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| Sidney Marsh: (05/05/05) | Insulation |
| Green insulation seems to be a bit expensive cvompared to the regular stuff we can get from B&Q. Why? Anyone would think we were going to spend the rest of our lives sleeping on it or something when you look at the price of sheep's wool. I thought there was glut of the stuff so to find another use for it like insulation should be just a bonus but it's five times the cost of glass fibre!
Is there anything else that we can consider? Thanks Sid | |
| (GBP) Keith: (05/05/05) | RE: Insulation |
| Hi Sid.
You are right sheep's wool is expensive but the price has fallen dramatically in the past few years. It's the usual story price being linked to demand. It was not until very recently that all sheeps wool insulation was imported from Australia or New Zealand. There is now at least one manufacturer in the UK with one due to start producing in Ireland anytime now so this might spark a bit of a price war. A cheaper option would be to think about Cellulose fibre insulation it is only about double the price of mineral wool (glass fibre as it is commonly known). there are quite a few companies selling it too. Do a web search for 'Warmcel' to find the best prices. Unlike sheep's wool however you would need to take into account that cellulose fibre needs a bit of up-front consideration as it mainly only available dry blown or wet sprayed. Keith | |
| Malcolm Yates: (09/05/05) | RE: Insulation |
| Hi. I know that extruded polystyrene is not strictly what you'd call green, but depending on where you want to use it, it is a fantastic material - especially for floors and walls. It's all cfc free now, so it's part there : and if it's left in place for a hundred years, it must be carbon positive and non-polluting ?
But it is a bit pricey though. I guess you pay for the pretty pink colour ! | |
| Arnold Wilkes: (19/11/05) | RE: Insulation |
| Hi there I have reciently found & ordered sheeps wool insulation that is slightly dearer than warmcel not that warmcell would do what I want under a suspended floor 1890's front room Terraced house.
I understand from my supplier that the Irish plant is not going ahead. Incidently I found them in The Green Building Bible. | |
| William: (21/11/05) | RE: Insulation |
| What would be wrong with Fibre Glass then?
Are its "green" credentials poor? I'm about to order a timber frame kit with 140mm of the stuff in the walls! | |
| Konrad Fischer: (27/11/05) | RE: Insulation |
| Some remarks ref. thermal insulation may be helpful.
What we found out by testing (Lichtenfelser Experiment) in Germany and by comparing additional insulated appartement houses with the same houses in direct neighbourhood without any improvement ref. insulation: There is no insulating effect compared with solid materials like wood and brick. Looking for Lichtenfelser Experiment you can find a figure of our test, where we had only 10 min IR radiation from a redlight bulb on different insulation materials each 4 cm (From above in opposite ranking: Fiberglass, Styrofoam, Foamglass, Brick, Wood fiber board, gypsum card board, solid pinewood). The temperatures are measured on the back of the boards, fiberglass had 40 degrees increasing, solid wood none! Besides the lightweight insulation has no capillar activity, what means this materials will never dry out the condensate what must go in, in spite of all vaporproofs, which will be moistured and mouldy after some years as our expierience shows. I do measure this with my equipement so often in my building consultations all around Germany. So I recommend not to crumble some lightwight insulation in your construction, instead take solid wood boards if youmust have a additional thermal insulation f.e. in attics. About 6-8 cm would be good. If you have a masonry wall, no additional insulation is necessary at all. In summer cool, in winter warm, thats the effect of solid material enveloping the rooms. Some explanations ref. radiation and conductivity: The problem is the way to measure the U-value. Not many in building branche knows how this is done. Warm air is ventilated to the proof material, cools off and is warmed again outside the 'proof box'. The amount of energy to rewarm is the base for the U-value. It tells only something about cooling of warm molecules on colder surface molecules of the test material. But: Does the cooling of your hand on a steel plate and a carpet in your room with both room temperature say anything about the wandering of IR radiation through the materials? Will sunlight - also an electromagnetical radiation - shine through an 1 cm board of