Green Building Forum - Article challenging the benefit of breathability Wed, 03 Jun 2026 06:08:33 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64231#Comment_64231 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64231#Comment_64231 Fri, 16 Oct 2009 13:19:46 +0100 Peter Clark
Posted By: TunaSo, breathability does not prevent building failure through gross leaks.


Posted By: Peter ClarkNo, but it is designed explicitly to help deal with such leaks.


Still re reading all this!

just wanted to amend my response:

Breathability cannot prevent gross leaks of course.

But breathability is intended exactly to prevent building failure through gross leaks, as well as through less gross leaks.

Peter]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64234#Comment_64234 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64234#Comment_64234 Fri, 16 Oct 2009 13:32:39 +0100 fostertom
Cambridge paper yes, plus any others]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64235#Comment_64235 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64235#Comment_64235 Fri, 16 Oct 2009 13:32:46 +0100 davidfreeborough
If you're using breathable sarking membrane then it makes more sense to ventilate the batten cavity. This way the sarking membrane protects the insulation from the wind. The belt and braces approach would be to use PUR below the rafters & something vapour open between them. My preferred sloping ceiling is, from the inside:

12.5mm Fermacell;
0.3mm polyethylene VCL, laps & edges taped (530MNs/g);
9mm OSB3 lining board (2.2MNs/g);
400mm Crown Rafter Roll 32 between 400mm Masonite rafters;
22mm Pavatex Isolair woodfibre sarking board (0.55MNs/g);
Tyvek Supro Plus sarking membrane, laps & edges taped (0.17MNs/g);
38mm counter battens, 25mm vent to eaves, 5mm vent to ridge;
25mm tile battens.

David]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64237#Comment_64237 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64237#Comment_64237 Fri, 16 Oct 2009 14:00:26 +0100 Mike George
The job on which the condensation occurred was a simple cold roof scenario with horizontal insulation above conventional plasterboard ceiling. It occured before the tiles were laid. Perhaps some 'freak' weather conditions caused this to happen but seeing condensation on something which is supposed to be breathable rather knocks one's confidence in it.

I don't see any problem with your construction at all other than it is extremely more expensive than mine. This not just due to the material cost, but to space/structural requirements resulting from the extra volume necessary to contain it.

In short, if there is any benefit, it is not worth the extra cost [to me] For those who have the luxury of being able to afford more 'natural' products then good for them]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64239#Comment_64239 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64239#Comment_64239 Fri, 16 Oct 2009 14:03:13 +0100 Mike George Posted By: fostertomMikeG, I'm coming to that asap!

Cambridge paper yes, plus any others

So anything [peer reviewed or otherwise] which does not fit with your point of view on how vapour 'behaves' is wrong?]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64241#Comment_64241 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64241#Comment_64241 Fri, 16 Oct 2009 14:28:34 +0100 davidfreeborough
So how about:

12.5mm plasterboard;
0.3mm polyethylene VCL, laps & edges taped;
30mm PUR below rafters;
150mm Crown Rafter Roll 32 between 150mm rafters;
Tyvek Supro Plus sarking membrane, laps & edges taped;
38mm counter battens, 25mm vent to eaves, 5mm vent to ridge;
25mm tile battens.

This has a slightly better U value than the all PUR approach (0.16 versus 0.17) and is probably lower risk in terms of condensation. The ventilated batten cavity would be seen by some as belt and braces, but you could see it as insurance against moss filling the gaps around the tiles. Would this cost any more than you're currently paying?

David]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64243#Comment_64243 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64243#Comment_64243 Fri, 16 Oct 2009 14:46:51 +0100 Mike George

Posted By: Peter Clark

The general problem is that IF some water gets in to that construction it may be hard to get out again. That might be all right too, depending on how much gets in and where.


Significant water getting in from above would show itself [somewhere] quickly. Smaller leaks would not affect the construction as the surface area of rafters exposed is such that a high level of ventilation would be adequate to ensure such water would evaporate and be vented away.

Any water vapour which migrates from the internal environment would also be vented in the same way.


Posted By: Peter Clark

If a tile slips and is not noticed for a while, water could run onto the breather and through into the rafter/insulation.


No, if the breather membrane is undamaged and correctly lapped, no water will get in.

Posted By: Peter Clark

Might the damp have a detrimental effect on the rafters? If the insulation in between and below the rafters was hygroscopic, it would protect the rafters. If it had good capillarity, the water could run throughout the structure and not pool. If it was very vapour open in addition, it could dry out faster. This would happen especially if the 5:1 ratio of vapour openness was present.



