Green Building Forum - Fundamentals Tue, 19 Dec 2023 05:45:43 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 All our thermal problems solved with metamaterials http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10644 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10644 Wed, 08 May 2013 17:14:19 +0100 SteamyTea
http://www.sciencedaily.com/releases/2013/05/130508092924.htm]]> Natural Building Companion http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10630 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10630 Sat, 04 May 2013 19:13:55 +0100 djh
http://www.chelseagreen.com/bookstore/item/the_natural_building_companion:paperback%20+%20dvd

One of its strengths is that it is explicitly about building houses in the north-east of the United States. So they are open about their biases, and most of the biases are also applicable to the UK. You do have to allow for strange product names like Masonite (hardboard) and Homasote (not quite sure whether there is an equivalent?) and especially be aware that most of their examples use a timber frame. I confess that I'm viewing it with my own bias, and I am a balehead; a loadbearing balehead. You also need to watch out that you're not ripped off for the price!

I'm still reading, so I don't know how the story turns out.]]> A light hearted look at air tightness http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10600 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10600 Sun, 28 Apr 2013 12:05:15 +0100 Triassic Window size conundrum http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10548 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10548 Sun, 21 Apr 2013 09:51:06 +0100 Triassic Posted By: Ed DaviesOn my current drawings the windows are too small - I made some mistakes.
So what is the optimum size of a window, is there a formula?

If I want a large window, surely I just increase the heat input with larger solar panels.]]> Relative cost of building energy efficiency measures http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10316 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10316 Sat, 16 Mar 2013 10:41:00 +0000 Milk_No_Sugar
I'm curious to know from those who have build energy efficient buildings, whether passive-house or not, about the relative costs of the various principles that need to be applied to achieve an energy efficient building.

I have scoured this forum (which is great, btw), and I'm coming to suspect that air-tightness (or low air-permeability, to give it it's proper name) and minimising thermal bridging are the two most expensive measures.

If I can frame the question a bit first - let's assume that to get energy efficiency of space heating down to passivehouse levels (less than 15kWh/yr/m^2), it adds, say 20% to the cost of a new-build over and above building to UK 2010 part L regulations (as an aside - how does that figure sound? I've read that the average cost premium is 14%over standard practise, but it seems to me it's highly dependant on size and spec of the building in question, as well as it's location).

And let's focus on the 5 main elements which need to be applied - superinsulation (low fabric U-values), high spec windows (and careful design minimising North-facing and maximising South-facing windows), minimal thermal bridging, low air-permeability, and installing MVHR...

What would the breakdown of those elements be in terms of cost - 20% each (adding up to 100% of the cost premium over standard practise)? Or would perhaps thermal bridging and low air-permeability take up higher percentages, and perhaps superinsulation being the cheapest part of the process?

I understand some innovations have helped with air permeability (Viking House's silicone gaskets between T&G OSB being an excellent case in point), which makes this a difficult question to answer - I'm just trying to get a feel for the relevant costs. In particular, I'd like to know if, say the building had a more relaxed space-heating demand target of 25 - 30 kWh/yr/m^2, does it make sense to relax each of the elements equally, or is there a cost benefit to, say, keeping high spec windows and low fabric u-values, but relaxing a bit on thermal bridging and low air-permeability, or perhaps doing away with MVHR entirely (which the PH institute say is possible to do and still achieve 30kWh/yr/m^2 demand).

Your thoughts appreciated!]]> Build up of wall/roof etc to avoid interstitial condensation http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10138 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10138 Fri, 15 Feb 2013 19:35:30 +0000 RobinB
"When you put 50% or more of the insulation outside the air-tightness line then the roof structure becomes too warm for condensation to occur, it becomes like a warm-roof and it doesn't require ventilation."

I just wonder what most people think about this and if anyone can point to any science to back this up. It would be great as a rule of thumb that could be reliably applied to all building elements. Perhaps I'm asking too much?

I had heard that as long as increasingly higher U value elements were placed towards the outsdoors then there was no risk of interstitial condensation.

Googling about turned up this from down under.

http://www.abcb.gov.au/education-events-resources/publications/~/media/Files/Download%20Documents/Education%20and%20Training/Handbooks/2011_CondensationHandbook.ashx

thanks!

