Green Building Forum - Fundamentals Tue, 19 Dec 2023 05:43:40 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Are dimmer switches just expensive on off switches? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13782 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13782 Thu, 05 Nov 2015 23:27:40 +0000 tony
Majority use is as on full or off in many cases this is the only way that they are used.]]> Are pvc cables rotted by polystyrene http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529 Fri, 17 Jul 2015 23:02:59 +0100 tony
This is a physical process, not a chemical reaction.

We need evidence that it causes a problem, to date there is none

Loads of pic cables have been laid touching polystyrene, I have seen some.

There clearly is not a real problem or we would have these all over the world.

As the plasticiser in the cable migrates into the eps, the eps shrinks back and in the vast majority of cases no longer remains in contact and deplastisation ceases.

It would require a lot of effort to deplasticise a pic cable enough to make it brittle, it would not happen in the real world

Any budding researchers reading this?]]> Masonry walls for thermal mass http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13381 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13381 Wed, 20 May 2015 14:01:07 +0100 Ed Davies
1) How thick?

In the other discussion:

Posted By: fostertom: “If the blockwork is for thermal mass, then Andy's 100 is all that's needed, and confers the max thermal mass that's possible - any greater thickness (like deemed-to-satisfy 190) adds no effective or active thermal mass, because on the diurnal-cycle basis of solar coming in thro windows daytime then leaving again at night, the temperature waves only have time to penetrate the inside 100 or so of blockwork before the heat flow reverses again.”

This makes sense in New Mexico where it's sunny almost every day and cold at night. Does it make sense in the UK where weather tends to cycle on a longer timescale than diurnally. I'd think that thicker walls would be better for carrying a bit of heat over dull chilly days (as long as they're suitably isolated from the ground, etc)?

2) External?

Putting the thermal mass up against the external insulation seems a bit nutty to me. Surely it'd be better to build the internal walls from heavy masonry and the external walls from insulated timber keeping them as thermally lightweight as practical. Sort of the reverse of many UK houses.

Obviously there are fire-protection considerations but for a detached house in a quiet area internal masonry would be more useful from a sound-deadening point of view.


[¹] http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13358]]> Map of attitudes to solutions to climate change http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13087 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13087 Mon, 09 Feb 2015 20:39:11 +0000 SteamyTea https://uk.isidewith.com/map/lzf/support-for-global-warming#z7]]> Relative humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13040 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13040 Thu, 29 Jan 2015 11:06:26 +0000 Ed Davies
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=13038

Posted By: cjard: “Warm air holds more moisture, so heat the air and the relative humidity will fall. As others note, cold spaces act like dehumidifiers. A surface below twelve degrees c will be liable to condensation, and single figures a virtual certainty if air that is "comfortable to live in" comes into contact ith it.”

While I sort of agree with the practical conclusions one might draw from thinking like this it seems to me to be a potentially very confusing approach and also from a pure physics point of view just wrong.

Air doesn't “hold” moisture. Water vapour is a gas like any other gas and coexists with the others in the normal way. Air no more holds moisture than nitrogen holds oxygen, argon, carbon dioxide, ozone, methane or any of the other components of the atmosphere.

The amount of water vapour (WV) present in a volume is largely independent of the other gases present. It only makes about 0.5% difference to the amount of WV if all the dry air is removed so that it's otherwise a vacuum.

What does control the WV partial pressure is the temperature, shape of the surface of any exposed water and anything dissolved in it. There's a good explanation of the basics in the middle of this page:

https://protonsforbreakfast.wordpress.com/2015/01/21/warmer-and-wetter-but-not-as-wet-as-i-thought/

I prefer the term “equilibrium vapour pressure” rather than “saturated vapour pressure” for this reason: it puts at the front the fact that the amount of WV is controlled by the balance of the processes of evaporation and condensation rather than encouraging an image of the air as a sponge which can only hold so much water in the holes.

Where the idea of the air holding water breaks down is when the surface of the liquid water isn't flat (e.g, when it's droplets condensed in a cloud with curvature one way or forming in the capillaries of wood or other materials with curvature the other way) or when it isn't pure (e.g., with salt particles forming cloud condensation nuclei dissolving in the droplets and becoming more dilute as the droplet grows).