I don’t believe the moisture necessary to cause such damage can remain hidden within fabric which is ventilated in the way I proposed. Dry rot for example, requires a certain temperature range and moisture content, as well as a distinct lack of ventilation. Ensuring any one of these three things does not happen will make dry rot impossible- One will of course try to ensure all three but the presence of sufficient ventilation is enough to avoid problems resulting from non visible leaks. No need to go to the extent [and cost] of the 5:1 ratio, which no doubt works equally well [not withstanding the debated effect on internal ‘health and well being’

Posted By: Peter Clark

If a hole is created in the plaster/vapour barrier, eg by picture hooks, water vapour could be getting in there, at a very low rate, but maybe continuously, day and night, for months on end, each year, year after year.



This may happen, depending on internal conditions but is unimportant due to my ventilation comments above.

In general, the risk of humidity levels being high enough to cause significant risk of interstitial condensation are exaggerated in my opinion. Bedrooms for example do not continually ‘force’ water vapour into the fabric in a way suggested by some. It’s complete rubbish.

Posted By: Peter Clark

A sloping ceiling/roof is probably the safest bet, as I am sure you were aware when you chose it. What about the same kind of construction for a wall – with electrical sockets and service penetrations through to the outside?



I don’t like timber framed walls personally, due to the risk of someone somewhere along the line getting it wrong. Obviously there is nothing wrong with it when it is designed correctly and installed as such. Unfortunately, the complexity of the 5:1 design style makes problems more likely in my opinion. Masonry on the other hand, is easier for everyone to design and build at least in terms of basic weathering and hence durability. Correct installation of insulation however is another argument, which is why I use partial fill PUR, and rigorously inspect things as they are done. I wonder how many realise that such inspection is now a requirement under Part L of the building regulations?

To answer your question about how the polythene integrates with the walls, it is simply lapped down over the wall plate; trapped behind metal lathing; and rendered over.

Posted By: Peter Clark

It all depends on the plastic vapour retarder being installed perfectly, is this realistic? What about the joints between the plastic sheets? Will they be perfect? How long will the adhesive last?


No adhesive involved. Everything is physically lapped and trapped. Staple holes are insignificant, again because of above rafter ventilation]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64245#Comment_64245 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64245#Comment_64245 Fri, 16 Oct 2009 14:53:30 +0100 Mike George Posted By: davidfreeboroughMike

So how about:

12.5mm plasterboard;
0.3mm polyethylene VCL, laps & edges taped;
30mm PUR below rafters;
150mm Crown Rafter Roll 32 between 150mm rafters;
Tyvek Supro Plus sarking membrane, laps & edges taped;
38mm counter battens, 25mm vent to eaves, 5mm vent to ridge;
25mm tile battens.

This has a slightly better U value than the all PUR approach (0.16 versus 0.17) and is probably lower risk in terms of condensation. The ventilated batten cavity would be seen by some as belt and braces, but you could see it as insurance against moss filling the gaps around the tiles. Would this cost any more than you're currently paying?

David

Cost wise probably no more. And I understand why some would choose such a construction. The theory is that your construction is sound, but like I said, the experience I had seeing condensation on a breather membrane leads me to prefer the above insulation vented method. That's the main reason.

The condensation risk is a moot point I think and depends on factors other than just construction make up.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64247#Comment_64247 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64247#Comment_64247 Fri, 16 Oct 2009 15:31:31 +0100 fostertom Posted By: Mike GeorgeSo anything [peer reviewed or otherwise] which does not fit with your point of view on how vapour 'behaves' is wrong?If I'm right, they're very wrong - as usual my 'listeners' must be the judge of that. Do you feel that you're in my firing line Mike? If so, I wasn't particularly aware of that.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64248#Comment_64248 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64248#Comment_64248 Fri, 16 Oct 2009 15:49:05 +0100 Mike George Posted By: fostertomDo you feel that you're in my firing line Mike?

No, not at all. Just surprised that you can be so dismissive of peer reviewed stuff.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64264#Comment_64264 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64264#Comment_64264 Fri, 16 Oct 2009 18:10:01 +0100 fostertom Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64275#Comment_64275 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64275#Comment_64275 Fri, 16 Oct 2009 19:28:31 +0100 Mike George
Personally I trust what can be observed, measured or calculated by a combination of the two.