styrofoam/polystyrene? And wood? So you can see what works best against IR radiation. And it is IR radiation, what is reasonable for about 99% of temperature losses through material, believe it or not. So lightweighters in the building construction are a really pest and only a fake and hoax of 'our' industries and their obscene slaves in science and administration! They damage buildings, invests and - most important - make persons ill with asthma, allergy etc. Thats the thing: No lightweighters as thermal insulation in and on the walls, in attics, under floors, in the foundations and so on. There is only one good purpose for those - as carpets, to keep the feet warm. Because the molecular contacts are fewer than the marbles on the floor can offer to the warm feet. And so there will be fewer thermal losses by direct molecular contacts. Inspite they have the same room temperature. You can prove that by measuring with an simple IR thermometer. Surprising? But true. And well known in earlier centuries from all building experts. Look on the good old buildings. Modern craftsmanship and engineering is the biggest danger for them, isn't it? Test details by Google search. | |
| John Pedersen: (27/11/05) | RE: Insulation |
| I'd like more information about this experiment, but can find only German documents. The google translation isn't very helpful. Does anyone know of any English translations of this report - if this report is correct, it would mean that the huge industry of producing the lightweight insulation materials is a fraud.... surely not... ! I know my lightweight feather jacket keeps me really warm. | |
| Keith Mitchell : (28/11/05) | RE: Insulation |
| Ah yes John your lightweight feather jacket keeps you warm but what do they wrap around athletes, exposure victims etc - shiny metal foil!
Like you I'd like to see a definitive report on whether we are all wasting our time with heaps of fluffy lightweight stuff filled with air or should we be all just staple expensive tin foil type stuff over everything? | |
| Keith Mitchell : (28/11/05) | RE: Insulation |
| Ah yes John your lightweight feather jacket keeps you warm but what do they wrap around athletes, exposure victims etc - shiny metal foil!
Like you I'd like to see a definitive report on whether we are all wasting our time with heaps of fluffy lightweight stuff filled with air or should we be all just staple expensive tin foil type stuff over everything? | |
| John Pedersen: (28/11/05) | RE: Insulation |
| A long time ago, I did my first attic conversion, and used polystyrene between the rafters as the only insulation. I spent a winter in that room, and it was horrible! On a cold winter's night, even with the heater going full blast, there was no way to keep warm. Even though the air in the room could be heated to 25 degrees - it STILL felt cold. I reckon the heat was radiating out through the roof very easily, and this is what made the room feel cold.
The next attic conversion was quite a bit better, but I still didn't go the conventional route. I used the polystyrene as before, but then used foil-backed plasterboard to line it. I spent many winters sleeping in that room and I was very comfortable, and I am sure that it was just the foil that made the difference. Now, I guess, to complete the logic, I need to do an attic conversion and use ONLY foil, and spend a winter in it. Building regs wouldn't allow it though... | |
| Arnold Wilkes: (29/11/05) | RE: Insulation |
| Thats what I have now and whilst its not as cold as outside its to cold to stay in for long, Its draufty especialy when windy as one might expect!
I want to insulate with Fibre glass & Sheeps wool but having read recient post's are not sure if I should try and place foil on outside. Or as I had intended to do place FB /SW behind foil. I will also put a netting material in to help retain insulation if roof is ever replaced. Arny | |
| Kim Williams: (30/11/05) | RE: Insulation |
| Konrad,
I am very interested in your comments. My understanding of conventional loft insulation materials is thatthey reduce heat lost by convection (many small air pockets) and conduction. If IR radiation is the main heat loss meachanism as you say then a lot could be gained by utilising IR relective materials on the inside of buildings. Any comments on this? I understand it is now possible to buy special paints which claim to have these kinds of properties. I would be interested to hear if anyone has experience of this type of product. Best regards. | |
| Paul Teather: (01/12/05) | RE: Insulation |
| The whole subject area is far more complex than building regulations would have us believe.