RobinB]]> hydrated lime - how much http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10059 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10059 Tue, 29 Jan 2013 13:22:30 +0000 djh
If you start from a 25 kg bag of hydrated lime, how much putty does that make?]]> Indoor air quality , CO2 levels http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9740 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9740 Tue, 23 Oct 2012 18:49:05 +0100 jamesingram http://www.kane.co.uk/online-catalogue/ambient-co-a-co2/kane-alert-co2
What levels ppm of CO2 should I be expecting in my home ?

As a side question ,any good links for a novice guide to CO2 and ventilation rates ?
found these so far
Ventilation and good indoor air quality in low energy homes
Finding proven good practice
http://www.goodhomes.org.uk/downloads/news/VIAQ%20final%20120220%20-%20PUBLICATION.pdf
MHRV how many air changes per hour?
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=4443
with Pauls link to http://oee.nrcan.gc.ca/Publications/infosource/Pub/hrv/contents.cfm?attr=4
Why Measure Carbon Dioxide Inside Buildings?
By Rich Prill, Washington State University Extension Energy Program 2000
http://www.energy.wsu.edu/Documents/CO2inbuildings.pdf
CO2
http://www.dhs.wisconsin.gov/eh/chemfs/fs/carbondioxide.htm

seems the North Amercians are more up on this than the UK/EU ?
or are they just 'burger eating worry monkeys']]> Straw Bale forum or maillist? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9934 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9934 Wed, 26 Dec 2012 12:08:29 +0000 jmansion Hydrophobic coating for limestone http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9879 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9879 Wed, 05 Dec 2012 12:51:51 +0000 djh
There's an overview at http://www.cardiff.ac.uk/news/articles/protecting-historic-buildings-9824.html

And the full paper is at http://www.nature.com/srep/2012/121129/srep00880/pdf/srep00880.pdf]]> Carbon Trading http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9834 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9834 Tue, 20 Nov 2012 21:40:00 +0000 SteamyTea http://www.newscientist.com/article/dn22516-full-steam-ahead-for-carbon-trading.html

I can see the advantage to industry in a cap and trade scheme, I just think it is a slower way of getting reductions.
Would a direct tax be faster and more effective?
Discuss]]> Roof Ventilation Gap Above Insulation http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9839 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9839 Wed, 21 Nov 2012 17:15:56 +0000 tony
Would 49mm be OK? or 25mm? or less?

The extra depth of insulation could save us a boat load of energy if it could be halved to 25mm.

I would be happy with a careful 20mm on my own house

Or was it someone at a desk in the 80's who did decide this?]]> Ash trees... http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9772 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9772 Sat, 03 Nov 2012 08:43:19 +0000 Joiner
http://ashtag.org/]]> Heat capacity of wood http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9782 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9782 Mon, 05 Nov 2012 13:12:15 +0000 Ed Davies
http://www.silverspray.co.uk/2011/07/25/wood-vs-other-construction-materials/

Chatting to one developer company, yes wood doesn’t have any thermal mass, but when you are heating (or cooling) the building, you don’t need to also heat (or cool) the physical ‘thermal mass’ structure either.
I think this is, at best, a half truth. The specific heat capacities (i.e., the amount of heat a given mass of material will store for a particular temperature change) for most building materials tends to be pretty similar, around 1 kJ/(kg·K) plus or minus 20% or so. About the only common materials which are well outside this range are water at 4.2 kJ/(kg·K) and phase change materials like wax, etc, over their phase change temperature range.

Of course, the density of wood is less than most other stuff used in building so the volumetric heat capacity is lower. On the other hand, you tend to need more of it.

Also, the thermal conductivity of wood is lower than other non-insulating materials so the volume available to temper the room temperature tends to be less too (see Fostertom's thread on the speed of heat).

Still, it's my view that appropriately designed wood can contribute to the thermal mass of a house. It's why I intend to use a post and beam structure with rafters exposed inside the house - to give a relatively large volume of wood as directly thermally connected to the house air volume as makes structural sense.]]> List of in house Winter Cooling Systems http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6652 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6652 Wed, 08 Dec 2010 23:13:42 +0000 tony
Cavity walls
Blob and dobbed walls
Ventilated underfloor voids letting draughts into your home
Cavity party walls
Extractor fans
Trickle vents
First floor voids will let draughts in from outside cooling both ceiling and floor above
Dormer bungalow first floor voids into lofts
Letterboxes
Sliding sash windows
Open flues
Redundant combustion air bricks
Soil and vent pipe casings
Ventilated chimneys
Thermal bypass in warm roof at gable & eaves roof-wall junctions
Dormer windows
Crittal windows
Cat flaps
Cold water cisterns - the loo one if not the CW tank - importing cold water which gets warmed up by the house
Drying clothes indoors - latent heat of evaporation is sucked out of the house interior
Drying logs indoors - ditto
Defrosting food from freezer indoors (do this in your fridge!)
Bringing anything cold into the house
Single glazed windows
Badly fitted floorboards]]> Long term fuel for the future http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9423 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9423 Mon, 06 Aug 2012 16:58:28 +0100 tony
My list

