Green Building Forum - Walls and walling - major feature - in 'Green Building' magazine

Walls and walling - major feature - in 'Green Building' magazine

GBP-Keith — Wed, 14 Mar 2007 19:21:48 +0000

We are going to dedicate a good portion of the summer edition to the discussion of walls in buildings. We hope to set timber and masonry proponents against each other in a head to head to see which type of walling might dominate home and commercial buildings in the future. We are also crystal ball gazing at what will be needed to meet the higher ratings in the Code for sustainable homes-probably concentrating on 4,5 and 6.

A major part of the feature will be given over to renovation and upgrading of existing buildings so if anyone wants to put their own personal experience in this area forward then please contact me.

We will also be looking into what the future holds for alternative walling systems - already well known eco methods such as cob and strawbale will be examined but also some of the more recent and not yet introduced eco walling systems, such as hemp clay and straw - particularly looking into how they may cope in the move towards low carbon buildings.

Other issues to discuss will be thermal mass; overheating; foundations; training and skills shortages; MMC; adaptability etc. etc.

If we have any walling anoraks in the community then come forward now. I may have a sub-edit job for you.

Walls and walling - major feature - in 'Green Building' magazine

fostertom — Wed, 14 Mar 2007 19:37:22 +0000

Very good, Keith.

Walls and walling - major feature - in 'Green Building' magazine

biffvernon — Wed, 14 Mar 2007 19:38:29 +0000

Posted By: (GBP) KeithIf we have any walling anoraks in the community then come forward now.

Dunno about anoraks but duvets may be the answer. You can buy polyester duvets at a lower price than some building insulation materials. Just got to work out how to convert Tog values to U values.

Walls and walling - major feature - in 'Green Building' magazine

GBP-Keith — Wed, 14 Mar 2007 19:48:11 +0000

How are your oak shaving in the cavity doing Biff? I bet the tannin is running through the mortar by now.

Joking aside, at Interbuild three years ago I saw an insulation batt made from wood shavings that Fillcrete were going to bring to market but I don't think they went ahead. Anyone spotted it?

Walls and walling - major feature - in 'Green Building' magazine

biffvernon — Wed, 14 Mar 2007 20:33:36 +0000

Oak shavings are fine, snug and dry behind various earth and lime plasters.

And joking aside, I wonder if the market conditions in the duvet trade, with keen competition between high-street stores and online dicounters, actually makes polyester fibre rather cheap when wrapped in a bed sized bag?

In the building trade folks are more likely to cough up whatever the cost, especially when, as often happens, they are spending someone else's money.

Walls and walling - major feature - in 'Green Building' magazine

GBP-Keith — Wed, 14 Mar 2007 20:55:10 +0000

Your point Biff. I guess is, "why don't people wrap up more rather than have over-warm houses?" They would probably be healthier too. the bugs just love our preferred 21-24 degrees. I think we covered that somewhat in the Autumn 2006 issue of BFF.

Walls and walling - major feature - in 'Green Building' magazine

biffvernon — Wed, 14 Mar 2007 22:21:16 +0000

No! The point is to embed the duvets in the wall instead of Kingspan or whatever

Walls and walling - major feature - in 'Green Building' magazine

GBP-Keith — Thu, 15 Mar 2007 17:25:24 +0000

Biff. Green practitioners have trouble convincing people to use sheep's wool, hemp or cellulose as insulation. I think our credibility will slide even further down the tubes if we propose old duvets. But do you know of a polyester insulation manufacturer? Polyester is used in the sheep's wool I think.

Walls and walling - major feature - in 'Green Building' magazine

Peter A — Thu, 15 Mar 2007 18:49:25 +0000

Keith,
Happy to help but will be bog standard developer stuff with a slight twist, not sure the bulk build market is ready for oak shavings. Used to be a trad boy but now sold on timber frame. Have you read NHER 20 their slant is that walls get to an optimum and then there is no point improving.