If the wrong insulation is used in the wrong way then there is a risk of condensation and subsequent structural damage. All suppliers should be able to prove that their method does not form such a risk. AS a general rule vapour resistance should be on the inside layer(s). It is definately not true that radiant heat is the most significant heat transfer in a loft (in winter). Although it is true that radiant heat transfer is more significant in floors and has a huge impact on our thermal comfort inside the house. Ventilation and convection (according to circumstances) tend to dominate. There is evidence of air movement through mineral wool and heat loss due to air movement above. Along with humidity issues this means that mineral wool is unlikley to perform as well as expected Adding a radiant barrier above existing insulation will lead to condensation risk. In my loft I have placed old carpets over the 4" of mineral wool. These are breathable,add to the insulation, and protect me from any risk of cancer inducing fibres. My future plan is to mark out the supporting timbers (for safety) and add a natural insulaltion above, as deep as possible. The loft is 'breathable', but would work for ventilated roofs (remember to leave air paths around the side). I do not plan on using sheeps wool as I refuse to support an industry that decimates hillsides that should be covered in carbon dioxide absorbing trees! (As most hillsides were, historicaly, apart from those above the 'tree line'). | |
| Liz Meddings: (04/12/05) | RE: Insulation |
| My understanding of the subject is that buildings lose heat via conduction AND raditation. Therefore, reducing the external surface temperature (i.e. bringing it as close as possible to the external temperature) reduces both these losses. Therefore any type of insulation will work to do this, whether it be a foil or loose fill newspaper. What determines how well the insulation performs is its R-value. (The sum of the reciprical of the R-value of each material in the construction deternies the U-value.)
Where lightweight constructions underperform is when the thermal mass of a building is relied upon to provide passive heating or cooling. Having conducted a simulation myself, and read reports, heavyweight buildings perform better by reducing the heat demand in winter (although only marginally) and reducing peak temperatures in summer. This effect is important in office buildings etc. with high internal and solar gains but not so much in houses in the UK's climate as gains are lower. Therefore, put whatever insulation you like in your roof (condensation matters aside, although that is what vapour barriers are for)! | |
| Paul Teather: (05/12/05) | RE: Insulation |
| Liz
There is a lot of confusion about lightweight vs. heavyweight buidlings. The actual physiscs of dynamic heat transfer is far beyond the simplified building regulations view of the world; Although there will be significant changes next year as all commercial (and large homes) will reguire simulations. But, simulations vary also and may produce significantly different results. This is due due to the wide range and variance of values that need to be input. One of the most significant variables is occupancy and heating patterns. For internmittently heated buildings (the vast majority) it is widely accepted that heavyweight buildings require 10-20% more energy (typicaly) in winter. In summer, a heavyweight building may be cooler during the day, but what about at night when a lot of the heat has been retained due to the extra insulation that may have been added? The reality is that most of the debate regarding thermal mass has not considered buildings with high insulation and air-tightness levels that do not have inherant diurnal(daily/nighttime) cooling characteristics (or have been renovated to loose these characteristics) Regarding Solar gain, even in the depths of winter a south facing window may receive 700W/m2 on a clear day (double this in summer). With such huge amounts of energy Shading of windows is a high priority; hence the inclusion of such measures in next years building regulations. | |
| Ranko: (11/05/06) | RE: Insulation |
| Well, this German report reminds me to urban legend that is spread here in Serbia - that Siporex is radioactive. I presume that this story was spread by brick manufacturers when the new material arrived, since I have never found any evidence for that.
The same way we can consider such reports about insulation and lightweight constructions. What I can say from my personal experience is that heavyweight constructions (such as my own house) must be insulated and that I have experienced both non-insulated and insulated period in the same house. From my experience, the house is much better when insulated. Every heat loss can be calculated with a good simulation, and you must consider your carpentry as a very weak point of a house - lots of energy is lost due to bad windows and doors. But if your carpentry is good, then you must provide some kind of heat exchange ventilation system, or you will have problems with condensation. This analogy can be used for houses, too: if you cover yourself with a cotton blanket, it wouldn't be enough in a cold winter night, but if you add some wool above, it would be much better. But if you remove the cotton blanket and use just the wool one, it wouldn't be good enough, since it pass too much air through. So, the house must have thermal mass to provide storage of IR and insulation to keep it inside the walls, as well as it must be airtight. | |
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