Does Roof or Wall Insulation Do Any Good?

[TRUSTME]

I have got it into my head that if houses were turned upside down like BOATS, and filled with water - the water would come cascading out so fast that and you cannot fill the building with water no matter how long or how hard you tried ? Lets imagine it was HEAT you are pouring into it, then I hope you can see what I am getting at, insulation is porous, insulation is laid in short and long strips and laid in patch-work-quilt rolls. And heat pours out of building non- stop. For instance on holiday last week in Keswick I saw a house with 10-chimneys, ten x 8-inches round big blooming disused chimneys and dreaded thinking about his heating bills?

EXAMPLES SEEN ON MY TRAVELS. Seen often by me inside unfelted house roofs (tiled roofs) meaning houses with no roofing felt placed under the roof tiles) with roof tile gaps so large between each tile -you can easily look down into the street below and see what is going on. Also you can hear conversations being held and watch small birds diving and crawling under the roof tiles to find, build or enter their nests. Eaves Soffit gaps are numerous, sometimes as many a 60 large 16" xs 8" soffit gaps are located in the roof eaves, you can look down them and see daylight, feel the wind on your face, or look into the garden? You then have another 501 other gaps which start at ground level and finish at the chimney tops all allowing water, vapour or heat to escape. And if heat gets blocked, like water it diverts into another escape hole and away. So, it needs to be asked does glass wool or fibreglass do any real good, or is it a bogus claim?

 

[stem]

Odd analogy. Water and heat are different things completely so have different requirements for containing them.

It's not just the insulation per se, that keeps the heat in (or out), porous insulation contains air and it is the trapped air between the fibers that acts as an insulator and prevents the heat loss. A string vest works on the same principle.

If you have central heating, when it's running see how long you can keep your hand on the exposed flow pipe from your boiler, probably a few seconds at the most. Cover it with pipe insulation and you could keep your hand on it all day, because the heat isn't being conducted through the insulation.

Regarding the roof insulation examples you have seen, it may be a 'cold roof' ie one where the roof space isn't heated, so it doesn't need to be insulated. The insulation sits on the ceilings of the rooms below which are heated, thus preventing heat travelling from them and up into the roof space.

As a youngster I lived in a semi without insulation and solid fuel heating, the bedrooms were cold and when it snowed (it used to snow every winter in the 1970's) it melted on our roof, made obvious as the house we were attached to would have a thick covering. One year dad fitted insulation in the loft, the heat input remained the same (no thermostats) but bedrooms were now warm and toasty and the snow settled on the roof.

A few gaps aren't that major. In the winter you may go out for a walk wearing warm clothes and a coat, but your head isn't covered. Are you still warm, yes. Would you be if you took all your clothes off [I don't suggest you try this] no, so insulation works, even with a gap or too.

 

[TRUSTME]

Reply to Stem; I am a insulation engineer of some 50 years standing. I say string vests do not trap air, its impossible, a myth. I read somewhere that in some nation like China they fall about laughing at the idea that a string-vest can save and trap heat, Westerners have tried it -but soon realised their mistake.

WATER leaving a boiler is hot, and gets cooler very quickly, its soon gets absorbed by its man-made surroundings and cold-air, why not boil a kettle - pour the water into a pan and within 10-seconds its luke warm, turn the gas on and time how long it takes to boil it again.

In the UK 1800 - 1955, the cold roof was to save house-builders erection costs. And roofing felt was not around, made or installed then. What a mistake that was. Snow on roofs - it sounds good but is another myth, the sun melts snow, not escaping heat, I have photos like you describe and one needs to take into account wind-flow, the suns orbit and time of day and a houses position in a street. I fell for the roof-top snow argument myself, but discovered that it was totally untrue - an Urban Myth story. And here is the clincher: The answer my friends in blowing in the Wind, the answer is blowing in the wind, the wind-factor is what matters, people can withstand the cold but not cold winter winds. Scott Expedition to disaster and death exposed this argument, keeping out of the wind saves lives. Odd but so very true.

 

[IT Minion]

Fibreglass works exactly like a blanket. Your duvet at home is not air tight, air, water or heat can and does move through it. Although top tip, don't **** your bed.

The point of all insulation is to slow the movement of heat. You can make a big difference with rockwool etc but you hit diminishing returns after about 200mm and the importance of drafts becomes a much bigger issue.

The other point is that if you have gaps the heat still needs to get there from wherever it is. If you have a perfectly insulated building and at one end a single window wide open it'll still hold a decent proportion of the heat.