Walls and walling - major feature - in 'Green Building' magazine

GBP-Keith — Thu, 15 Mar 2007 20:07:07 +0000

The optimum is about a foot of insulation as I recall. does that tally with the NHER stuff Peter?

Where can I get a copy.

Walls and walling - major feature - in 'Green Building' magazine

Peter A — Thu, 15 Mar 2007 20:22:15 +0000

Keith, they didn't give too much in depth detail in wall construction, you can find it on NHER website. NHER 20 is their new flagship standard, it make zero carbon look like a walk in the park!!!
Have managed to get a wall down to .15 with a mix of kingspan and quilt o/a 250mm minus cavity and cladding, can email you calcs if you wish, I believe this is minimum passivhaus standard, which I am also told relates to approx code level 4.

Walls and walling - major feature - in 'Green Building' magazine

Chris Wardle — Thu, 15 Mar 2007 20:51:23 +0000

Keith, can you find someone who knows something about compressed earth blocks and get them to write a piece? These seem to be used to good effect in the States but I can never find anything about the subject in the UK. Always seems to be overlooked in favour of cob and rammed earth. Why is this???

Seems to me that CEB is a great way to build the structure of your house. It uses material from the site, so is low embodied energy, provides thermal mass, is cheap if you make them yourselves, gives a healthy internal environment and can be externally insulated with what ever you like.

Walls and walling - major feature - in 'Green Building' magazine

biffvernon — Thu, 15 Mar 2007 20:58:01 +0000

Posted By: (GBP) KeithBiff. Green practitioners have trouble convincing people to use sheep's wool, hemp or cellulose as insulation. I think our credibility will slide even further down the tubes if we propose old duvets. But do you know of a polyester insulation manufacturer? Polyester is used in the sheep's wool I think.

Yes. I wasn't suggesting OLD duvets, but pointing out that new duvets can be a cheaper form of insulation than some materials in the building industry. I think a TOG is a tenth of a R, so a TOG 10.5 duvet has a U-value just below 1.
Yes, Thermafleece is 10% polyester. Gives it better 'loft' I believe.

Walls and walling - major feature - in 'Green Building' magazine

fostertom — Thu, 15 Mar 2007 21:20:33 +0000

Posted By: Chris WardleCEB is a great way to build the structure of your house. It uses material from the site, so is low embodied energy, provides thermal mass, is cheap if you make them yourselves, gives a healthy internal environment and can be externally insulated with what ever you like.

Absolutely, Chris, something I want to develop. Get a semi-basement into the bargain! When and if multifoil insulation gets credibility, build single-skin CEB, insulate externally with multifoil, clad to choice, super-simple!

Walls and walling - major feature - in 'Green Building' magazine

ken davis — Fri, 16 Mar 2007 11:09:32 +0000

1. the duvet idea is not far off the mark. many old buildings had linings of sheepskins,sacking etc which led to decorative wall hangings of various sorts. since writing a thesis on energy conservation in historic buildings i have held the view that there is a potential market for providing bespoke insulated linings (sheepswool/duvets) which would just be used seasonally.there are various ways these could be fixed from velcro to curtain tracks or the sort of tensile rods used in tents etc. have approached several manufactures but its too specialist for the big firms. is there a small entrepreneur out there prepared to take the idea on or keith could do an article on it?
2. walls can not of course be considered in isolation. with good u-values and good air tightness heat recovery/air re-circulation is necessary so do we need as many opening windows (we will always need doors anyway), so why not have more fixed windows either in masonary or timber frame that have no frames. i have put glazing directly in to brick block walls on several projects with consequent reduction in installation and maintenance costs. cold let keith have some typical details if useful.
3. in consideration of pros and cons of various wall types it is worth taking in to account that the most sustainable place to build is in existing urban areas (which still have huge amounts of wasted land), close to adjacent buildings and on high cost land very thick walls (straw, earth etc) just are not feasible, masonary is best for fire, sound and thermal storage.

Walls and walling - major feature - in 'Green Building' magazine

fostertom — Fri, 16 Mar 2007 13:49:05 +0000

Posted By: ken davisglazing directly in to brick block walls

Fascinating - give us a clue?