But in any topic, one person cannot 'know' everything. There comes a point where one must put their trust in others who are experts in their particular field. For me it is about who I trust more- A manufacturer who has a Cambridge University report supporting their position, or a manufacturer who does not.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64279#Comment_64279 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64279#Comment_64279 Fri, 16 Oct 2009 20:47:30 +0100 Tuna Posted By: fostertomWhat's all this faith in peers? Peers are by definition the ones who hold the conventional wisdom. Peers' fate is to be invoked when they agree with one, and to be ignored or rubbished when they don't. Majority (or even unanimous) agreement is not the same as the truth. There's no escape from the onerous duty to decide for oneself.

Nonsense. Peer review is about people with expertise in a subject looking for errors that laymen would be unlikely to spot, and checking that the article under review passes basic checks for quality of the analysis being undertaken. Peer review is not about following some consensus, it's about critical thinking - which some people seem all to happy to avoid if it doesn't fit their personal world view.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64280#Comment_64280 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64280#Comment_64280 Fri, 16 Oct 2009 20:49:44 +0100 bot de paille
One only has to look at scientific history to see that scientists spend the majority of their time being wrong whilst ridiculing anyone who steps too far outside the bounds of acceptable questioning.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64283#Comment_64283 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64283#Comment_64283 Fri, 16 Oct 2009 22:53:00 +0100 Mike George
Edit: Changed my mind, I think tuna has it about right.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64284#Comment_64284 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64284#Comment_64284 Fri, 16 Oct 2009 23:07:47 +0100 fostertom Actually, I admit the reality is prob not somewhere in between, but both extremes simultaneously.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64287#Comment_64287 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64287#Comment_64287 Sat, 17 Oct 2009 00:16:12 +0100 Mike George Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64304#Comment_64304 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64304#Comment_64304 Sat, 17 Oct 2009 11:08:59 +0100 fostertom Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64320#Comment_64320 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64320#Comment_64320 Sat, 17 Oct 2009 14:37:40 +0100 CWatters Posted By: Mike George This is my standard sloping ceiling scenario. From Inside to outside

Plaster, painted with matt emulsion
12.5mm standard plasterboad fixed with 45mm galvanised clouts at 400mm centers. All board edges fixed into timber noggins
Cheap polythene lapped accross at least 2 rafters and fixed with standard mild steel staples. Polythene lapped down walls to ensure continued air barrier at walls
30mm PUR insulation fixed with 65mm clouts to underside of rafters. Joints filled with expanding PUR foam
150mm x 50mm rafters at 400mm centers. Voids filled with 100mm PUR flush with rafter undersides and deliberately cut to leave 10mm short of rafters. The 10mm filled from above and below with expanding PUR foam.
Clear 50mm cavity between rafters above insulation
Breathable roofing membrane
Slates/Tiles on treated roofing batten
Eaves vented with continuous overfascia vents
Ridge vented with dry ridge ventilation system.

Some would argue that some parts of this construction make-up are unnecessary [such as a breather membrane]. But other than varying the insulation thickness to improve u-value, I believe it to be a belt and braces approach - Is it?


Sounds perfect to me.

The company that makes the breather membrane will say that ventilating the cavity under it is unnecessary but I doubt it makes much difference to the U-Value if the gaps are sealed as proposed.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64425#Comment_64425 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64425#Comment_64425 Mon, 19 Oct 2009 12:57:52 +0100 Peter Clark Posted By: Mike George
No, if the breather membrane is undamaged and correctly lapped, no water will get in.


Of course IF it is done correctly, that is one of the main points of breathability as I see it. IF it is NOT done correctly, now or later, what then?

Posted By: Mike George
Significant water getting in from above would show itself [somewhere] quickly. Smaller leaks would not affect the construction as the surface area of rafters exposed is such that a high level of ventilation would be adequate to ensure such water would evaporate and be vented away.

Any water vapour which migrates from the internal environment would also be vented in the same way.


This all applies to all types of construction, when done well, the point is, how easy is it to do one or the other well?



Posted By: Mike George
Peter Clark
If a hole is created in the plaster/vapour barrier, eg by picture hooks, water vapour could be getting in there, at a very low rate, but maybe continuously, day and night, for months on end, each year, year after year.

Mike George
This may happen, depending on internal conditions but is unimportant due to my ventilation comments above.