More relevantly to the original thread, it also mattes that the air and surface temperatures may be different. When you think about it as the surface temperatures controlling the water vapour content of the air the second part of cjard's quote above follows naturally, rather than being a special case.]]> thermal mass/mass/decrement delay/thermal inertia http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13003 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13003 Sun, 18 Jan 2015 16:06:51 +0000 tony
U values determine heat losses so ignoring air leakages light, medium or heavy weight homes would loose the same amount of heat

ah but the heavier they are the more heat they can store and the slower they change temperature.

I like to be able to store a lot of heat for longer periods than days.

I also like the comfortableness of very slow temperature swings which also only fluctuate over periods longer than days.


Basics then:-

Thermal mass is good

Mass relates directly to thermal mass except where water is involved where it thermal mass is 4.2 times higher than its mass.

Decrement delay is a measure of how quickly or slowly a building responds to fluctuations in outside temperatures,

Thermal inertia would seem to be very similar to thermal mass but is a good thing to have lots of too.]]> Saving energy in the kitchen. http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12930 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12930 Fri, 26 Dec 2014 10:56:57 +0000 tony
• Only boil the amount of water that you require
• Use cool water washing powders and low temperature washes.
• Pre-wash rinse with cold water
• Cover pans when cooking
• Fill dishwasher and use short cycles when possible
• Hang washing on a clothes line rather than using a tumble drier
• Set fridge to 5C
• Set freezer to between -15 and -18C ensure seals are in good condition
• Use A or A+ rated appliances
• Switch off appliances at the wall when not in use
• Fit LED lighting
• Thaw frozen food in the refrigerator
• Don’t cook at a raging boil
• Consider doing it by hand rather than with a machine
• Defrost fridges and freezers when there is a build-up of frost
• Ensure good ventilation to the backs of fridges and freezers]]> Limiting thermal bridging and air leakage: Robust construction details http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13002 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13002 Sat, 17 Jan 2015 21:17:13 +0000 Mike George Some discussions particularly warm roof/cold roof thread prompted me to look this one up - Last time I looked this wasn't freely available but is now :)
It has its flaws as often there are conflicting requirements in different Approved Documents. However, these details concentrate on thermal requirements and are worth a look if trying to get your head around good principles of thermal design :bigsmile: http://regulations.completepicture.co.uk/pdf/Building%20Regulations/Construction%20Details/Limiting%20thermal%20bridging%20and%20air%20leakage-%20Robust%20construction%20details%20for%20dwell.pdf]]> Washing lines http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12964 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12964 Wed, 07 Jan 2015 00:44:25 +0000 tony
They dry clothes free! Indeed is there anything greener?]]> Check reveals http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12926 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12926 Tue, 23 Dec 2014 16:21:02 +0000 tony
We have been building checked reveals for ages, are we as an industry ready for change?]]> Can Smart Meters save energy http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12309 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12309 Tue, 08 Jul 2014 11:00:28 +0100 tony
HMG want to roll out smart meters and are hoping that they will save money (£26 pa by 2020)

In Holland they discovered that the energy savings were small and that these were as a result of behaviour change of the consumers, seeing what was going and wasting less.

Is this another lead balloon or should we support it?]]> Trada.. Timber Frame Construction (5th Edition) http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12319 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12319 Thu, 10 Jul 2014 23:01:43 +0100 Triassic Longevity of roofing materials http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12819 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12819 Sun, 23 Nov 2014 14:42:30 +0000 tony
Longer lasting would seem to be more sustainable

Lead seems the most durable historically, what modern materials last best.

Plastic seems inaprocriate to use eg for ventilation tiles and slates, rubber for universal flashing of pipes must be going to fail, mortar seems to fail before the rest of the roof.]]> EDF has to close nuclear 4 nuclear reactors http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12429 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12429 Mon, 11 Aug 2014 15:58:46 +0100 SteamyTea
http://www.ft.com/cms/s/0/4d5c670e-212f-11e4-b96e-00144feabdc0.html]]> Defining the ELH http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12387 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12387 Fri, 01 Aug 2014 02:43:30 +0100 tony
There are lots of definitions of energy efficient homes indeed all new houses are "energy efficient" and many claim to be sustainable and/or "eco".

