Insulating an old house - Breathability!

As always in this site, you will hear me banging on about breathability in old buildings.

Insulation needs to be breathable.  It also needs to discourage condensation.  Modern insulation is the work of the devil in this regard.  We constantly battle modern insulation. It comes in all forms – but you will be familiar with the foam insulation panels with silver foil on both sides – we see them all the time in houses with damp problems. Water streams down the back of the insulation as condensation – it's almost endemic now. We get damp roofs and ceilings, wet walls that have it as internal or external wall insulation.. And then there's cavity wall insulation – blown fibreglass is a major issue – every time we see it, the cavity is sopping wet, and the house full of mould. We have videos and photos of the stuff coming out of our ears. There's blown cellulose fibre too – the same thing happens. And guess what – CIGA – (the Cavity Wall Insulation Guarantee Authority) can't be bothered to help unless you threaten them with nuclear war – why? Well – guess what – they are owned and run by insulation companies or their executives. The whole system is a joke – and is milking hundreds of millions of pounds out of a Government that doesnt understand, or doesnt want to know.

Is Fibreglass Insulation Safe?

I originally had a few words about how I just don't like fibreglass on this page.  

A few innocuous words about how nasty it was.  I don't like it - every time I get near it I spend days coughing and retching.  I've spent weeks having hospital tests and treatment after exposure to fibreglass in loft spaces. So I need our readers to understand the dangers of the stuff, and take precautions..

Then I got a bullying letter from a manufacturing association of billion pound international companies who make fibreglass. They didn't like what I'd said.  What! Me... on this innocuous little website – making a few personal observations about how horrible fibreglass is – how it causes me serious health problems every time I come into contact with it – but then they ARE billion pound corporations and ugly, corporate bullies who care only about billion pound profits, and nothing about the little person in the street. I guess I should be honoured that they take so much interest in this little website – perhaps we are a bit close to the soft underbelly without realising it?  

Hmmm.. now this immediately flags up all sorts of warning bells for me - what the hell have they got to cover up? Why would massive corporations want to bother with a tiny little website about old houses?  Their letter made me feel sick to the core – how DARE these arrogant corporations try to stop me telling the world that their products cause me serious medical problems? The arrogance – the sheer bullying – the Nazi style arrogance – it left me angry and speechless..

That got me thinking.... Remember the cigarette companies?  Remember Asbestos companies?  The big chemical companies - Bhopal comes to mind – wasn't it Dow – who make fibreglass and the resins that release formaldehyde? ... So I started to do a bit of research. The more I dug around on the internet, the more horrified I became.  The wealth of information that clearly shows a lot of other folk out there have the same feelings about fibreglass insulation as me. So I've started to collate a few references for the record - and it's not pleasant reading:

Fibreglass:  Its otherwise known as rockwool - depends on what raw materials it starts life as.... Horrible stuff.  It's glass you see - and what does glass do - it gets steamed up and covered in condensation.  It breaks - that's why you find that your insulation gradually gets thinner and thinner in the loft space as it breaks down. Its called de-vitrification.. If you tread on it often enough, it flattens to nothing, and is useless. We spend half our time clearing out loft spaces of horrible old fibreglass insulation that has broken down.  If you use it in a wall, it does the same – it slowly slumps and breaks down. We see it all the time in surveys – that's what our little twisty, bendy cameras are for. Cavity insulation - forget it.

The most sinister thing about fibreglass insulation is that the industry trade bodies try to bully the world into thinking it isn't dangerous.  Every time we go into a loft space we see millions of horrible shining glass fibres floating around in the air.  As you walk, they puff up and swirl around in the torchlight.  I start to cough almost immediately.  If I don't wear full PPE, this starts a chain reaction of health problems which can go on for weeks. I've seen my doctor about it several times now - last time had very extensive testing for lung damage.  It's scarey when they talk about shadows, and put you in great big scanning machines.. It usually takes at least a month to get over each exposure to the damn stuff.  I've spoken to numerous surveyors who also have similar reactions - and nearly every homeowner I speak with refuses to even go into the loft if it is full of fibreglass.  I cannot over emphasise how horrible the reaction is when i get this stuff in my lungs - I had to be helped down the ladder once as I was coughing so much.  What do you think is happening to your lungs when they are stuck full of millions of spiky glass rods - you spend days scratching yourself after handling it - my clothes have to be washed several times, and even then you can still feel the damn stuff.   The Fire Service wont go near it without full breathing apparatus and PPE - a client of mine is a Health and Safety Officer with them, and told me never to go into a loft space without proper breathing apparatus. I've seen World Health Organisation reports that would make your toes curl (Although I tried to find it recently – funny how stuff gets supressed when it's controversial) There is a vast amount of literature and scientific research out there that compares fibreglass with asbestos.

