Advice please : External Insulation versus ??

The previous two post read:

Quote:
Originally Posted by sas
Yes, but I'm one of those people that believes the idea of externally insulating anything other than block makes no sense whatsoever.

When I hear EWI, I picture blocks with oil based insulation stuck to them.

As do I

There are many more choices out there, alas not cheaper than EPS. Mineral based foam or fibre insulation, vacuum panels, sheep- and cellulose wool and so on.

The cheapest method is usually not the longest lasting. And an ammortisation must be - unless one wants to waste energy.

If a method is described as "energy saving" the ammortisation of the investment has to be met. Plus some energy savings to follow the ammortisation, of course.
The sum would result in a guarantee of X-years life time.

I still haven't found an EWIS sold or installed in Ireland with any life time guaranteed by the manufacturer.
The only life time guarantees I have seen so far are the EU continental ones. But these continental EWIS (the very same as sold in Ireland/UK as well!) are excluding wind forces as seen on the official Irish weather map.

And Irish specifiers are very tight-lipped when it comes to their own guarantee. See this thread.

Like selling pain killers to fight cholera.

The only life time guarantee demanded for subsidised energy 'saving' meassures (for material and workmanship) seems to be demanded when retrofitting ST energy. 5 years if the taxpayer has to fork out.

See

http://www.seai.ie/Grants/Better_energy_homes/Code_of_Practice_and_Technical_Specification.pdf

For guarantee demands check the end of the document, last two or three pages.

And ST isn't saving any energy at all.....but a 5 year warranty/guarantee has to come with it. Absurd.

No such guarantee is demanded for the rest of the taxpayer drainage program, like boilers and insulation. Take it and keep it, no matter how long it performs or not.

BryanF wrote: »

... while there are lots of good installers out there, IMHO they are going to do what's easiest for them and not always whats best for the building

Your definition of good and mine clearly differs then! I promise I'll stop taking issue with your posts BryanF

I will speak to my experience with EWI companies. I went into detail with 3 companies for my own home. All looked ok until I got closer to being ready to start.

Company A fell to the side when they sent me to see a site by a preferred installer. It was rough shall we say. The salesman was fully aware that I am shooting for certified passive and recommended that I visit this site. He got an earful off me later. I also learned afterwards that their "training" consisted of 1 day with half of it being on site safety and u-value etc and the rest being a demonstration of the materials i.e. no trainee touched any EWI materials while on training. I learned this through a friend of mine who did the training with the intention of doing his own home. This is actually where it gets worse. The company in question was fully aware that my friend was only their for his own home and had NO construction background or experience. A few weeks later he got a phone call from the company wondering if he'd be prepared to take on a job for them because they had no installer in that area!

Company B fell by the way side based on their guarantee. They have a 10 year insurance backed guarantee on their system. The problem is that the insurance mandates that the IAB cert detailing be followed. As passive details require good thermal detailing and the IAB cert doesn't (basically), they wouldn't give me the guarantee using details outside the cert. This is all well and good but they'd known for months that the detailing was different. It looks like they basically were hoping I'd stop asking questions. I only ever got to speak to their salesman, their technical people showed little interest. Plus the installer I intended using turned out to be not up to the job, much to his protests otherwise!

Company C therefore were a breath of fresh air. I spoke to their salesman once. A few days later the salesman, their technical manager from dublin and a recommended installer were on site to see what was involved. They told me that certain things I'd planned on doing where out (and with good explanations why) and gave me details that they'd be happy to do that give me what I was looking for. Once my windows were installed they (all 3 of them) came on site to inspect the installation detail. This was where they really came into their own because they pointed out that the end caps for my aluminium cills were not the recommended type for EWI. Since then I've been at war with my window company about the end caps but that's for another day. I will underline that I've paid no deposit to this company yet and they are still being very responsive. They are a very large german company. They are costing me more on the job than some of the other quotes. I am more than happy to pay it however based on what I've experience so far. I will report back on how the job actually goes in a few months time. The warranty they offer is less than inspiring however, 5 years materials only. I do however need to trust in NSAI certification (to a certain extent).

I have no intention of telling anyone who A and B are, either by PM or otherwise. People must do their own due diligence. All 3 are IAB certified however.

There will be plenty who think I am foolish ( saved you some typing there Heinbloed ) and truth be told I'm not convinced that's not true. I am however committed to this path as I've block on the flat and no other option now. The only safe option in the majority of Irish peoples eyes (and I will include construction profressionals of all types) is our traditional partial fill cavity. I wouldn't be uncomfortable suggesting that even amongst our small group of moderators there is a big difference of opinion on what is the best option. If I was starting again a wide cavity would be damn attractive.

I've rambled on for long enough...

BryanF wrote: »

good stuff, ramble away.:)

would company C begin with a W?

SAS Please send me your preferred company name and tell us more about the
alu cill pitfalls

"W" didn't even make the 3. At the time they were all metal profiles and not interested in doing PH detailing so I never went any further with them.

PM away.

For the rest of you in the industry....

Company C
- 1 syllable
- Sounds like "Snow".


On the alu cills I intend doing a detailed write up for the forum on this, pictures etc. To say I'm p***ed off over this is the understatement of the century! I'd like the good people here to be well informed and learn from those of us currently taking the plunge. Give me a few days.

BryanF wrote:

the ridged mineral wool board or timber fibre board works (used mainly on old pre conc block walls), and I know you can go for a rainscreen, but can an EWIS provide a breathable render finish?....

Banned now in many countries, USA, Canada etc...