I would like us to have a go at the definition in terms of energy use so how about this

Energy efficient = above 120kWh/m²/y

Low energy is below this and down to

ELH (extremely low energy) = below 50kWh/m²/y

PLH (phenomenally low energy) = below 15kWh/m²/y

(Edited in after FT. Autonomous homes zero from outside sources )


Anyone like to tinker with the numbers?]]> Undue water consumption. (Re GBM summer 2014) http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12231 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12231 Fri, 20 Jun 2014 17:00:09 +0100 tony
From now on all greenies will refuse to use the hot taps to wash their hands, I frequently do this already so I completely agree with cold water hand washing especially in schools, public places, etc

I am going to get this this discussed at the school where I a governor and at some of the local charities.

The cost savings in both water and energy across the country could run into billions!

Why have we waited so long to realise this, you are now number one green hero Cath brilliant article!]]> WBP ply http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12175 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12175 Thu, 05 Jun 2014 13:45:31 +0100 Ed Davies Long timber planks http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12174 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12174 Thu, 05 Jun 2014 13:43:07 +0100 Ed Davies
I imagine 4.2 or 5.4 metre lengths are dead easy - timber merchants will have it to hand. Up to about 7.2 m shouldn't be too difficult. But what about a bit longer - I need about 8.2 m or so lengths? I'm imaging it'd need pre-ordering and there'd be a bit of price premium per metre. Is that right or would it be unobtainium?]]> How to buy a gas boiler http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12160 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12160 Mon, 02 Jun 2014 21:35:10 +0100 Shevek
We also intend do as much of the fitting as possible ourselves.

Shall we just buy it online and then find a plumber/gas fitter to hook it up and commission it? Or should we find approved suppliers/engineers for the particular boiler we want and buy it off them?]]> Gutters, why? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12140 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12140 Thu, 29 May 2014 09:28:49 +0100 Triassic Screws vs nails http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12135 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12135 Wed, 28 May 2014 11:52:41 +0100 Ed Davies
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=12133&page=1#Comment_202682

Posted By: Paul in MontrealScrews are not approved for applications where there are shear forces, such as joist hangars. Only an approved fastener should be employed - usually a nail.
I can see why you wouldn't want a threaded part of a fastener to be used in shear but typical woodscrews have an unthreaded shank. If you make sure that goes right through the joint is there a problem? It seems to me that screws can easily have a larger cross section than nails so be a lot stronger. Also they can be extractable while being resistant to being pulled out.

What are coach screws made for?]]> Fundamentals - internal insulation of solid walls http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1055 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1055 Sat, 05 Jan 2008 00:16:04 +0000 Nick Parsons
There has been enough debate on this forum and elsewhere to suggest that the ideal is to retain thermal mass and insulate externally. I want to look at the vast number of situations where this simply is not feasible unless it's part of a whole-block approach. Take a Victorian inner-terraced house, for example. The neighbours don't want to insulate externally, to do yours alone would look daft, possibly be a trespass if you're a straight-onto-the-street terrace, and may have probs with cold bridging anyway.

I hope we can discuss the various up- and down-sides, with practical solutions and, almost as importantly, note where a non-green compromise may be required (in places where space is at a premium, for example)

Check list.

1. Space reduction
2. Cold-bridging (between ceilings and floors, at reveals, ?at party walls?
3. Other detailing
4. The importance of achieving the same U-value throughout
5. Air-tightness and breathing walls
6. Types and suitable insulation for such retrofitting
7. Can Green materials achieve low U-values without excessive loss of space?
8. Vapour control issues and mould growth
9. Substrate issues
10. Building Regs

1. Space reduction
This may be an issue when considering internal insulation and needs to be considered before going to far into the technical aspects. To some it may be the overriding decision to others negligible. Certainly the amount of space goiven over to the insulation can vary depending on the type of insulation used and what U-values you may wish to achieve but at a minimum 75mm off each external wall will need to be considered.

2. Cold bridging
Cold bridging will be inevitable but need not be of such a great concern as to scupper the idea. It can be minimised on walls with small returns onto internal walls (fig.1). The most difficult cold bridge area my considered to be the ceiling but if the wall thickness is being extended into the living space the some of the ceiling could be carefully removed and insulation inserted (fig.2)

3. Other detailing
Detailing will be dependent on the type of insulation used and the type of wall to which the insulation is being attached.

4. The importance of achieving the same U-value throughout
In theory any surface with a higher u value than any other is at risk of condensation, and thus mould growth. While typical u values differ for floors, walls and so on, to me the ideal for any house is to have all walls with the same u value, all bits of roof, ditto, etc. Otherwise you could be chasing a condensation problem around the house.