This is just one random link to United States Health and Safety information online: Note the stark warning that goes with it:   "Reasonably Expected to be a Human Carcinogen"...  

And these industry bullies DARE to order me to take down the few words I originally posted about the nastiness of fibreglass.  

A few words about health research...

I've spoken to some very senior folk in the Health Industry.  How does research come about?  How do we collect data?  It all comes down to money.  Someone has to be funded to do the research, so it has to be worthwhile.  It is increasingly apparent that a lot of research is done by industry to show products are safe - trouble is, what happens when it actually shows a product is NOT safe.  There are countless examples of this 'cover up' mentality out there.  One of the main problems the health industry has is that they collect statistics based on current knowledge.  So if someone gets a tumour, or dies - unless it is known that they have been exposed to a particular product, it is never recorded.  So information about the long term danger of exposure to something is skewed and covered up - not intentionally, but simply because it wasn't seen as dangerous.  When medical researchers start to look at a product, they have little to go on - they didn't realise asbestos was dangerous for many, many years - nor cigarettes.  You wouldn't research the health effects of something if you didn't want it known it was dangerous either.  All the articles written on the dangers of fibreglass suffer from a lack of systematic data collection. It's been relatively easy to poke holes in research papers as a result.

[1] The following article was researched and authored by Rachel's Environment and Health Weekly, June 1, 1995 edition. It was published by the Environmental Research Foundation which provided the research and substance of this article. The ERF deserves your support for its commitment to a national environmental policy which makes health risks to people a national priority and for its commitment to public education. The ERF not only allows the re-distribution of its research and articles, but encourages it. We have the highest praise for ERF and its work. We encourage you to subscribe to Rachel's Weekly. Email, call 410.263.1584, or fax 410.263.8944:

Owens Corning's Fiberglas ®, Fiber Glass, Glass Fiber and Glass Wool: A Carcinogen That's Everywhere - The Asbestos of the 21st Century

An industrial process for making glass fibers was first patented in Russia in 1840. [1,pg.292] At the Columbian Exposition in Chicago in 1893, Edward Libbey, an American, exhibited lamp shades, a dress, and other articles woven from glass fibers. In 1915, the Allied Forces blockaded Germany and created an asbestos shortage which resulted in full-scale U.S. production of fiber glass as an asbestos substitute.

Asbestos is a naturally-occurring fibrous material that can be woven into cloth, does not burn readily, has excellent properties for thermal insulation, and therefore came into common commercial use during this century. [2,pgs.390-392] Fiber glass has many of the same characteristics as asbestos.

In 1938, the Owens Corning Fiberglas Company was formed, and three years later, in 1941, evidence of pulmonary disease was reported by Walter J. Siebert, who investigated the health of workers with the cooperation of Owens Corning.[1,pg.292] That same year another investigator reported finding "no hazard to the lungs" of workers exposed to glass fibers in the air. Scientific disagreement of this sort has characterized the study of fiber glass ever since; meanwhile fiber glass production has increased steadily.

In 1941, the U.S. Patent Office issued patents for 353 glass wool products. Glass wool, fiber glass, fiberglas, fibrous glass, and glass fibers are all names for the same thing: man made thin, needle-shaped rods of glass.

Fiber glass is now used for thermal insulation of industrial buildings and homes, as acoustic insulation, for fireproofing, as a reinforcing material in plastics, cement, and textiles, in automotive components, in gaskets and seals, in filters for air and fluids, and for many other miscellaneous uses. More than 30,000 commercial products now contain fiber glass.

As asbestos has been phased out because of health concerns, fiber glass production in the U.S. has been rising. In 1975, U.S. production of fiber glass was 247.88 million kilograms (545.3 million pounds); by 1984 it had risen to 632.88 million kilograms (1392.3 million pounds).[1,pg.302] If that rate of growth (10.4% per year) held steady, then production of fiber glass in the U.S. in 1995 would be 436 million pounds.

