] Cavity Wall Insulation and built to the requirements of IS 325: Part 1: 1986, will not transmit water to the inner leaf.
4.2.2 Test data obtained by NSAI Agrément also demonstrates that [Some Bead Product] Cavity Wall Insulation material does not absorb water by capillary action. Water which penetrates the outer leaf of the wall will drain down the cavity face of the outer leaf. When the product is used in situations where it bridges the dpc in walls, dampness from the ground will not pass through, provided the cavity is taken down to at least 150 mm below the level of the lowest dpc.
4.2.3 [Some Bead Product] Cavity Wall Insulation System, when used in accordance with this Certificate, present no significant risk of water penetration.

RKQ wrote: »

I know that these insulants have an IAB cert and are safe to use but they are relatively new and only time will tell. A house is suppose to last 50 years, no house has had full cavity insulation for 50 years. Truth is nobody is really sure what happens to it over time.

Isn't this precisely the type of situation the Agrément system is supposed to address? As it says on the IAB website:

Agrément certification is designed specifically for new building products and processes that do not yet have a long history of use and for which published national standards do not yet exist.

To follow your logic to its conclusion, no-one should use any construction material or technique less than 50 years old.

RKQ wrote: »

If you fill the cavity then you are depending on your external render to keep you walls dry. One hairline crack is a potential water penetration risk.

Again, this is in direct contradiction of the IAB Agrément certificates for these products

RKQ wrote: »

Your case in particular is difficult as its likely you already have high density foil backed insulation in your cavity. These boards are unlikely to be perfectly plumb. It will IMO be very difficult to pump a consistant 40mm of insulation into your cavity.

My existing insulation is unfortunately not foil-backed. I agree it is a major drawback of pumped insulation that you can't directly see the finished job to ensure there is full coverage. It is therefore very important to get a reliable contractor - I'n sure the new grant scheme will bring plenty of cowboys out of the woodwork. The Agrément certs are only valid if the products are installed in the ways outlined in them. One could also have a thermal image survey done afterwards to check for gaps, but this is an extra cost - I've been quoted €500. This, however, is a separate issue from any possible risk that the pumped insulation might cause damp.

RKQ wrote: »

If you can get a 10 year absolute guarentee from the manufacturer then take a chance - if you can't get a guarentee then really think about your options.

This is good advice, but I suppose the problem is the guarantee is only as good as the manufacturer offering it. If they go belly up, so does the guarantee. It's a pity there's no Irish scheme like The Cavity Insulation Guarantee Agency in the UK (www.ciga.co.uk), effectively a mini-Homebond scheme for cavity insulation offering an independent 25 year guarantee. Still, the fact that such a long guarantee is even available there, for methods and materials identical to those used in this country, must be some reassurance.

RKQ · 10-02-2009 11:44AM

gizmo555 wrote:

4.2 LIQUID WATER PENETRATION
4.2.1 Test data obtained by the NSAI Agrément confirms that a masonry wall incorporating B]Some Bead Product[/B Cavity Wall Insulation and built to the requirements of IS 325: Part 1: 1986, will not transmit water to the inner leaf.
.

Why persue me for my opinion, if you are so well informed and you obviously have your mind made up?
Are you an Installer? (The 90% of your posts to date are about Cavity fill insulation)

Can you address water penetration in brickwork and state how you will ensure compliance with I.S 325: Part 1:1986.

gizmo555 wrote:

Again, this is in direct contradiction of the IAB Agrément certificates for these products.

You asked for my opinion 3 times! Now you want to poke holes in it.
An IAB cert clearly states that a material will work if its installed in accordance with the IAB cert. You are being subjective in the parts of the cert you are quoting.

gizmo555 wrote:

My existing insulation is unfortunately not foil-backed
.

Why not?
60mm Aeroboard when out 6 years ago! Circa 2002, I thought your house was recently built?

gizmo555 wrote: »

This is good advice, but I suppose the problem is the guarantee is only as good as the manufacturer offering it. If they go belly up, so does the guarantee. It's a pity there's no Irish scheme like The Cavity Insulation Guarantee Agency in the UK (www.ciga.co.uk), effectively a mini-Homebond scheme for cavity insulation offering an independent 25 year guarantee. Still, the fact that such a long guarantee is even available there, for methods and materials identical to those used in this country, must be some reassurance.

This is not the UK. We have more rainfall.
We do not have District Surveyors / Building Control Officiers that inspect the full construction. (If we did, you'd have foil kingspan in your walls)

Of course you could get a UK company to install it and take their 25 year guarantee! Or they might think its too wet here!

Lets keep it simple and clear - I would never use full fill cavity insulation, far too risky, especially if you already have a partially filled cavity.

I believe that full fill cavity insulation will be the "asbestos" of the future.

There is no point in building a cavity and then filling it - that totally defeats the purpose of the cavity!

I'd live in a tent before I'd touch the stuff - thats my opinion, take it or leave it

gizmo555 · 10-02-2009 02:04PM

RKQ wrote: »

Why persue me for my opinion, if you are so well informed and you obviously have your mind made up?
Are you an Installer? (The 90% of your posts to date are about Cavity fill insulation)

I pursued you for your opinion because I was genuinely interested in it. You stated a number of times pumped cavity insulation was risky without explaining what risk you meant. Now you have. Thank you! (BTW, I am not an installer - as I said, I am merely a homeowner.)

