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2 September 2008 at 10:03 am in reply to: avoiding cold bridging at junction between concrete slab and substrucure #35278
Steve has neatly summarised the 2 options. Turns out the slab is quite a span (10m) so looks like the thermalite support option is the way to go. The German book calls it a warm foot which is nice.
Same detail under any load bearing internal walls.
Nick
1 September 2008 at 12:22 pm in reply to: avoiding cold bridging at junction between concrete slab and substrucure #35277Hi John
Did I show you this book?
It has a few solutions.
Ideal is to use a detail that puts the insulation under the slab otherwise easy solution is insulate on top of it so that it overlaps the wall. Not ideal for moisture or thermal mass.
The Silver Standard Guidance on the CLP website (Volume 4) has a masonry detail (fig 5 that could be adapted).
My preference is the much discussed structural slab floating on insulation, come and have a look at ours next time you are down.
Nick
Mark
1. Suggest you have a look in PHPP and play with turning frost protection on and off. You will see what it estimates the electricity use to be I doubt it makes a huge difference in UK climate.
2. The person who told me is on holiday but I think some systems use the exhaust air to defrost by changing flow direction or something.
3. Unlikely to be a standby consumption as will either be controlled by the same circuit that does everything else or would/could be a simple stat.
Nick
Peter
Agree with David and Mark plus I wouldn't bother using fill between insulation and slab for extra thermal mass in the floor (David may correct me).
Nick
Hi Malcolm
The article is about active surfaces that use light to oxidise and so kill germs end presumably break down organic dirt. I can see the advantage for glass which gets exposed to high levels of solar radiation and which might be a large area and difficult to get to. Hard to see this being a benefit for loos, basins etc which get mucky very quickly and can't rely on gentle oxidation and rainfall to clean them.
The other aspect touched on in the article is a super smooth glaze finish and this is available although I am told is not without problems. Some manufacturers use a coating that can wear off whist others use special glaze technology with minimal porosity.
Something I should know more about but don't.
Re Aquatron however, this is not a compost toilet but a composting system fed by normal loos. For actual compost loos there is the possibility of shaping the pedestal or bench so that it is almost impossible to foul.
For sanitary ware cleaning in general it is possible to get away with very few chemicals, one of the most effective being water although there are concerns about its safety:
http://www.dhmo.org/facts.html
🙂
(Thanks for the link Judith)
Peter
Did you mean to say sub base on top of the insulation, surely under?
Obviously need some steel in the concrete and structural calcs from an engineer, standard stuff.
There are other discussions about this on the forum, I can remember posting a drawing of our foundations which are also our finished floor. Both ideas (slab found with insulation all round and polished concrete floor) were David Olivier's idea, from the days before forums!
Nick
Thanks Mark
I'm hoping Alan or David can provide definitive comment on the physics but if the numbers are right then this does seem a satisfactory explanation.
1. As anyone who has witnessed a blower door test will know, 50 Pa air pressure difference is a lot and certainly way above average. I think the average air infiltration is around 5-7% of that measured at 50Pa.
2. What is the desired rate of moisture diffusion relative to the desired level of airtightness? I'm guessing it is a lot less but that depends on the vapour control on the warm side.
Nick
Dave
expect you have found it by now but BRE PH forum is at:
http://www.passivhaus.org.uk/ click on forum and register.
You raise lots of wider issues that are, as you say, more philosophical or strategic and probably better discussed in another thread. Recurrent one is the 'how far is it sensible to go' at the individual household level.
Any other PHPP questions??
Nick
Dave
You will have to decide which forum is best for PH questions, do try the BRE one.
Nick
25 July 2008 at 6:52 am in reply to: Re: Re: are ground source heat pumps a good solution to heat an old stone church? #35458John
As the proposal is ground rather than borehole source, surely that would be a problem with such a high heat demand?
Ellen
I don't know about this product but just want to mention that 'Natural' does not guarantee benign and that 'chemical' is a very misleading word for manufacturers to use in the context of health or environmental claims.
For example some strong chemical solvents are quite harmless in the right dose, water for example whereas many people live in fear of a terrorists armed with castor bean extract for which there is no known antidote.
Even the strongest advocates of natural insulation will point out that there are more natural allergens than unnatural ones.
So it will help if you know what chemicals you are sensitive to.
Nick
Looks like nice stuff
anyone used it?
not sure about their insulation claim!
Nick
I don't have a problem with joint conferences as an extra but would like to keep the annual conference AECB focused.
Fine to market to RIBA members and get them to join and attend as per Tahir's post.
Why would they attend but not want to be members? Could understand if membership was £300.
Nick
I like the idea of Brighton if we can find a suitable venue.
Nick
Alan
How about some sort of membrane? EPDM? Contractor or DIY?
Otherwise interested to hear anyone's solutions for expansion/joints.
Nick
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