Fiber glass is now causing serious health concerns among U.S. officials and health researchers. Dr. Mearl F. Stanton of the National Cancer Institute found that glass fibers less then 3 microns in diameter and greater than 20 microns in length are "potent carcinogens" in rats; and, he said in 1974, "it is unlikely that different mechanisms are operative in man." A micron is a millionth of a meter (and a meter is about three feet). Since that time, studies have continued to appear, showing that fibers of this size not only cause cancer in laboratory animals, but also cause changes in the activity and chemical composition of cells, leading to changes in the genetic structure in the cellular immune system. Although these cell changes may be more common (and possibly more important) than cancer, it is the cancer-causing potential of glass fibers that has attracted most attention.

In 1970, Dr. Stanton announced that "it is certain that in the pleura of the rat, fibrous glass of small diameter is a potent carcinogen." The pleura is the outer casing of the lungs; cancer of the pleura in humans is called mesothelioma and it is caused by asbestos fibers. Stanton continued his research and showed that when glass fibers are manufactured as small as asbestos fibers, glass causes cancer in laboratory animals just as asbestos does. [4] Asbestos is a potent human carcinogen, which will have killed an estimated 300,000 American workers by the end of this century. [5] The finding that fiber glass causes diseases similar to asbestos was chilling news in the early 1970s, and an additional 25 years of research has not made the problem seem less serious. Workers in fiber glass manufacturing plants are exposed to concentrations of fibers far lower than the concentrations to which asbestos workers were exposed, yet several industry-sponsored epidemiological studies of fiber glass workers in the U.S., Canada, and Europe have reported statistically significant elevations in lung cancers. [6]

The International Agency for Research on Cancer (IARC), of the World Health Organization, listed fiber glass as a "probable [human] carcinogen" in 1987. In 1990, the members of the U.S. National Toxicology Program (NTP)-representatives of 10 federal health agencies-concluded unanimously that fiber glass "may reasonably be anticipated to be a carcinogen" in humans. NTP members were preparing to list fiber glass that way in the Seventh Annual (1992) Report on Carcinogens, the NTP's annual listing of cancer-causing substances, which is mandated by public law 95-622. But industry intervened politically.

Four major manufactures of fiber glass insulation campaigned for three years to prevent their product from being labeled a carcinogen by NTP. They managed to delay the publication of the NTP's Seventh Annual Report on Carcinogens for more than two years, but on June 24, 1994, the Secretary of Health and Human Services (HHS), Donna E. Shalala, signed the Report and sent it to Congress, thus making it official policy of the U.S. government that fiber glass is "reasonably anticipated to be a carcinogen." In the U.S., fiber glass must now be labeled a carcinogen.

Announcing this decision, government officials tried to play down its significance. Bill Grigg, a spokes-person for the U.S. Public Health Service (a subdivision of Health and Human Services) told the Washington Post, "There are no human data I'm aware of that would indicate there's any problem that would involve any consumer or worker." [7] To make such a statement, Mr. Grigg had to ignore at least six epidemiological studies showing statistically-significant elevations in lung cancers among production workers in fiber glass factories.[6] Indeed, according to researchers fiber glass is a more potent carcinogen than asbestos.[8,pg.580]

Fiber glass is now measurable everywhere in the air. The air in cities, rural areas,[1,pgs.311-314] and remote mountain tops [4] now contains measurable concentrations of fiber glass. If the dose-response curve is a straight line (that is to say, if half as much fiber glass causes half as much cancer) and if there is no threshold dose (no dose below which the cancer hazard disappears), then exposing the Earth's 5.7 billion human inhabitants to low concentrations of fiber glass will inevitably take its toll by causing excess cancers in some portion of the population.