5. Air-tightness and breathing walls
Adding internal insulation may be an opportunity to improve the airtightness of the building. Before proceeding, a good deal of thought should be given to the opportunities for this.

6. Types and suitable insulation for such retrofitting
Most regular insulations could be employed as internal wall insulation but each will have their own particular installation requirements (quirks) . For instance, rigid insulation such as polystyrene can be self supporting so could be used without any supporting framework but obviously it will need fixing in some way so mechanical fixings or some sort of adhesive will need to be employed. Sheep's wool on the other hand will need a supporting framework but may appeal to those who wish to keep to natural insulation or breathing wall principles (see above)

7. Can Green materials achieve low U-values without excessive loss of space?
Yes they can but the user needs to understand that most natural insulations rely upon trapping air for their insulation value. if you plan to use a natural insulation you will need to have convinced yourself that the required space may be taken form the room. 4 inches (100mm) may suffice but six inches (150mm) or more would be best.

8. Vapour control issues
Including, has your chosen board even got a vapour barrier included. Some do, some don't. How good is your vapour barrier?-joints, the life of the 'sticky' on stick tape, etc. Vinyl-type paints often let you get away with a bad underlying VB, but breathable natural paints may not.

9. Substrate issues
Basically, are you trapping stuff behind which will rot? Timber studs (but arguably only if the VB is compromised), wallpaper, lintels. Keith suggested Gypsum plaster, but I have never had a prob with that, provided of course that you are, at the outset, satisfied with the stability of the substrate, partic when relying on adhesive only.

10.
Building Regs
You need this now. If you do work to more than 25% of a thermal element you need to comply. No policing, though. No-one would stop you if you dry-lined your whole hse with a woefully inadequate board which gave a u val of, say, 1.0, instead of the 0.35 required by Part L1B of Bldg Regs


Then close with supporting refs and credits to those inputting.

Nick]]> Thermal mass or No http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11624 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11624 Thu, 16 Jan 2014 20:18:23 +0000 SteamyTea
Does thermal mass in a building really help stabilise and raise the overall internal temperature or is it just an illusion?

I did my BSc Dissertation in a related area, mainly the effects of solar inputs on thermal mass. I wanted to show that you could heat a house with relatively low solar inputs (wintertime in Cornwall) by storing the energy in varying amounts of thermal mass. In the small model (physical) I created it matched the computer model I made. It basically showed that Newton's Law of Cooling holds true (probably why it is a Law and not a wish). I did manage to show that it was possible to store a small amount of excess energy for a short period of time (till the next solar cycle started), but it was a small amount in a highly insulated structure and needed fans to transfer the energy into the thermal mass. So not exactly a passive system.
In hindsight I think I proved nothing but learnt some interesting mathematical modelling and experiment design/testing.

Unfortunately real life is not like a laboratory and a house is not like an expanded polystyrene box with a window and a fan, the sun is obscured by cloud, temperatures vary, the wind blows and if you miss a rare event (a thunderstorm) you cannot go back and repeat the experiment.
But having said that I have over the years since thought about it a lot, and collected real life data. Disaggregating the variables is pretty tricky, but since a bit of prompting on another thread I looked at some of last winters data. I have limited it to variations in internal and ambient temperatures, windspeed and solar gain (the charts are below).
It is a bit hard to compare temperature with windspeed and solar gain as they units are different (though may be able to break the units down into SI ones i.e. J/m^2).

I have lots of ideas as to why it may not work, just as others have lots of reasons as to why it does. I am willing when time and cash permit to create 'Silly Sunday Experiments' to test ideas, but I may need online help in the design and execution.

So I hope that we can get to the bottom of this difficult and complicated problem.

Now some charts:]]> Definitions http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11937 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11937 Sat, 05 Apr 2014 20:33:41 +0100 tony
If you do then copy the list below and add what you think the definition is!

1. energy savings
2. energy use/consumption
3. energy efficiency
4. my preferred term is energy use reduction
5. using energy
6. wasting energy
7. carbon saving!
8. smart meter
9. smart energy monitoring
10. ...............]]> Plywood I-Beam: Not all things work http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11864 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11864 Fri, 14 Mar 2014 10:34:48 +0000 SteamyTea
I videoed it.
http://youtu.be/OuiuKs4S_BY

Not the greatest experiment, but this method has potential as I think it was the ply that delaminated before my adhesive did.
I have made a strait beam and shall see what I can do with that when it has fully cured.]]> Design for Future Climate: Case Studies http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11867 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11867 Sat, 15 Mar 2014 08:11:51 +0000 Triassic
The five adaptation case studies presented in TM55 were funded as part of a larger programme called ‘Design for Future Climate’ creating adaptation strategies for 50 UK building projects supported by the Technology Strategy Board. The aim of the programme was to build expertise within the UK design profession for delivering adaptation services and to build a body of evidence of the commercial advantages of considering future climate adaptation in current building projects, both new build and refurbishment.