1) Solar

2) Electricity

3)Electricity from Nuclear

4) Solar PV

5) Electricity from Tidal, Hydro, Geothermal, small ammount of wind and wave]]> Temperatures for freezer http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9432 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9432 Wed, 08 Aug 2012 23:03:55 +0100 tony
This is a fundamentally important question, assuming I need a freezer, and the less cold I can set it the less energy it will use.

I suspect that there is a good element of belt and braces in the "recommended" temperature, how high could I go?

Energy savings could be huge here too with the first few degrees raised accounting for a bigger proportion of the savings.]]> Valuing Natural Capital http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9326 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9326 Thu, 12 Jul 2012 09:01:36 +0100 SteamyTea Membrane beyond dew point http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9303 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9303 Fri, 06 Jul 2012 20:10:46 +0100 Ed Davies
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=4490

on Sep 4th 2009

Posted By: biffvernonHappen I was talking to a structural engineer last night who deals with things like dew points in roofs. She looked at ours and thought it would probably be Ok because the dew point was likely to be well short of the impermeable membrane. There will be a temperature gradient across the 45cm thick layer of straw that forms the roof below the plastic. The position of the plastic will be well in the cold, sub-dew-point zone.

I really thought I was misunderstanding this until I read the last sentence. Nope I wasn't, but how can it be right; if the membrane is in the cold, sub-dew-point zone then surely horrible things will happen?]]> Measuring CO2 or Carbon http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9265 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9265 Fri, 29 Jun 2012 22:08:21 +0100 tony
Then the biggie do we count in CO2 from biological sources? or from wood and biomass, or digesters? etc. This is another biggie (as you all know I think it should all be counted in)

Without an agreed standard method of measuring carbon emissions how can we realistically even talk about reducing them?

This whole thing is a jolly can of worms.

Discuss!!!]]> Building sequestration http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9267 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9267 Sun, 01 Jul 2012 08:53:46 +0100 PeterStarck
Pete]]> Watts a lumen? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9203 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9203 Thu, 14 Jun 2012 09:38:54 +0100 marktime
Maths alert.

http://www.theoildrum.com/node/9217]]> Design Council Cabe... http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9164 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9164 Mon, 04 Jun 2012 12:45:19 +0100 Joiner
http://www.designcouncil.org.uk/our-work/CABE/

It's footnoted in the NPPF, para 62:

"62. Local planning authorities should have local design review arrangements in
place to provide assessment and support to ensure high standards of design.

They should also when appropriate refer major projects for a national design
review.In general, early engagement on design produces the greatest
benefits. In assessing applications, local planning authorities should have
regard to the recommendations from the design review panel."]]> Specific heat capacity of water http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8973 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8973 Fri, 20 Apr 2012 15:49:15 +0100 Ed Davies
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=7085&page=2#Item_2]]> UPVC windows http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8948 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8948 Sun, 15 Apr 2012 21:42:24 +0100 tony
Now we seem to talk about them in a very different way, have we all gone soft or moderate?]]> Reducing Domestic Energy Use http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8937 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8937 Sat, 14 Apr 2012 07:42:38 +0100 SteamyTea
I get the feeling that the aims of the scheme have been lost in the objectives of getting there.]]> Very interesting energy-use map http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8882 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8882 Mon, 02 Apr 2012 11:44:27 +0100 DamonHD
Very interesting to see pattern of red (high-usage) areas, and to drill down to your local area. Will be very helpful when doing energy audits, and could fine-tune boiler-sizing efforts, etc, in conjunction with local HDD data.

Rgds

Damon]]> District Heating Myths http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7841 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7841 Thu, 22 Sep 2011 12:43:29 +0100 tony
There are unfortunately the distribution losses to consider. These will always be high as insulating the pipes can only reduce the heat wasted not eliminate it. Then there are the high infrastructure costs to deal with not to mention the disruptive nature of the work needed to link existing homes together. This last aspect makes it a non starter for me.