The Scott expedition was a great demonstration of what happens when you run out of supplies, not really for home improvement

 

[TRUSTME]

@ It Minion: You make a lot of decent valid points thank you, but how do we get the message out to the public, and they ACT on it. For instance my close friend and neighbour lived in his small back-kitchen with a 2-bar electric fire and an overcoat and trilby hat always on his head. Why was his house always so cold - because he had no front door letter box, the letter box had somehow come off or had been removed and he never fitted a new one. The hole in the door was about 12 inches x 6 inches, always open, and he refused to allow me to fix it for him, I even bought him a new letter box but never saw it again. He died, he expected to die one day, and it never ever occurred to him his letter box shortened his life by maybe 7-years. Cigarettes shorten lives for between 20 - 40 years but do smokers care - do they heck. Would you like to sell insulations benefits to a smoker?

Returning to topic: I once had a huge truck with 1100 size bus tyres, one day I noticed a nail in one of them and pulled it out, I wish I had'nt, this huge tyre deflated in seconds. How many tyre inner tubes can you fit inside an average house, maybe 1200 if you stack them properly and they all contain air, and how do you stop it reaching the outside like my truck tyre did. You can't. I know one way of doing it- but it would never get off the ground. Its used in the USA houses, but the UK population are not heat saving fanatics. And as for fibreglass mat, I have laid or sold over a million rolls and do not think anyone of them did any good. Can heat be saved? No, it cannot. You buy a £1-00 worth of heat for 20 pence worth of benefit. Scot's men died from wind exposure, biting cold winds, are you aware in the Artic if you fall in the sea and are not pulled out within 13 minutes you die. Walking about in that cold wasteland must be horrendous, even seeing it on TV gives me pneumonia.

 

[Harry Bloomfield]

How many tyre inner tubes can you fit inside an average house, maybe 1200 if you stack them properly and they all contain air, and how do you stop it reaching the outside like my truck tyre did. You can't. I know one way of doing it- but it would never get off the ground.

The big difference of course is that air in a tyre is considerable pressure, make a hole and it will quickly try to equalise the pressure. There is not much if any pressure difference between the inside of a house and the outside, so heat and air will not flow through any small holes easily, the big problem is heat lost through walls and rooves/ ceilings. The best way to keep it in, being insulation - the thicker and better, the more energy is saved. A house is difficult to make air-tight and would not be healthy if it were, there priority there is appropriate ventilation.

I have made my home as draught proof as possible, but ensured it is adequately ventilated as, when and where needed. I have also CWI, DG and double insulated my roof. My heating bills for the type/size of my property are quite low, despite the heating being on throughout the day.

 

[TRUSTME]

@ Mr H Bloomfield: I take on board all you have said, thank you. My views are: 90% of all UK homes contain such massive heat saving structural faults, faults that are so extensive that they cannot be corrected they should be demolished. I realise this is an impractical suggestion but never-the-less it is true.

What few people realise is coal and coal fires had strong advantages over gas, it was cheap, and threw out lots of heat which warmed the main living room in a grand fashion, gas which replaced it become a RIP OFF INDUSTRY - the price of gas and heating homes is far too high. When coal was around Victorian homes were liveable, with gas prices being what they are these homes are now a costly burden on society. The answer is to use HOUSE WRAP when they are being built, a secondary answer is too board roofs with 3/4 plywood first, then to lay breathable membrane on top of the plywood boards, then to tile the roof. Sealing the tile joints with a silicone might be a step forward as well. Do read up on Dupont USA House Wrap, and go on You Tube to see what house builders now perform in the USA.

 

[Harry Bloomfield]

What few people realise is coal and coal fires had strong advantages over gas, it was cheap, and threw out lots of heat which warmed the main living room in a grand fashion, gas which replaced it become a RIP OFF INDUSTRY - the price of gas and heating homes is far too high.

I'm not sure any of that is true, I was brought up in the coal era. We only ever had the one fire lit, in the living room and that only warm close to the fire due to the cold draughts. It never had a proper hot water supply. The fire required a lot of upkeep and constant attendance, you got up on a morning and it had to be relit then a lengthy delay before it produced any worthwhile heat. I don't know what the coal cost, I never bought any, but I understand it is now cheaper to heat with gas. It never had a proper hot water supply.

From one room which was warm sometimes, I now occupy a much larger house than I grew up in, which has central heating. Every room in the place is comfortably warm, no drafts and I can easily afford what it costs me, because it is efficient - despite being a mid 20th century build, originally built to be coal heated, but two decades down the line was converted to town gas heating.

I'm not sure your point about the US is valid either, the US has lots of poor quality, badly insulated housing stock too. The UK has its own versions of high efficiency homes too.