This publication is presenting current practice and understanding, rather than commenting on the best way to carry out building adaptation strategies, or recommending changes to regulatory documents and procedures. The projects were undertaken on a commercial basis and so the extent of modelling, investigation and research were inevitably constrained by the overriding needs of the project, planning, programme and costs. In many cases it was the first time that the design teams had given serious attention to the concerns of future climate and so approaches may not necessarily be best practice. It must be noted that it is impossible to measure the weather in 40 years time today, and so the decisions and recommendations in these case studies were based solely on modelling using future weather scenarios without the ability to validate their models with real world measurement, which is not ideal.

These case studies on real building projects illustrate the lessons learned by design teams on improving adaptation resistance and resilience of building projects and show the impact that embedded adaptation strategies can have on the design decisions adopted by clients.

The case studies recommend use of the following adaptation measures: Thermal performance and dealing with overheating; water conservation and dealing with flooding risk; and material durability.]]> How much to insulate http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11558 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11558 Tue, 24 Dec 2013 03:13:08 +0000 tony
Currently good is defined by building regs under part L1b, which in my way of thinking insufficient but better than nothing.

There are some that are suggesting that less insulation than required by L1b may produce more savings, lower levels of insulation more widely applied leading to greater savings.

The problem I have with this is that it is very expensive to retrofit insulation and so we should do it well and to a good standard when it is done. The marginal cost of the extra insulation pales into insignificance compared to the cost of redoing it in all cases apart from DIY installs where there is already a greater willingness to do it well anyway.

As part L1b is seldom (understatement) applied or enforced, is it worth having it at all? Indeed should we encourage all insulation no matter how poorly done or when it is done minimally on the basis that it might be done more widely?]]> BP Energy Outlook 2035 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11619 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11619 Thu, 16 Jan 2014 06:24:41 +0000 SteamyTea http://www.bp.com/content/dam/bp/pdf/Energy-economics/Energy-Outlook/Energy_Outlook_2035_booklet.pdf
Probably worth a read.]]> WUFI and water http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11573 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11573 Tue, 31 Dec 2013 11:39:36 +0000 Ed Davies
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=11571&page=1#CommentBody_192463

Posted By: fostertomCob is ideal for safely absorbing/sequestering any water vapour peaks from cooking/showering, until able to re-dry - tho of course if surface temp is such that the vapour condenses, it won't get sequestered in that way.
Sorry, that's so surprising that more explanation is needed. I can't see why cob would store any more water *as vapour* than an equivalent volume of fresh air - rather it'll store less, surely? It would only be if the water condenses that more water could be stored, i.e., I'd have thought that only if the surface temperature was such that vapour condenses would such sequestration happen.

Posted By: fostertomEverything I've learned lately, from playing with WUFI, says that internal (or any) vapour barriers cause trouble, because they prevent drying-out inward. 95% of the water vapour in play originates from outside, ebbing and flowing thro walls; only a trivial %age from kitchen/showering etc.
Is that specific to masonry walls with no cladding or with render or does it also apply to walls with a properly ventilated rainscreen? In other words, is the external water which dominates come from direct rain impingement on the wall or from plain-old water vapour which is hanging around anyway.]]> CHP and Demand Matching http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11494 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11494 Thu, 05 Dec 2013 08:55:57 +0000 SteamyTea How important is draught-proofing? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11475 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11475 Fri, 29 Nov 2013 16:19:01 +0000 GarethC
"Full draught-proofing will save you on average £55 per year. Draught-free homes are comfortable at lower temperatures – so you’ll be able to turn down your thermostat. This could save you another £65 per year."

Might just be me, but that's not a great 'sell'. I think many might conclude 'if I spend a chunk of my time draught-proofing, I'll only get £5-£10 back per month". Even if the materials are cheap and you get your money back fairly quickly, I think the faff involved will turn many people off.