Walls and walling - major feature - in 'Green Building' magazine

ken davis — Fri, 16 Mar 2007 17:26:39 +0000

you are welcome to phone me on 01424 752311 for quick description, but i can see that i am going to have to dig out the details now perhaps for inclusion in the next BFF....its much cheaper than buying windows though.

Walls and walling - major feature - in 'Green Building' magazine

GBP-Keith — Sun, 01 Apr 2007 18:33:21 +0100

Ken has sent me some pics and other stuff. (By the way Ken, it would be helpful if you could e-mail it to me as well) I'll try and find some space in next BFF Ken but no promises right at the moment. I've made insulated shutters before but we are sidetracking for the subject here. This thread is about walls, we can deal with windows in a separate thread.

Walls and walling - major feature - in 'Green Building' magazine

Paul_B — Sun, 01 Apr 2007 22:38:20 +0100

What about retrospective improvements? My house is only 9 years old and most internal walls are just metal frame and plasterboard. Should I remove the plasterboard and insulate, improve thermal mass and replace plasterboard with something else i.e. clayboard etc?

Paul

Walls and walling - major feature - in 'Green Building' magazine

Mike George — Mon, 02 Apr 2007 08:03:56 +0100

Hi Paul,

Thermally insulating internal walls walls in my opinion is a waste of money and resources, as you are only insulating one 'warm' room from another. Increasing thermal mass is a different consideration but in this application also not worth the effort [IMHO]

Walls and walling - major feature - in 'Green Building' magazine

Paul_B — Mon, 02 Apr 2007 12:34:21 +0100

Mike,

Thanks for your comments. Am I therefore right that in a relatively modern house, <10 years, there is simple nothing that is worth doing to improve the overall efficiency of heating / cooling with the internal wall voids?

What about room based heating controls. For example we rarely use the dining room during the week so should I set the heating at a lower temperature? If I have no insulation won't this cause a heat sink for the rooms next door?

What about draughts that may circulate in these voids? For example I have noticed recently (don't ask how ;o) that the WC on the ground-floor has two grap gaps in the wall where the sink has been fitted. This causes a howling gale of cold air when you put your hand next to it.

Walls and walling - major feature - in 'Green Building' magazine

Mike George — Mon, 02 Apr 2007 12:47:36 +0100

Hi again Paul,

It seems your sitiation is a little more complex. If you have a howling gale blowing in and around internal walls then something is definately wrong. Is it possible that these partitions are built on top of a floor with a ventilated void underneath? If this is the case then this should have been sealed against air infiltration and insultaed against heat loss at floor level.

Regarding room based heating controls these are a very good idea and yes, if you were to not heat these rooms then insulting the partitions would limit heat loss through themto the outside . I think that adressing the howling gale is the number one priority.though

Walls and walling - major feature - in 'Green Building' magazine

Paul_B — Mon, 02 Apr 2007 13:55:34 +0100

Thanks Mike. Downstairs WC is next on the list of projects and the sink is coming out with the loo so I can install a low flush toilet and plumb in ready for a rainharvesting feed.

Walls and walling - major feature - in 'Green Building' magazine

Mark Siddall — Mon, 02 Apr 2007 13:57:01 +0100

When discussing thermal mass please make sure both Admittance and Decrement Delay are discussed. I have had some interesting discussions with Excel Industries (Warmcell insulation) recently and once your start to super-insulating using cellulose fibre the performance gap between heavy mass and lightweight structures begins to close somewhat as the risk of overheating becomes less of an issue.

Mark

Walls and walling - major feature - in 'Green Building' magazine

Solar bore — Fri, 13 Apr 2007 10:35:37 +0100

Mark please explain this I have just read all this thread and can't understand where your piece comes in? Although it looks quite interesting.

"When discussing thermal mass please make sure both Admittance and Decrement Delay are discussed. I have had some interesting discussions with Excel Industries (Warmcell insulation) recently and once your start to super-insulating using cellulose fibre the performance gap between heavy mass and lightweight structures begins to close somewhat as the risk of overheating becomes less of an issue.