According to OSHA researchers, an 8-hour exposure to 0.043 glass fibers per cubic centimeter of air is sufficient to cause lung cancer in one-in-every-thousand exposed workers during a 45-year working lifetime.[8,pg.580] In rural areas, the concentration of fiber glass in out-door air is reported to be 0.00004 fibers per cubic centimeter, about 1000 times below the amount thought to endanger one-in-every-thousand fiber glass workers.[1,pg.314] But people in rural areas breathe the air 24 hours a day, not 8 hours. Furthermore, a human lifetime is 70 years, not the 45 years assumed for a "work lifetime." Moreover, one-in-a-thousand is not adequate protection for the general public; U.S. Environmental Protection Agency uses one-in-100,000 or one-in-a-million as a standard for public exposures. (And in urban air, there's 10 to 40 times as much fiber glass as in rural air.) Therefore, the amount of fiber glass in the outdoor air in the U.S. and Europe (and presumably elsewhere) already seems higher than prudent public health policies would permit. Assuming a straight-line dose-response curve and no threshold, there is ample reason to be concerned about the human health hazards posed by fiber glass in the general environment.

It has been 25 years since researchers at the National Cancer Institute concluded that fiber glass is a potent carcinogen in experimental animals. During that ti me, additional research has confirmed those findings again and again.[8] During the same period, the amount of fiber glass manufactured has increased rapidly year after year. Ninety percent of American homes now contain fiber glass insulation. All of this fiber glass will eventually be released into the environment unless special (and very expensive) precautions are taken to prevent its release. The likelihood of Americans taking such precautions is nil. Billions of pounds of fiber glass now in buildings will eventually be dumped into landfills, from which it will leak out slowly as time passes. Elevated concentrations of fiber glass are already measurable in the air above landfills today.[4]

In 1991, Patty's Industrial Hygiene and Toxicology, a standard reference book on work-place safety and health, said about fiber glass, " is prudent for industrial hygienists to treat these materials with the same precautions as asbestos." [1,pg.324] How do we treat asbestos? In the U.S., all new uses of asbestos have been banned. A ban of fiber glass is long overdue.


  • [1] Jaswant Singh and Michael A. Coffman, "Man-Made Mineral Fibers," in George D. Clayton and Florence E. Clayton, editors, Patty's Industrial Hygiene and Toxicology Fourth Edition, Volume 1, Part B (New York: John Wiley & Sons, 1991),pgs. 289-327.

  • [2] Michael A. Coffman and Jaswant Singh, "Asbestos Management in Buildings," in George D. Clayton and Florence E. Clayton, editors, Patty's Industrial Hygiene and Toxicology Fourth Edition, Volume 1, Part B (New York: John Wiley & Sons, 1991), pgs. 387-420.

  • [3] The Annual List of carcinogens is drawn up by an inner-agency Working Group for the Annual Reports on Carcinogens, which includes representatives from the Agency for Toxic Substances and Disease Registry (ATSDR); the Centers for Disease Control (CDC); the National Institute for Occupational Safety and Health (NIOSH); the Consumer Product Safety Commission (CPSC); the U.S. Environmental Protection Agency (EPA); the Food and Drug Administration (FDA); the National Cancer Institute (NCI); the National Institute o f Environmental Health Sciences (NIEHS); the National Library of Medicine (NLM); and the Occupational Safety and Health Administration (OSHA).

  • [4] Reported in Katherine and Peter Montague, "Fiber Glass," Environment Vol. 16 (September 1974), pgs. 6-9.

  • [5] Philip J. Landrigan, "Commentary: Environmental Disease-A Preventable Epidemic," American Journal of Public Health Vol. 82 (July 1992), pg. 941.

  • [6] See Peter F. Infante and others, "Fibrous Glass and Cancer," American Journal of Industrial Medicine Vol. 26 (1994), pgs. 559-584, which reviews the following studies, among others: L. Simonato and others, "The International Agency for Research on Cancer Historical Cohort of MMMF Production Workers in Seven European Countries Extension of the Follow-Up," Annals of Occupational Hygiene Vol. 31, No. 4B (1987), pgs. 603-623; Philip E. Enterline and others, "Mortality Update of a Cohort of U.S. Man Made Mineral Fibre Workers," Annals of Occupational Hygiene Vol. 31, No. 4B (1987), pgs. 625-656; Harry S. Shannon and Others, "Mortality Experience of Ontario Glass Fibre Workers-Extended Follow-UP," Annals of Occupational Hygiene Vol.31, No. 4B (1987), pgs. 657-662; and John R. Goldsmith, "Comparative Epidemiology of Men Exposed to Asbestos and Man-Made Mineral Fibers," American Journal of Industrial Medicine Vol. 10 (1986), pgs. 543-552; G.M. Marsh and Others, "Mortality Among a Cohort of US Man-Made Mineral Fiber Workers : 1985 Follow-Up," Journal of Occupational Medicine Vol. 32 (1990), pgs. 594-604; P. Boffetta and others, "Lung Cancer Mortality Among Workers in the European Production of Man-Made Mineral Fibers-A Poisson Regression Analysis," Scandinavian Journal of Work, Environment, and Health Vol. 18 (1992), pgs. 279-286.