See also page 473 on this mighty document:

http://www.byg.dtu.dk/upload/institutter/byg/publications/rapporter/byg-r189i.pdf

and

http://www.ibp.fraunhofer.de/Images/K%C3%BCnzel_2008_Influence%20of%20rain%20water%20leakage%20on%20the%20hygrothermal%20performance_tcm45-86537.pdf

The same goes for any wicking material. Disaster is the consequence.

rockwool and silicate render?

The mineral wool can take up water as we know. And this water can freeze. Causing an abnormal heaving, weakening the structure.
Once frozen the moisture still penetrating the wool from the house will increase the thickness of the frozen lump/layer. Adding to weight and volume.

Here wufi would be the only answer, with ample of leeway for frost situations, clear nights and high moisture loads.

Problematic is future treatment of the mineral rendered walls, once painted with a diffusion tight paint the moisture will be locked in for good.

(Mineral and plastic) renders allow water to condense at the outer surface, thawing of ice and dewing of airborne moisture will happen both on their surface. Whilest the render is prepared to survive this the wool can not get rid of the internal moisture if covered with a layer of ice (frozen render).

And with temperatures deep enough to freeze the entire layer of render the interstitial moisture can form ice within the wool, see above and also the links.

These are theoretical problems which had rarely been seen in situ. But they do exist.

A breathable, thick render is the remedy. And of course the avoidance of ice formation on the external surface. For example with the aid of cladding (rain, dew), a wide roof overlapping the wall (cold sky).

The thickness of the render increases it's resistance to freezing, simply because of it's thermal storage capacity. But this results only in a delay, it won't be a total protection.

The thinner the render,the less thermal storage capacity it has and the less breathable it is the higher the risk of freezing temperature within it.
1 Kh (Kelvinhour)of difference means a lot here when delaying the freezing.
Frozen renders do not allow water to pass through it, first they have to thaw themself.
With longterm freezing in very dry air (for example seen with continental winters) the ice within the render can dry as well. Freeze drying it is called.

The issue is complex, so better use wufi or some other simulation program.
And play safe, as said: protective meassures are not difficult to install. But have their limits as well.

Since there is a good reason why hollow block concrete walls fail and cavity walls where invented the question arises what driving rain loads EWI can take resp. to what load it is exposed to.
So my question to our weather specialists and civil engineers and those who have some sources of knowledge:

What are the 'driving rain loads' in Ireland?

From my own observations these are considerable higher compared to the EU continent, more wind and more rain for sure.
Kuenzel mentions them here in this document, chapter 3.1, see also table1 for comparrissons:

http://www.ibp.fraunhofer.de/Images/K%C3%BCnzel_2008_Simulating-Water-Leaks-External-Walls_tcm45-86534.pdf

Whilest Kuenzel publishes the anual loads there is no reference to peak loads, to liters per hour during a specific season (winter, summer).

Are the 'test regimes' of IAB and NSAI taking into account the driving rain loads? Based on which data? With how much of leeway, limits, peak loads?


Is any Irish-certified EWIS manufacturer guaranteeing his products for the Irish driving rain loads? Any links? I couldn't find any data on guarantees from them at all, maybe I've checked in the wrong corner....


Thanks.

Podgee's post is taking shape.

In his/her second post the target of the effort is described as

a reasonably energy efficient house that doesn't cost the earth to heat.

.

And moderator Sydthebeat answers with

internal insulation will always be inferior to external because of the obvious problems of thermal bridging.

And I digged out the failed German/USA/Canadian cases of EWI.....

Anyone with an Irish longterm experience of EWI(S)?

The lack of thermal bridging seems to be the weakness of some of the contemporary EWI methods - where the exterior is getting wet AND cold. And therefore fails expectations.

The Austrian association of brick manufacturers condemns the PHI for over-insulating houses, the U-values being to low to be sustainable, the energetic concept to fragile. Better heat a bit extra and safe the energy to demolish and re-build. So they say.
Not that a PH can't be build with bricks-or monolithic walls as such- but solar houses 'wasting' thermal energy through the brick walls seem to have a better energetic ammortisation. Fraunhofer institute agrees on this b.t.w..

And solar houses save on the "exhorbitant prices for HR ventilation systems" - (quoting Dr.Feist from the PHI !)..... by simply wasting the thermal energy contained in the stale air, dumping this energy. One opens the window for ventilation, let's out stale air and does NOT get back mould spore infested air. Fresh air that is.

Food for thought?

The Irish idea of stack ventilation in combination with a never ending supply of ST energy combined with walls lasting for generations - that's it.
Provided the price is right. Up to the drawing boards.

Or buy one, ready made, off-the-rail for a designer's price:

http://www.aecb.net/forum/index.php/topic,2986.0.html

Meteireann has published a map based and calculations, not very precise but useable.It gives an indication what to expect on an average base.It's published only since November 2010.

See:

http://www.met.ie/climate-ireland/Driving%20Rain%20Index.pdf

Rainfall driven against a wall may be partially absorbed if the wall is porous or may penetrate
through cracks in the wall. The effects of rain on a building are related to the speed of the
winds and the intensity of the rain. The Driving Rain Index is the product of the Average
Annual Rainfall and the Average Annual Windspeed.

It would be very usefull to see data gathered for peak loads (mm driving rainfall during strong winds) in winter times, to check the risk of freezing EWI surfaces.

The tiles/half bricks glued to EWI seem to be very prone to frost demage. "Traditional looking fascades" - stipulated by planning conditions or phantasied by designers - in combination with EWI seems to be a no-go for our country.

BrianF wrote:

so its how to ensure you achieve durability, flexibility and adding an inhibitor to stop microbial growth on the render...

Which inhibitors have you used so far, BrianF?