Mark

Walls and walling - major feature - in 'Green Building' magazine

Guest — Fri, 13 Apr 2007 19:35:50 +0100

From Paul T.
Mark has a good point - The concrete industry and BRE are promoting Thermal mass as the only way to avoid overheating. Yet when students at CAt (MSc) performed the same simulations they found that shading and ventilation control are far more important. In winter super insulated buildings (including ALL heat loss) tend to behave the same in winter as they stay warm, meaning that inertia of the thermal mass (high or low) is less significant (especialy as people in well insulated building turn the heating on and leave it on!)
So, there is a type convergence...

The good news is that it is entirely feasable to not worry about thermal mass (unless it has a purpose, eg as sun space)

Quick aside: In by Victorian home it got to 24oC on the south side and stayed under 15oC (peak)on the North side this week... On one side the thermal mass is storing energy, on the other side it is keeping the building cold...

Walls and walling - major feature - in 'Green Building' magazine

Mark Siddall — Tue, 17 Apr 2007 21:22:01 +0100

Solar bore,
My comments relate to Kieth's tag at the begining "We hope to set timber and masonry proponents against each other in a head to head to see which type of walling might dominate home and commercial buildings in the future." (I must say I skipped down the thread quite quickly....all the talk of duvets and stuff....perhaps I should have provided a quote so that you could tie my statement into context. Sorry about that.)

To pad out my earlier statement in a little more detail: I received some information through on the decrement delay of cellulose fibre insulation (in this case Warmcell 500). At a U-value of 0.13 w/m2K, you get a decrement delay of 7.3 hr. This delay helps to avoid day time over heating. A comparative calculation using mineral fibre insulation did not fair so well as it only achieved a 3.7hr decrement delay. The use of 60mm mineral fibre board (Pavatex Isolair) in compliment with the cellulose fibre insulation extends the calculated delay to 11.3hrs (note: U-value falls to 1.1 w/m2K). This confirms that the selection of insulation type does have an impact upon not only U-value but other aspects of building performance. Though I have no data to support it gut instinct tells me that foam insulations will fair no better than mineral fibre, if not worse. On this basis for any fair comparison between timber frame and masonry, when you are designing to CSH standards 4,5,6 or what ever, the whole range of timber varriants will have to be considered otherwise you don't get a fair or realistic picture.

Mark

Walls and walling - major feature - in 'Green Building' magazine

Mark Siddall — Tue, 17 Apr 2007 21:55:32 +0100

Correction Pavatex Isolair is wood fiber board not mineral fiber....oops

Mark

Walls and walling - major feature - in 'Green Building' magazine

GBP-Keith — Fri, 20 Apr 2007 18:01:52 +0100

I'm looking for quotes on how you think building walls/ design may have to change to provide for the low or zero carbon homes/buildings of the future. As it stands it looks like little will change other than the claims. Does anyone believe the demise of the cavity wall is afoot? Good quotes/interesting opinions will be published in next mag.

Walls and walling - major feature - in 'Green Building' magazine

Guest — Fri, 20 Apr 2007 21:48:12 +0100

Ah, with regard to the initial posting this is a different matter. The cavity wall (rather than masonry as a general concept) will face increasing challenges over the coming years. I know that research is going on, in the UK, to develop a masonry unit with a U-value of 0.1w/m2K. Though this is not a radically new technology on the European level for the UK this will ultimately provide a challenge to the status quo.
Technologically the cavity wall is flawed as workmanship can not be inspected as readily and as a consequence the actual performance (rather than theoretical) may be way for target. Greater discussion will need to take place before solid wall technologies begin to reemerge in the UK. Furthermore LA planners will need to become more enlightened (brick finishes will become a thing of the past) and accept the impact of environmental requirements i.e. the planners demand CSH 6 AND want it to look like a Victorian terrace....the two are not economically compatible and technologically desirable.