Basically I suppose my question is, is the EST under-selling draught proofing here? Not that I want to 'spin' things, but I think they should at least make the point that many homes could save much more than this (i.e. "...will save you on average £55 per year, but up to £X for many leaky homes" or something). Anyone agree?]]> Are double height rooms sensible http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11400 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11400 Wed, 13 Nov 2013 22:49:46 +0000 tony
Too much heat rises increasing temperatures and heat losses and energy use.]]> Is it financially beneficial to invest in triple glazing?) http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11228 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11228 Sat, 05 Oct 2013 14:20:19 +0100 Triassic
The energetic performance of glass types (does triple glazing reduce required heating energy?)
The environmental impact (are the extra energy and material for fabrication less than its savings?)
Cost (is it financially beneficial to invest in triple glazing?)

http://www.except.nl/en/#.en.articles.194-energy-and-cost-analysis-double-and-trip]]> Cradle to Cradle: "Be good, not less bad" the closed loop economy http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6409 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6409 Wed, 13 Oct 2010 17:08:33 +0100 jamesingram from wiki,
Cradle to Cradle "Simply, it is a holistic economic, industrial and social framework that seeks to create systems that are not just efficient but essentially waste free. The model in its broadest sense is not limited to industrial design and manufacturing; it can be applied to many different aspects of human civilization such as urban environments, buildings, economics and social systems."

there's a conference on the idea in Bradford , 29th of November to 1st of December 2010

http://www.ellenmacarthurfoundation.org/education/business-and-education-summit-the-bradford-101-conference

"The conference, aimed at high level business and education stakeholders, will be an opportunity to hear some of the world’s leading closed loop economy thinkers (see below). Ten guest lectures around one key perspective on the transition to a sustainable economy. The focus will be on skills, jobs and entrepreneurial opportunities in a ‘cradle to cradle’ or ‘closed materials loop economy’.
This lecture series will be introduced by Professor Michael Braungart, one of the world’s leading designers and industrial consultants. It will discuss the implications for business, community and education of moving from a linear, ‘take-make-dump’ economy to a circular economy where economic systems thinking and design is based on ecological principles. Waste is designed out of the equation and the economy features closed materials loops increasingly powered by renewable energy. Considerations of place, scale, resource and diversity will be at the core of development."


Michael Braungart one of the authors of Cradle to cradle
"Holisticially good products "
http://www.youtube.com/watch?v=MPgjHqp9tTM&feature=related

"Wear a tie to save the energy produced by 21 EU powerstations"
http://www.youtube.com/watch?v=B1ga4lZNjrc&feature=related

William McDonough: The wisdom of designing Cradle to Cradle and "Eco cities"
http://www.youtube.com/watch?v=IoRjz8iTVoo&feature=related

Interesting stuff

http://en.wikipedia.org/wiki/Cradle_to_Cradle_Design
http://en.wikipedia.org/wiki/Cradle_to_Cradle:_Remaking_the_Way_We_Make_Things]]> DG vs TG windows southwest aspect http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11338 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11338 Sat, 02 Nov 2013 11:47:48 +0000 chan what wold be optimum for heating season with SouthWest unobstructed aspect 3g or 2g?

As it stands we have kitchen dining and bedroom SW facing with single glassing and towards eve (12 till sunset) get massive amounts of Light/heat so worry that 3G might reduce this evening heat and loose beautiful afternoon and evening light compared to DG. We are in Northwest Ireland by coast.

Münster joinery Dg 24mm u1.3
VS
TG 36mm u1.1

I have actually ordered 3g but wonder should we change south west window to DG.
Thanks]]> When it is not worthwhile http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11299 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11299 Wed, 23 Oct 2013 22:00:30 +0100 tony
Following Dr Jones' line involving teeth, I would suggest that at the point of sale the seller should bear the cost of upgrading.

Exactly how this would work in the rented sector where huge problems exist I don't know. I cannot see this sector ever reducing its energy use. The bottom line has to be that landlords should foot the bill possibly in return for increased rent as the energy bills for the tenant will then be lower.]]> LESS IS MORE: Energy Security after Oil (LIM) from the AECB. http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11227 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11227 Sat, 05 Oct 2013 13:19:24 +0100 jamesingram http://www.aecb.net/featured/have-you-seen/
down load PDF here
http://www.aecb.net/publications/less-is-more-energy-security-after-oil/

"This report has been published at the end of an unprecedented 15 years in UK energy policy history.It began with the formal acceptance of the need for a climate change policy by the last Conservative Government in 1997 and culminated with the Climate Change Act and the 4th Carbon Budget. LIM is a significant new contribution to the debate.

