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.

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.

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.

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

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.

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.

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.

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.

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.

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

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.

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.

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

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

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.