To suggest that district heating of uninsulated homes could work out more energy efficient than the use of insulation .. well have lost out minds!!!]]> Green food ? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8705 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8705 Sun, 26 Feb 2012 15:14:07 +0000 joe90
Part of this drive is my wifes diagnosis of terminal cancer and the reading I have done over recent months has convinced me we are slowly killing ourselves with what we eat. I came across this article below and the film it contains, beware, it lasts over an hour but it contains some very potent messages including sustainability of food production. Its good to see that some Americans are seeing the light and trying to change.

http://articles.mercola.com/sites/articles/archive/2012/02/26/fresh-video-documentary.aspx?e_cid=20120226_SNL_Art_1]]> Swans neck bends http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8689 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8689 Fri, 24 Feb 2012 09:31:03 +0000 tony
135's would work a whole lot better and wouldnt block so easily or often

I have seen so many clugged up that others must have too -- is there any hope of a change.]]> How tall should a lamp post be? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8637 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8637 Thu, 16 Feb 2012 16:55:30 +0000 tony
The higher up they are the brighter they need to be and the more energy they use

The inverse square law applies to the levels of light suggesting the lower the better.

The cost of the posts and the number of standards tends to suggest that there should be fewer and taller.

I have seen shorter ones (under flight paths of planes) closer together working well.

anyone want to have a stab at the perfect height for today? I can believe that in the seventies tall was OK but is it still best?]]> Does it matter how much energy we use? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8524 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8524 Wed, 01 Feb 2012 07:11:29 +0000 tony
Assuming that a person can afford the costs can they use as much energy or fuel as they like?

In a responsible society should there be some control?]]> Warm and fuzzy on Geothermal http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8443 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8443 Wed, 18 Jan 2012 19:28:01 +0000 marktime
"The Earth started its existence as a red-hot rock, and has been cooling ever since. It’s still quite toasty in the core, and will remain so for billions of years, yet."

http://physics.ucsd.edu/do-the-math/2012/01/warm-and-fuzzy-on-geothermal/

Hat tip: The Oil Drum.]]> What is the hirarchy of renovation needs? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8105 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8105 Thu, 10 Nov 2011 17:19:23 +0000 Triassic
So a quick look around the building with the architect and we've come to the conclusion that we’ll need to demolish all but the front elevation. So this set me thinking on how best to spend our budget - if there were ten things you would do when rebuilding, (ranked in order of importance) what would they be and why?

Things I have in mind are --
Heating - type, why?
Under-floor heating to ground floor?
Air/Ground source heat? which one and why? Is it worth the effort?
Insulation, where and how thick?
Lighting - low voltage or standard?
Thermal store? How big
Double or triple glazing? Timber or plastic?
Wood burning stove or not? Back boiler?
Air tight?
Type of construction for replacement elements - timber frame or block or SIPs, then render ( to match the vernacular).
Solar hot water?
PV array?

Anything else you would do if it were you and why?]]> Killa wot ours? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5434 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5434 Tue, 02 Mar 2010 11:46:42 +0000 tony
most recently we see power usage expressed as kwh, KwH, KWH etc

It should be kWh --- small k for thousand (kilo) Watt for Watts and h for hours kWh always please

there are plenty of other things too you may notice that centimetres do not figure in my vocabulary -- these are not SI units metres or millimetres are though.]]> How does air leakage work? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8093 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8093 Tue, 08 Nov 2011 16:52:33 +0000 tony
I have heard it quoted several times that MHRV is not economic in air leaky houses.

Air leakage is a measure of how draughty a house will be.

However when it is calm (not windy) even the most appallingly leaky buildings wont leak much.

When it is windy they will leak big time.

This is a very good reason for having air tight buildings not leaky ones.

There is more to MHRV than economics. On a windless day all buildings need it, it is nice in all buildings but draughty buildings are losing so much heat and wasting so much energy that they should be made air tight. It is not that MHRV is uneconomic, inefficient, not needed or useful BUT that the building needs sorting out!