 

[TRUSTME]

Harry B. With respects: The average gas bill is now around £1400 per year, 3 weeks actual earnings, over 50% of the population do not switch the C.H on as they cannot afford it, others switch it on for 1 hour in the morning, 2 hrs evening, yet they still get hit with huge bills (gas, water, telephones and petrol bills, are 4- gigantic rip-off industries with British Gas leading the way). Gas from the ground is a waste product, and its true cost is minimal, almost FREE in Gulf regions. Additional proof of sorts is how many people now have wood burning fires, ask them what they think of central heating and gas.

I know you must have heard of Passive Heat Houses, I stayed in one last week - it was awful, the first two days the sun shone warm and bright and it was great, then the dark clouds and non-stop rain came and this house became a Frigidaire home, my wife and I both returned with the flu, right now I have scabs on my nose tips and top lips - from cold sores caused by wiping my nose 5-dozen times per day. Our daughter had booked it for us for 7-days, after 4 days we dreaded staying there, and did not want her to know why. We left on Day -5 claiming an hospital appt called us away. New houses in the USA are far superior to ours, old houses everywhere are redundant and need the bulldozer. A grotty terrace house in London costs £500 000, are you tempted to buy one?

Housewrap and roof-wrap are winners, fibreglass and rock wool are questionable products, did you know if they contain just 00.06% water or moisture they fail,and any thickness over 50 mm is entering the land of diminishing returns. If 2 inches doesn't do much good, then how the hell does FLUFFING it up to 10" work. I spent 7- years watching it being made, and should know.

 

[Harry Bloomfield]

Harry B. With respects: The average gas bill is now around £1400 per year, 3 weeks actual earnings, over 50% of the population do not switch the C.H on as they cannot afford it, others switch it on for 1 hour in the morning, 2 hrs evening, yet they still get hit with huge bills (gas, water, telephones and petrol bills, are 4- gigantic rip-off industries with British Gas leading the way). Gas from the ground is a waste product, and its true cost is minimal, almost FREE in Gulf regions. Additional proof of sorts is how many people now have wood burning fires, ask them what they think of central heating and gas.

I do think you are making some of these figures up, or have an axe to grind.

My gas bill, for heating and HW for my three bed semi was £507.32, with the place heated almost round the clock, when ever heat is needed. Gas from the ground, is no more a waste product than is oil from the oil wells, they prospect for it and recover it at terrific expense. It all has to be paid for, including it's transport. Most of your petrol bill goes to the Exchequer not the producers. Telephones, once a luxury for many are dirt cheap, rather than huge. Has the cost has reduced over the years, the facilities a phone line offers has gone through the roof. In real terms the £22.38 I pay each month for my fibre + line, is just a fraction of what was paid in the 1960's. Until this month I was paying an extra £8 pm for anytime free calls (again just a fraction of what calls cost), instead I am paying just £7 pm for mobile unlimited calls, texts and a data package.

People of bought wood burning stoves as a way to get free heat, if they have free access to wood to burn. I have lots of free wood I could burn from my garden, but I burn it in the garden or offer it for free collection for those with such stoves. I see lots of wood burning stoves installed, many are just installed for the novelty and their owners soon get bored with the task of filling and cleaning them.

No I am not tempted to buy any terraced house, nor any house in London, or anywhere else so built up. I am very happy where I am thank you. I think everyone must know about the law of diminishing returns on all insulation, it follows the inverse square law - double the thickness, you only get 1/4 extra benefit and that law begins at a fraction of an inch thick.

You cannot catch a cold or flu from being in a cool environment. I take issue with your suggestion to bulldoze older houses, most are very capable of being brought up to modern standards. I you like the US and its homes so much, then go live there, I'm happy with the UK.

Do you happen to have some financial involvement in this house wrap and roof wrap system perhaps?

 

[Notch7]

Gosh, some confused thinking in this thread!

I wouldnt know where to begin.......

 

[IT Minion]

...any thickness over 50 mm is entering the land of diminishing returns. If 2 inches doesn't do much good, then how the hell does FLUFFING it up to 10" work. I spent 7- years watching it being made, and should know.

Any insulation beyond an arbitrary minimum thickness is diminishing returns. That's physics.

As to the fluffing it up, the more it is fluffed the better. It isn't the rockwool that is insulating, it's the air. Air is a really good insulator, it just has an annoying habit of moving, taking heat with it. The idea is to keep small amounts of air in small enough spaces to prevent convection and with a minimum of other materials. That's how PIR, rockwool, aerogel, spray foam and virtually any other household insulation works. Otherwise you'd just clad buildings in 50mm of solid rubber sheets.

If you don't get why a fluffed bit of rockwool is better then with respect you might want to start again from the beginning.