“LIM offers an alternative to the emerging orthodoxy of large-scale electrification of heat and road transport as a way to achieve or beat the UK’s 2050 CO2 emissions target. This is based on more vigorous and systematic pursuit of energy efficiency throughout the economy; on technologies such as large-scale solar heat, piped to urban buildings; a road and air transport system synthesising liquid fuels in part from renewable electricity, supplementing the biofuel resource; a small electricity supply system, supplied largely by despatchable sources, assisting with network security; and the more vigorous pursuit of carbon dioxide (CO2) sequestration options, particularly in the biosphere."]]> Is Insulation really necessary? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10779 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10779 Wed, 12 Jun 2013 14:15:34 +0100 Wul I'm planning on a shepherd's hut style design. The walls will be timber and the roof corrugated steel. Exterior cladding will be 20mm larch, running vertically with battens to close the gap between boards.
I'm looking into insulation but wondering if it's really necessary. Insulation works by trapping air, right? Could I not just trap the air between my inner and outer wall skins and do away with insulation? I appreciate that no timber void built this way will be airtight, indeed I'd encourage a degree of airflow for ventilation and condensation dispersal.
For me the down sides of insulation are:
1) It costs money
2) It is a good place to trap condensation/water (a timber biulding in Scotland will absorb moisture)
3) It's a nice cosy home for mice

This 7ft x 12ft hut will be heated by a 3Kw woodburning stove, so when its cold there will be heat on tap. On a hot day, it may be beneficial to have a slowly moving current of air into the bottom of the walls and out the top.
I realise that insulation will protect from overheating in summer, but my experience with lightweight timber biuldings (or even upstairs in any attic-trussed house) is that eventually the heat soaks through and it's just very hot until the sun goes down.
It makes me wonder if I'd be smarter just to use the 50mm air gap between my timber walls as my "insulation". The same may apply to my tin-exterior, timber-interior roof?
Any one got a view on this?]]> What shape and which direction should a building point http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11210 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11210 Wed, 02 Oct 2013 19:23:10 +0100 tony
and which direction should it point in order to achieve the same goal]]> Visual intrusion of Windturbines http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10053 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10053 Mon, 28 Jan 2013 14:22:20 +0000 SteamyTea Should they be 'sized' by installed capacity, blade swept area or diameter, total height, hub height, annual generation or something else.

My idea is to use one over the BMI formula but change the mass to rotor diameter.

1 / ((Pi.d^2) / 4) / Hub Height^2)

So that will be :
one over Swept area divided by hub height squared

So a turbine that has a 60 m diameter with a hub height of 100m would have a visual impact of 3.5

Same turbine 20m higher would have a visual impact of 5.1

A 4m diameter with a hub height of 10m would have one of 7.9

Same turbine 5m higher would be 17.9

I think that this would take into account smaller turbines generally begin nearer buildings and larger turbines generally being further away (though not exclusively).

Thoughts anyone?]]> Would you prefer low energy, low carbon or low cost? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11168 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11168 Sun, 22 Sep 2013 20:29:12 +0100 tony Does a hut need a vapour barrier and vented cladding? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11099 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11099 Tue, 03 Sep 2013 10:18:06 +0100 Wulbert Some folks do not bother with an internal vapour barrier and I can't help thinking that they probably won't have any problems because a hut is not occupied for long periods like a house (gets a chance to dry out) and is generally much more "open" than a house. Door, window left open to the fresh air. Does it make sense to create a big, air-tight, polythene bag and then open the door every few minutes or sit with an open window (which due to small scale could be 15% of the total wall area) enjoying the bird-song. Surely I can do away with the vapour barrier in a 7ft x 12ft hut?
I've looked at this build:
http://www.greenwoodleathercrafts.co.uk/styled-23/index.html
And the chap has no vapour barrier internally and no exterior load-bearing skin other than the cladding rain-skin. Also no air gap between his breather membrane and cladding. However I can't help thinking that he will have no condensation problems at all and his hut will give decades of service.
My opinions are only gut-feelings from my experiences as an amateur self-builder. Any one got a more educated but open-mined view of the need for air-gaps/vapour barriers etc, in a garden hut?]]> What's the standard for roof joist centres? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11080 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11080 Wed, 28 Aug 2013 17:47:10 +0100 Wulbert 'm building a ply/50mm celotex/ply sandwich floor for my shepherd's hut project. I've got my 1200 x 2440mm ply and I assumed that I could run my 75 x 50mm floor joists at 600mm centres.
However it seems that the ready cut Celotex comes in 450mm widths. This is the stuff made for pitched roofs.
The nice drawing I've just made will need to be re-done. It's annoying me because I thought I knew this, and it means that my insulation width will not tie up neatly with my ply width (1.2m). I really, really don't want to be cutting celotex with a handsaw.