FUNDAMENTAL]]> The ten biggest inefficiencies in building http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7615 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7615 Sat, 23 Jul 2011 11:11:09 +0100 tony 2) joining up trades
3) collecting materials
4) waste
5) hold ups -- not "planning the flight or flying the plan"
6) Planning of works
7) poor communication
8) changes of plans or of mind
9) Architects
10) Structural Engineers]]> Interstitial condensation and MHRV http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7547 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7547 Thu, 30 Jun 2011 08:43:20 +0100 tony
This idea is a popular misconception and is untrue.

The amounts of moisture in the air inside a building in winter are very much greater than they are in the air outside, therefore when house is cooled as it escapes or percolates into the structure is can condense and start to try cause problems.

This is why in Canada they are very very careful when installing vapour barriers ditto in central Europe and Scandinavia.

In Britain as our homes become more air tight and better insulated we must not think that MHRV will save us from the necessity of mitigating interstitial problems.]]> Fill existing ground floor void http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7533 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7533 Mon, 27 Jun 2011 10:31:52 +0100 calvinmiddle
The recent discussions talking about fililng voids with polystyrene, got me thinking about our build and got a question that I'm hoping you can help me with. Our house is 1930's solid pebbled dashed construction with a suspended timber ground floor. I assume this as there are metal ventilation grill on a couple of the external walls below the floor level.

However, the kitchen floor is at the same level as the other floors but is terracotta tiled and a couple of these are loss and underneath is what looks like solid concrete, this floor is really cold in winter which makes me think it's solid. The hall way is exposed floorboards but at the junction between the kitchen and wall the concrete seems to continue under the floorboards. But one of the external vents would be under the hallway.

We are planning a substantial extension and internal remodelling of existing house, moving stairs and upstairs bathroom to get an addition bedroom, updating electrics and plumbing and installing underfloor heating.

So question is:

Extension will have solid floor, not sure if I go for something like Viking Houses passive slab or have no insulation but extend external insulation down a metre or so below ground level. If we want to have a solid floor in the existing house is it possible to remove existing floor, dig out a bit to install insulation (or again just extend external insulation down a metre) and fill with concrete/screed and have underfloor heating under tiles.]]> Environment Tools Directory http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7444 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7444 Thu, 02 Jun 2011 12:11:25 +0100 Triassic
Listing over 400 green environmental accounting software tools, and techniques for measuring environmental and sustainability performance, the Environment Tools Directory is the largest up-to-date and independent database of environmental software tools anywhere on the web.]]> In a reasonably airtight house does opening a window constitute ventilation? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7429 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7429 Fri, 27 May 2011 15:09:11 +0100 tony What to put Outside of underground insulation and other problems http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7270 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7270 Wed, 13 Apr 2011 22:37:24 +0100 Gotanewlife
Helping out my friend here in Italy. Lg underground garage/basement/plant room. 14x4m pool. GSHP, PV, Solar FPs, tank-in-tank, underfloor heating and this extends separately under the pool as heating it for paying guests. After much debate with ultra-safe Geometra, the pool will be a weak cement slab levelling base with concrete reinforced walls and floor built on top. The basement is also massive foundations and walls, all massively reinforced, but this is not a whinge about OPC and ancient anti-quake design.

Taking the house first: we have managed (with much arm-twisting) to get a DPC under the walls and columns (made of an under-tile flexible compound) and we plan to put 100mm XPS against the walls (but not extending below the foundations), tape it, spread some black liquid membraney stuff under bottom edge of the XPS over the DPC to seal them and then wrap in heavy gauge polythene also 'stuck to the black goo. Then wrap that in that stiff, thin, brittleish plastic with built in bobbles that protects the polythene and allows drainage. There is no insulation extending under the walls or columns but there will be 80mm XPS filling each room's floor, bringing the level up to the top of the foundations, polythene then sealed to the 'DPC', then 40 PIR/PUR over, butting up to the walls (ie 120 over the majority and 40 over each room's perimeter foundations. The will be a French Drain around the whole house at foundation level and each room is also drained to outside under the concrete floor in the European way. Clay soil backfill.

With the pool, there will be the weak cement 'slab', polythene, 100 XPS, reinforced concrete base then underfloor heating in a screed. The heavily reinforced walls will be built on the base (ie also on top of the 100 XPS and then 100 XPS around the walls butting up to the underbase XPS, so no cold bridges. The polythene will extend up to the top of the walls (in this case seamlessly due to the 8m wide roll!).