  • [7] Frank Swoboda and Maryann Haggerty, "U.S. Suspects Figerglass as Carcinogen, Calls Insulation Safe," Washington Post July 2, 1994, pg. C1.

  • [8] Peter F. Infante and others, "Fibrous Glass and Cancer," American Journal of Industrial Medicine Vol. 26 (1994), pgs. 559-584 lawyers san jose, san francisco attorneys, personal injury, personal injury lawyers palo alto, brain injury, toxics, chemicals, cancer, brain cancer, santa clara, stanford, mountain view."


Funny how the British Government is still pushing fibreglass loft insulation - its really green and carbon efficient - takes a furnace heated to 1800 degrees C to make it, and vast amounts of energy to fuel the furnace.. Seriously green, this stuff - takes billion dollar multinational chemical companies to make it - in massive chemical plants.  

Another issue with fibreglass is formaldehyde - now banned by the EU in building products - this is an exerpt from the Health Living Institute website in the United States:

"Residential fiberglass batt insulation contains about 5% resin binder that is capable of outgassing formaldehyde fumes into the air. The pink colored insulation manufactured by Owens-Corning Fiberglas Corporation contains, in addition, about 1% dye that has its own outgassing characteristics. The resin used in insulation is usually a phenol-formaldehyde product, but Manville Corporation uses a urea-extended phenol-formaldehyde resin, which outgasses at a faster rate. Of the major insulation manufacturers, the batt insulation produced by Certainteed Corporation, with 4% phenolformaldehyde resin and no dye, is probably the least potent from an outgassing standpoint, however, it can still bother people sensitive to formaldehyde.

When resin coated fiberglass enters the sinuses or the lungs, there is the possibility that the resin could react with the soft tissues and cause inflammation or damage. It is known that formaldehyde based resins decompose when exposed to heat and humidity, yet no research has been done to explore this mode of exposure"

Info on formaldehyde - really nice stuff this - and part of fibreglass manufacturing:

Fibreglass - it is horrible in every way imaginable - my chest hurts, my eyes get red and painful, my arms and hands sting, my clothes are full of it - and that's just from a trip into someone's loft..

My advice, based on personal experience, and that of my colleagues who experience similar reactions: Don't go near fibreglass. Treat it with the respect that any highly toxic and dangerous substance deserves. There are better and much more eco-friendly products out there that do the same job of insulating your home.

Makes a few farting sheep with their wool on a hillside SO nice and green, and comfy, and safe doesn't it!  

Foam Insulation:  There are various foam based insulations all made using isocyanate polymers of one form or another.  The commonest is called Kingspan, and one of the worst I have ever come across is that spray foam they try to sell you for underneath your roof. Sprayfoam on the roof is the kiss of death to your roof - it creates a totally sealed environment around the laths that hold the slate or tile on, and they start to rot immediately because so much moisture is trapped by the foam.  It also sticks all the slate or tiles together so they cannot be maintained or repaired.  The net result is that any roof with sprayfoam insulation is essentially scrap and needs to be replaced.  Foam sheets, covered with foil are a magnet for condensation and trap moist air into a building.  I've seen roof areas with water literally running down the foam boards.  It is used underneath floors as insulation, where again, it is prone to condensation.  Dont use it for anything in an old building that needs to breathe.  If an architect specifies it, refuse to have it. Nearly all the external and internal wall insulation that is being flogged out there is made of this - and we are seeing numerous examples of sopping wet walls as a result of EWI and IWI.  

Fortunately, there is a whole new world of breathable, carbon friendly insulation materials out there which are freely available.  The following pages detail the ones that we work with regularly, and are now tried and proven.  They are all essentially similar - they are natural, non-chemical, green, carbon friendly, and BREATHABLE!  In winter, my guys wander around on site with a length of sheepswool insulation around their neck for a scarf - its beautiful stuff.


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