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1) What do you want to achieve?
2) How does he define “good”?
I hope the answer to 1 would agree with AECB Silver/Passivhaus standards. …If that's the case then the Project Manager's “good” solution is pretty much doomed to failure.
However, if you are aiming for something that satisfies the Building Regulations then you may have a chance (it all depends upon what the 'paint' is).
…What I can say is, without a great deal of research and investigation (including reviewing test results) I would not use or advise the use of this technique on any of my projects.
Hope this helps,
A polished finish as you describe it may offer some small improvements, but what I've read in research papers you'll get 99% of the way there simply using unfinished wet plaster.
If your only goal is to address condensation risk then, yes. 90mm PIR will do the job.
One additional thing to consider will be how the detailing prevents thermal bypass caused by any air gaps.3 July 2016 at 7:40 am in reply to: The use of a single room MVHR – are they any good? #39232
For units so small you'll be challenged to achieve Passivhaus (do the PHPP to verify), nonetheless you could create a good super insulated cabin.
The Lunos is an interesting option for small units. There are a growing number of suppliers. I've linked to one below:
Noise ratings are fine. Though there is a risk of wind blow through undermining actual performance.
Mark20 March 2016 at 11:49 pm in reply to: Advice: wet insulation at perimeter of insulated ground floor #39224
This interface is a challenge for many retrofits.
For one example of how this has been resolved see Andy Simmonds retrofit:
Foam could make the issue worse (traps moisture into timber as evaporation is prevented.)
Consider treating the timber in order to help improve resistance to moisture damage.
Achieving the supply/extract volume you require is indeed onerous. Strictly speaking 'purge' ventilation relates to the winter condition and removing moisture/smells. For the summer you should also be able to address overheating.
I would suggest that if you were trying to keep cool in the summer, but could not sleep due to fan noise, there would be a failing in the design.
In this respect, if the building is to satisfy the Passivhaus Standard, then all criteria (noise etc.) must be met. …arguably the need to minimise noise should be met in all cases no matter what standard.
Perhaps there is a common sense solution to the AD-F aspects of this question.
May be the question needs to be “why do the rooms need purge vent rates?”
…Cooling and/or fresh air?
Can cooling be provided by another means? If so why do you need a purge vent rate?
…Maybe due to moisture? As there is no bathroom (just bedroom and office) humidity/moisture loads are not onerous.
1) Use thermal bridging calcs to determine the surface temp at the junctions.
2) You can model two types of perimeter insulation – you copy/clone the worksheet.
You can use the thermal bridge inputs further down the worksheet.
I recall that Dr Feist suggested considering that you'd need about 200mm of foil insulation before it actually achieves the required performance (and even then you'd need to think about thermal bridging at compression points, dulling of foil reflectance, etc.)
…Basic idea: not a good idea.
I fail to see how these case studies address your initial query to Nick. Furthermore, Nick's comments recognised that the reported “slow down” of heat loss arising from the use of thermal mass is an inappropriate, and incorrect, proposition.
Passivhaus Basements for German speakers: http://passiv.de/en/05_service/03_literature/030307_basements.htm
No I don't know about the school. Sorry.
(In my view zero carbon buildings is a fools game. Once energy efficiency has been maximised focus upon the efficiency of other valuable things instead – like transport and food. This is likely to be much more cost effective and have greater success at reducing environmental impact.)
An interesting summary of conventional basement design for the UK may be found here
(Perhaps not the greatest resource for low energy detailing however.)
Jean-Marc. Show me (and others) the data for IFC basements; case studies backed up with moisture and thermal measurements would be ideal. Thanks.
Dave is correct. Speak to your certifer. The main thing with the windows is to avoid the risk of thermal discomfort from down draft and low radiant temperatures. For this reason the internal surfanpce temperature of the window should not fall below 16.4C on the design day (-10C). Whilst the 0.8 W/m2K is a good marker, and in the eyes of PHI applies to the UK, there are arguments for relaxation in the U-value if you are, broadly speaking, “south of Manchester”.
With regard to install: The position of the window within the wall (between int. and ext. surfaces) and the overlap of the insulation across the frame (where utilised) are key elements, as are the used of equivalent insulation types (cellulose, mineral wool, EPS, XPS etc). Again, firm this up with your certifier before this is set in stone.
Thanks to Nick Devlin for this link. (Some interesting scientific papers on basement design.)28 August 2013 at 8:33 pm in reply to: Window installation Psi value in accordance to the PHI #38947
What is being discussed is not “PHPP” it is a convention for calculating thermal bridges. This information may then be entered into PHPP. The main thing is that consistent and clear points of reference are used so as to avoid error.
Thanks for nitpicking though. Error now ammended.