In general, the risk of humidity levels being high enough to cause significant risk of interstitial condensation are exaggerated in my opinion. Bedrooms for example do not continually ‘force’ water vapour into the fabric in a way suggested by some. It’s complete rubbish.


This assumes that water vapour having got through the paint, plaster and VB, also gets through the insulation, what if it does not and accumulates around the joists, might some condensation happen there? If so, it would be difficult for that water to get out again.


What is complete rubbish?

That bedrooms will have a higher relative humidity during the night if occupied?
Or that a higher humidity will constitute a ‘force’ encouraging water vapour into any holes in the walls?



Posted By: Mike GeorgeI don’t like timber framed walls personally, due to the risk of someone somewhere along the line getting it wrong.

So your answer to concerns about water damage in timber frame walls is, don’t build them?

Posted By: Mike GeorgeObviously there is nothing wrong with it when it is designed correctly and installed as such.

Obviously no one is arguing with that.

Posted By: Mike GeorgeUnfortunately, the complexity of the 5:1 design style makes problems more likely in my opinion

It is complex to discuss and understand perhaps, is it not easier to build?
How is this:
http://www.natural-building.co.uk/PDF/Pavatex/Pavaroof/Roof_PAVAROOF_PITCHED.pdf
More complex than what you have described?


Posted By: Mike GeorgeMasonry on the other hand, is easier for everyone to design and build at least in terms of basic weathering and hence durability.Correct installation of insulation however is another argument

Agreed, so masonry WITH insulation is not easier for everyone to design and build?

Posted By: Mike Georgewhich is why I use partial fill PUR

Why is this better than hygroscopic, breathable insulation?

Posted By: Mike GeorgeNo adhesive involved. Everything is physically lapped and trapped. Staple holes are insignificant, again because of above rafter ventilation

But to benefit from the above rafter ventilation, any moisture that gets through the holes in the VB has to also get through the insulation, both layers?

Sorry, this has got very complicated as a post.
You seem to me to be saying that the construction you described works well, as long as we exclude all the situations where it does not work well!
I am sure if you design a single roof pitch with no services, windows etc. and you supervise the construction, and any further work, then everything will be fine.
I am concerned, and this does appear to be the focus of the 'breathability' corner, about all the ifs:
What if YOU do not design it or supervise it?
what about timber frame walls?
what about complex roof shapes with windows and dormers.
What about when someone replaces a tile later and damages the roof membrane?
etc.

The construction is not 'robust' because it depends upon all those things being OK, but how likely is that in practise?]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64478#Comment_64478 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64478#Comment_64478 Tue, 20 Oct 2009 08:29:27 +0100 Mike George
What I will say is that there are many ways of swinging a cat . For me its about picking the best option for a given scenario. There is much more to consider than breathability and it should never be the number one consideration in my view. In my experience for most people the primary consideration is function [obviously linked to cost]

So we will have to agree to disagree please. I have my view and you have yours.

Just to declare my interest - I have never worked for a PUR manufacturer in any capacity. Neither have I ever sold or comercially promoted any product or particular building system. I have however spent quite a few years putting such constructions together on site. Never had a problem with my detailed roof construction yet. If you were correct in your criticisms I surely would have done by now.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64486#Comment_64486 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64486#Comment_64486 Tue, 20 Oct 2009 09:28:09 +0100 Peter Clark Posted By: Mike GeorgeWow Peter, that is a rather long list of queries. I'm not going to answer them sorry as I simply don't have the time. In any case I would only be repeating comments I have already made. I think we are going around in circles and it was obviously a mistake [on my part] to digress from the original focus of the thread by posting what I still believe to be my optimum [sloping]cold roof construction.

Sorry for the long post.

I don't think it was a mistake, thanks for the opportunity to talk. I respect your experience.

I am not sure myself that we have got to the bottom of this. I hope you are correct that there are no problems with your construction.

Certainly there are more ways to swing a cat...

Peter]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64497#Comment_64497 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64497#Comment_64497 Tue, 20 Oct 2009 10:28:33 +0100 Mike George Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64849#Comment_64849 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64849#Comment_64849 Sun, 25 Oct 2009 11:02:53 +0000 spoonandfork Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64851#Comment_64851 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64851#Comment_64851 Sun, 25 Oct 2009 12:09:38 +0000 Timber
It was saying that the gaps around the insulation (between it and timber studs etc) allows the passage of moisture vapour though the wall.

Funny thing though.... the BBA certificate also states that gaps around boards in installation will allow the passage of moisture vapour, however it also states in that same BBA certificate that all gaps around boards must be filled with an expanding foam!