I'd always assumed that roof joists/trusses were 50mm thick, at 600mm centres (2ft in old money). However, that can't be right, if Celotex are selling between-joist insulation at 450mm wide.

Either roof trusses are 6" thick or the centre spacing is less that 600mm. So, what is the standard thickness of a roof joist/truss and what centres are they placed at?]]> A thin, flexible, finished sheeting material needed http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11024 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11024 Fri, 16 Aug 2013 15:49:23 +0100 Wulbert This is for an internal ceiling in a garden hut.
Being lazy, (or always seeking elegant solutions; depending on who's side you are on) I'd like to use a sheet that would give me an almost finished ceiling surface which just needs a coat of paint or sealant.
Problem is I can't seem to find a suitable, green material. I was in a caravan on holiday last week and the stuff on the ceiling looked ideal; curved and fixed with panel pins with a pre-finished surface. Hooray no extra work/cost!
However, since it was an 80's 'van, I'm guessing it was made of nasty stuff and not at all green.
The nearest material I can find that has the physical properties I want is "good old" hardboard but I'm not sure of it's green credentials. (or its fire resistance in a small hut)
I called Timbmet and they suggested flexible MDF, but I know it's not green.
Does anyone know of a suitable material?
( If not I'll probably end up with tongue and groove and hours of sanding, knot filling, etc..)]]> Carbon intensity of gas http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10485 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10485 Wed, 10 Apr 2013 01:11:37 +0100 Seret 2e of gas is 0.1836kg kWh-1, and I've seen this used regularly on this forum to compare the merits of gas vs electricity. However, the published figure for grid intensity (0.5246kg kWh-1) includes factors such as distribution losses, while the figure for gas only includes the actual carbon released at the point of combustion. Digging a bit deeper into the DECC figures it looks like once you add indirect sources of emissions in the gas distribution network the actual figure for natural gas is 0.20155kg kWh-1.

So what, you ask? Well for a start it means that a mains-powered heat pump would only have to achieve a CoP of less than 2.4 to result in lower emissions than a 90% efficient gas boiler.

To my mind if we want to assess the actual impact of our consumption we really should be factoring in everything that it takes to get the fuel to us for every fuel, not just some of them.]]> Free U value calculator http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10974 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10974 Tue, 06 Aug 2013 20:34:13 +0100 jamesingram http://www.thermalcalconline.com/u-value-calculator/u-value-calculator.html]]> Justification of petrochemical based insulants http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10905 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10905 Thu, 18 Jul 2013 08:07:01 +0100 tony
In my book it is. It is a much better use of fossil resources than burning them!]]> Sheet sizes http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10882 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10882 Wed, 10 Jul 2013 23:11:15 +0100 tony
How crazy is that and how much unnecessary waste results from this?

It is even a waste of my time having to trim plywood to fit 600mm centres]]> The Mechanical Transmission of Power http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10793 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10793 Mon, 17 Jun 2013 21:45:22 +0100 jamesingram
"The Mechanical Transmission of Power (3): Endless Rope Drives
You don't need electricity to send or receive power quickly. In the second half of the nineteenth century, we commonly used fast-moving ropes. These wire rope transmissions were more efficient than electricity for distances up to 5 kilometres. Even today, a nineteenth-century rope drive would be more efficient than electricity over relatively short distances. If we used modern materials for making ropes and pulleys, we could further improve this forgotten method. "

Well , there's a thing ! Any thoughts how this might be used in todays world ?]]> Silver nanoparticle Water Filter http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10657 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10657 Fri, 10 May 2013 14:26:59 +0100 SteamyTea
http://www.newscientist.com/article/mg21829165.400-silver-nanoparticles-provide-clean-water-for-2-a-year.html]]>