I'm no better informed than anyone could be through the use of Google. I'm researching this area before taking a decision and discussions here are part of that research. Hence most of my posts are on this topic.

In fairness to you, I have found one other writer who is just as adamantly opposed to pumped insulation, Jeff Howell of the Daily Telegraph. Here's one piece he wrote:

http://www.telegraph.co.uk/property/3346244/On-the-level-should-I-insulate-my-cavity-walls.html

Google his name and "cavity insulation" and you'll find much more.

RKQ wrote: »

You asked for my opinion 3 times! Now you want to poke holes in it.

I asked you to clarify it 3 times. Now you have. Thank you! When you made clear that the risk you had in mind was water penetration I just pointed out that your views are contradicted by the IAB certs referenced.

RKQ wrote: »

An IAB cert clearly states that a material will work if its installed in accordance with the IAB cert. You are being subjective in the parts of the cert you are quoting.

I have made precisely this point several times already, e.g:

gizmo555 wrote: »

The Agrément certs are only valid if the products are installed in the ways outlined in them.

I don't agree that I'm being particularly subjective, but I at any rate did provide a link to where the certs can be downloaded and read in their entirety by anyone interested.

RKQ wrote: »

60mm Aeroboard when out 6 years ago! Circa 2002, I thought your house was recently built?

It was built in 2000 - I guess, from what you say, a couple of years before the foil-backed product you mention came into general use.

RKQ wrote: »

This is not the UK. We have more rainfall.

Northern Ireland is part of the UK and is covered by the guarantee scheme mentioned.

RKQ · 10-02-2009 02:50PM

I have given my opinion. As the saying goes, "Doctors differ, patients die".

Jeff Howell and I are not the only ones. The risk exists.
The jury is well and truly out.

I wouldn't put it in my cavity wall.:D:D:D

Slig · 10-02-2009 03:25PM

I think the options for retrofit insulation are limited. Personally I am very concerned about the attitude towards insulation in todays society. There seems to be huge emphasis on getting the best U-values for your wall and the only concern seems to be how much insulation you can pack into it.

Dry-lining or internal insulation is not an ideal solution, it causes damp and mould growth if done wrong, something we will see alot of in the near future.

Cavity fill insulation can also lead to moisture ingress. I know that the IAB certs say that moisture will not transfer across the beads but what about the gaps and air voids that will enevitably be created around wall ties etc.

There are alot of opinions being bandied about by people about ideal wall constructions, everybody has an opinion. Unfortunately in todays energy crisis climate most of the methods being used today are experiments.

gizmo555 · 10-02-2009 05:34PM

Slig wrote: »

There are alot of opinions being bandied about by people about ideal wall constructions, everybody has an opinion. Unfortunately in todays energy crisis climate most of the methods being used today are experiments.

Guys, I fully accept the sincerity of your views. However, having delved a bit deeper into the British Board of Agrément's website (www.bbacerts.co.uk), the earliest certification I can find there for pumped cavity insulation dates back to March 1987 - just short of 22 years ago! (This is for a bead product first certified in 1987 and with a revised certificate taking account of new building regs issued in 2007.)

How long, in your opinion, does a construction technique or material have to be in use before it's no longer considered novel or experimental and "the jury comes back in"? If 22 years isn't long enough, how long is?

muffler · 10-02-2009 06:39PM

gizmoo555 you have made your point and I am at a loss to see why you are pushing this.

The guys give their opinion, an opinion they are entitled to just the same as you are entitled to yours. You have done your research and you have sought and been given advice here so now its time for you to make up your mind.

gizmo555 · 10-02-2009 08:05PM

muffler wrote: »

gizmoo555 you have made your point and I am at a loss to see why you are pushing this.

The guys give their opinion, an opinion they are entitled to just the same as you are entitled to yours.

Well I guess you can put it down to "Comment is free, but facts are sacred." I'm, as I say, researching the issues and soliciting opinions on the forum here, but that doesn't mean I have to blindly accept any opinions offered without challenging their factual basis.

RKQ after repeatedly saying that cavity fill insulation is risky without explaining why, finally gave it as his opinion that there is a risk that water will cross the insulation to the inner leaf. It is a fact that the Irish and British Agrément boards - having carried out appropriate testing - agree that this will not happen where these products are correctly installed.

Both RKQ and Slig describe these products as "relatively new" and "experimental". It is a fact that they have been in use for about a quarter of a century - they are not in any meaningful sense novel or experimental and there has surely been ample time to assess their long-term performance in the field.

I'll leave it at that . . .

RKQ · 10-02-2009 08:21PM

gizmo555 wrote: »

Well I guess you can put it down to "Comment is free, but facts are sacred." I'm, as I say, researching the issues and soliciting opinions on the forum here, but that doesn't mean I have to blindly accept any opinions offered without challenging their factual basis.

Very strange, you continue to ask for an opinion, once you hear it you go to great lengths to prove a person wrong.

Nobody has backed up your "theory" or quotes. If you want to use it and you know the risk, then go and used. Gamble your home!

I'd never use full fill cavity insulation in a cavity wall - it defeats the purpose and carries a risk of water penetration. That my last word...:D

Bonded Beed Cavity Wall Insulation

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