I wouldn't trust anything that is spouted by the rigid insulation manufacturers regardless of what it is about. Othres are just as bad... did you know that another large insulation manufacturer don't have 3rd party certification for the use of their insulation in pitched roofs?!?! No-one has ever tested it! They stated that they/everyone had been using it for ages like that so they havn't bothered to test it.

Damage to VCLs in timber frame walls will cause issues, simple as that. I may have said in the past that it is not a huge issue, but some recent digging on my part says that anything over about the size of a single socket outlet can result in condensation on the external wall sheathing (if fitted). That is not to say that condensation results in a major faulure but it could if it were really bad.

To be honest, most of what people say and assume about breathability is just opinion and conjecture, and that includes what i say and think as well. Things like condensation risk calcs are all well and good but they are far too simplistic to really give a good and robust understanding, and that is even more undermined when the information from the product manufacturer's is sometimes completely wrong!

What really needs to be done is some indepth hygrothermal tests on different types of wall construction to show how moisture does really interact with the structure.

Timber]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64852#Comment_64852 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=64852#Comment_64852 Sun, 25 Oct 2009 13:11:48 +0000 ali.gill
The Canadian studies on timber frame homes that have been refurbished ten years later and black mould is found on the osb sheathing are great examples of identifying mistakes and designing new solutions.

Regarding peer review i think if peers review independently then there is a value in the technical knowledge and experience so long as it is experience based not reciting what they were taught or regurgitating someone elses work. A great example is Climate Change or the real history of King Arthur (both of them!) or 9/11.

When peer review is done in a group environment then you enter into the science of 'group speak' which is proven to alter an individuals original and independent perception and the brain even rewards with a dopamine hit when in agreement with the 'general consensus'.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65000#Comment_65000 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65000#Comment_65000 Tue, 27 Oct 2009 17:59:18 +0000 Mike George Posted By: TimberTo be honest, most of what people say and assume about breathability is just opinion and conjecture, and that includes what i say and think as well. Things like condensation risk calcs are all well and good but they are far too simplistic to really give a good and robust understanding, and that is even more undermined when the information from the product manufacturer's is sometimes completely wrong!

Timber

:clap:Well said that man]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65043#Comment_65043 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65043#Comment_65043 Wed, 28 Oct 2009 15:41:50 +0000 bot de paille
Toronto and Region Conservation (TRCA), with support from Works and Emergency
Services and Toronto Public Health, was recently awarded a $53,700 grant from
the Green Municipal Funds (GMF). TRCA will use the funds to install and test an
indoor air biofiltration system, also known as a breathing wall, at the TRCA
head office.


"We are very pleased to work in partnership with the City of Toronto, the
Federation of Canadian Municipalities and the private sector to test this
exciting new technology," said Dick O'Brien, TRCA Chair. "The Living City,
TRCA's vision, is about making the Greater Toronto Area one of the most
sustainable, livable regions in the world and this project is a step in that
direction."


"The breathing wall is an innovative alternative to improve air quality with
the potential to reduce energy costs and cut greenhouse gas emissions -
important goals of the Green Municipal Funds," said Mayor Yves Ducharme,
President of the Federation of Canadian Municipalities. "We look forward to the
results of this project and its potential to promote cleaner air."

Updates on the breathing wall project will be posted on TRCA's Web site at
www.trca.on.ca. For more information about the City of Toronto's environmental
initiatives, visit www.toronto.ca, or FCM's Knowledge Network at www.kn.fcm.ca.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65044#Comment_65044 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65044#Comment_65044 Wed, 28 Oct 2009 15:44:43 +0000 bot de paille
A cure for "sick building syndrome" may be in sight. Canadian researchers and business people are testing an environmentally friendly air-cleaning system nicknamed the "breathing wall."

Although it looks more like a modern art installation than an air-filtering system, the breathing wall is actually an indoor ecosystem composed of rocks, plants, fish, and microorganisms. In effect, it inhales dirty air and exhales clean air.

Modern buildings with closed-air ventilation systems have a nasty habit of circulating stale and polluted air throughout the office. Workers who breathe fumes, dust, fibers, and biological contaminants day after day could use some relief.]]> Article challenging the benefit of breathability https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65050#Comment_65050 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4579&Focus=65050#Comment_65050 Wed, 28 Oct 2009 16:46:37 +0000 fostertom