There are bound to be some comments on this! Ref the house, I assume there is no way to use bitumen over the XPS instead of polythene? Ref the pool, can XPS take the weight of the pool? V grateful for any other suggestions but please use generic product names as 1/ I don't know what they are and 2/they are probably not available here. Is it worth the extra effort of 2x50mm boards to offset joints?]]> Is there such a thing as foil-faced extruded polystyrene board? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7137 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7137 Fri, 18 Mar 2011 14:32:35 +0000 lineweight
The obvious choices for the insulation are foil-faced PIR, eg Celotex GA4000, foil-faced phenolic, eg Kingspan K12, or foil-faced PUR eg Kingspan TW55.

I was interested in looking at XPS as an alternative because it seems to be considered more eco-friendly than the above, doesn't seem to have the shrinkage worries, and is potentially cheaper (?). But I can't seem to find anyone selling a foil-faced version for walls.

Is that because such a thing doesn't exist?

The obvious question is, why do I want a foil-faced board - well my understanding is that it improves performance and provides a surface that can be tape-jointed for vapour and airtightness barrier - presumably if I went with simple XPS boards I'd have to do the vapour/air barrier with a separate sheet of polythene instead?]]> Vapour permeability of PUR/PIR http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6879 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6879 Thu, 27 Jan 2011 01:06:13 +0000 wookey
The 4 materials were foamglass, PIR, perlite and rockwool. Only the foamglass didn't transmit significant vapour.

Now this surprised me a little as I understood PUR/PIR to be 'fairly' vapour resistant. Is that in fact wrong? I'd certainly explect it to be _much_ better than rockwool, but maybe the nature of this test is such that you can't tell the difference between 'a bit' and 'lots' of condensation?

Clearly the foil covering is the bit that guarantees vapour-tightness (and keeps in the insulative blowing gas), but for example we recommend filling edges round boards with PUR foam to stop air circulation and vapour getting behind, but that only works if it's reasonably vapour-tight or the foam is covered with plastic/foil/tape.

Perhaps it depends on temp?

Aha. This paper: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc30890/nrcc30890.pdf (hooray for the intertubes - what did we do without them?) shows that the transmissivity rises rapidly with temp above 21C for both PUR and PIR. It's 1.12 and 1.03 (x10-7 g/m2.s.Pa) respectively, almost doubling to 2.09 and 1.62 at 32C and getting up to 2.66 at 50C (for PIR - PUR not measured). The increase seems to be linear, sugesting it'll be around 6-8 at 100C.

They also found that water absoption in samples stopped after between 40 and 64 days - equilibrium was reached then, although with about 40% water content on the warm side, but not penetrating more than 3cm into the material.

So the 100C test is not really indicative of performance in a real building.

Whilst looking for other relevant data I came across this BRE report on materials properties, which collects data from many labs round the world and synthesises them to give data on thermal conductivty, density, specific heat capacity, vapour resistance, and absorbtivity and emissivity.

It also has some fascinating discussion (if you are a building physics spod), e.g. noting that the vapour transmissivty of plywood becomes non-linear above 60% RH, being 20 times as much at 95% RH as at low RH.
http://www.google.co.uk/url?sa=t&source=web&cd=8&sqi=2&ved=0CEkQFjAH&url=http%3A%2F%2Fwww.esru.strath.ac.uk%2FDocuments%2F89%2Fthermop_rep.pdf&rct=j&q=materials%20vapour%20transmissivity&ei=Ir5ATbXRGIqKhQfIhsXNCA&usg=AFQjCNFxvR-vr0IvX7KLknIWZ3S-fRsSLQ&cad=rja

This report gives vapour resitivty in MNs/gm and I don't know how to convert that to the above x10-7 g/m2.s.Pa. (I guess I could work it out if I sat here long enough, but it's bedtime :-)]]> Recommended U-Values in the UK http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5654 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5654 Tue, 13 Apr 2010 00:15:11 +0100 mrben
I have recently bought an old leaky (and, to make matters worse, listed) 4-story victorian end-terrace and am scratching my head over how to evaluate its various amounts of leakiness in order to work out how to most effectively spend my limited cash (whilst not upsetting my listed building control "officer").

I think I am OK-ish with caluclating U-values of existing/ propsed materials, but I've had a pretty good look on a couple of occaisions but I can't seem to find a straight forward recommendation on the target (R- or) U-Values for specific aspects of insulation (roof/ floor/ walls/windows/ doors/ etc...) for specific UK regions (I'm in North Yorkshire).

This site in the US has a really useful step-by-step approach - and I think pretty much exactly what I'm after for roofs - http://www.oldhouseweb.com/how-to-advice/insulation-the-facts-part-3.shtml - but I think I'd need to know which HDD zone (1-5) I'd equate to here in the UK. Carbon Trust have a bit on Heating Degree Days here http://www.carbontrust.co.uk/cut-carbon-reduce-costs/calculate/energy-metering-monitoring/pages/weather-effects.aspx but the figures don't seem to tally (can't believe Yorkshire equates to Florida - I've never been there but I've seen Baywatch and it ain't like Ripon :bigsmile:) Do I need a Farenheigh vs Celcius conversion perhaps?

So any advice on that would be handy, please, plus any other recommendations on how to figure out (scientifically!) the most heat lossy aspects of the house first would be most appreciated.

Thanks & excellent forum BTW!

Ben

P.S. Anyone got any better prices on SapcethermF than this - seems high - but I am only buying 50 odd sheets...
2400x1200x10F/35mm Spacetherm @ £105.50m2 = £303.84 per sheet
2400x1200x10F/20mm Spacetherm @ £59.80m2 = £172.44 per sheet]]> Mould is Back - Feeling Rather Upset/Despondent http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6735 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6735 Thu, 23 Dec 2010 12:14:30 +0000 Gotanewlife
We heat 24/7 with radiators, maintaining about 21 in the living places and 18-19 in the bedrooms. The only rooms affected are the 2 big bedrooms in the corners with the small bedroom and the bathroom between them unaffected BUT we ventilate both these rooms without fail every day through open windows. The mould is better this year, much better, but I am very upset because I don’t know what to try next.

I have bought, but not yet fitted, an ultra-low Watt 24/7 extractor (no not HR), with auto-humidity boost etc but I intended to put it in the bathroom (at the moment we clean the shower room ceiling every week and I run a 100W bulb in the shower room ‘on a lot’). I had hoped by fitting it, it would deal with the shower room humidity issue and improve at least a little the overall air Q on the floor (on advice from other posts) but at £140 a pop I can’t afford to fit one in each bedroom (well not really).

In the last 2 days it has gone from zero/- deg to +10-15 degs but it 'looks like' the mould has been growing longer (though the stuff can grow so fast), and anyway with stable internal temps that shouldn't affect things should it?

What about leaving on the ceiling fan we have in one of the bedrooms (on low, 24/7). I suppose we will have to try opening the windows in these rooms as well. Feeling rather depressed about the whole thing. Any ideas?]]> Thermal mass explained http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6674 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6674 Mon, 13 Dec 2010 12:25:37 +0000 wookey
http://www.concretecentre.com/online_services/publication_library/publication_details.aspx?PublicationId=681

They also have a thermal mass calculator (a spreadsheet) which I haven't tried yet, but may also be useful.]]> Such a shame... http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6416 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6416 Fri, 15 Oct 2010 11:03:03 +0100 Joiner
http://www.greenbuildingpress.co.uk/forum_topic.php?thread_id=451

…because there were some interesting threads on there. From one…

http://www.ncwarn.org/wp-content/uploads/2010/07/NCW-SolarReport_final1.pdf

Which, despite being US oriented, give much food for thought, even for such a die-hard nukey as moi!]]> Criteria for Black Water Digester- must buy within one month http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6405 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6405 Tue, 12 Oct 2010 19:03:22 +0100 Gotanewlife
So far these 2 being considered:

http://www.evansthesewage.co.uk/UniGem6-70.pdf (a Marsh UniGem)

http://www.ecodigester.com/

But I am concerned over the ecodigester as very little detail given on site as to maintenance or power consumption. Could anyone actually recommend a digester or at least give some criteria on how to choose one. Do you get what you pay for - as clean enough is clean enough isn't it? Does it have to be powered in some way? Can these things be left 'off' for long periods when not in use ie no holiday makers? Many thanks.

EDIT - just found electrical usage of ecodigester - 234W - what's Eco about that? Marsh Unigem starts at 80W.

EDIT 2 - seems like http://www.bio-pure.com/online_shop_16.html 1-4 person tank, with 60W consumption and just one replaceable part (the compressor) and with longer emptying time might be best - any comment?]]> A deafening silence on GBF about this... http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6364 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6364 Fri, 01 Oct 2010 09:19:40 +0100 Joiner