Fibreglass how good is it for insulation.

  Ex plorer 10:25 12 Nov 2012

Hi just how good is fibreglass insulation.

I was in the plumbing and heating trade from leaving school in 1962 for around twenty five years. As I live in the dales solid fuel and later oil was the only way to heat our houses.

I remember the first time I insulated a loft with one inch fibreglass.

A few years latter one inch went out and double wrap (one inch doubled over) came in around two inches thick and became the standard insulation.

In later years it was four inch and if I remember right it was two inch just doubled as it could be split into the old two inch with ease.

Then eight inch was introduced as the standard.

Now ten inches when will it stop.

My roof still has vermiculite in the attic a small cork granular substance around three inches and seems to work as snow and frost does stay on the roof.

Fiberglass is messy and cumbersome, and dirty stuff surely there are better products today.

The old four inch was perfect as it sat between the timbers and you could see where you were putting your feet.

Today Wall cladding insulation is only a few inches thick as it is for under floor heating would this not be a better move to the attic.

Why are we still stuck with fiberglass in the lofts getting thicker every several years it takes up space and storage in conventional lofts.

  spuds 12:06 12 Nov 2012

Like all these energy and eco-saving products nowadays, it pays to get the latest information, because expert views are changing all the time.

A number of years ago, we had the cavity wall and loft insulation done, but the regular cold callers are always telling us that we should have something far better. I still wonder how they will remove the old product from between the wall cavities, so as to install the latest specification superior product?.

  oresome 13:25 12 Nov 2012

You ask when will the standards stop being raised.

The answer to that is when we have a plentiful supply of cheap energy. That's never likely to be the fact energy costs are more likely to continue rising in real terms driving the need to conserve as much as we can.

The thickness of the insulation is only a problem to those who use the loft for other purposes. There are probably more effective solutions which cost more to purchase and to lay where this a problem, but I expect most people wouldn't want to pay the difference.

  Forum Editor 14:59 12 Nov 2012

There are alternatives to what is called 'mineral wool' insulation for lofts. An excellent substitute is a product that looks fairly similar, and comes on a roll, but is actually made from recycled plastic bottles. It's soft, easy to handle, non-irritant, and has excellent insulation properties.

The important thing to bear in mind with whatever you use is that it must comply with BS EN 13501-1 and/or be classified as Euroclass A1 as far as reaction to fire is concerned.

On a 200mm thick mat you should expect to see an R value of 4.50m2K/W

Generally speaking with this kind of insulation the thicker it is, the better the insulation value. Other,thinner materials are available that have high insulation values, but they are not really suitable for lofts where you need to walk on the joist tops. They consist of a blanket sandwich of layers of metallic foil and polythene, and are used extensively to insulate the inner side of roof pitches in loft conversions. They come in wide rolls, and are stapled to the underside of the roof joists before plasterboards are fixed. A blanket of this type approximately 15mm thick has the same insulation value as a 120mm high density polystyrene slab. It's expensive stuff, but it is very clean and easy to cut and fit, and of course it occupies very little space. You could put it on the loft floor if you were planning to board the floor afterwards.

  wee eddie 15:14 12 Nov 2012

I know that this is riding onto someone else's thread but:

I insulated the open part of my loft, a couple of years back, but left the part that was boarded over as I did not know how to do that without lifting all the boards.

Anyone know how this could be done, fairly simply, without lifting the boards?

  Ex plorer 15:29 12 Nov 2012

Hi fiberglass seems to act like a sponge in water it will absorb the heat and slow the heat loss not stop it, as it proves we have gone from one inch to ten inches in around forty years.

Chronos the 2nd, interesting link thanks.

Spuds, Ah yes probably use a solvent who knows, but dose the cost to replace really pay.

oresome, I reckon it will pay for the best now if you are having a new build and have an option on your insulation type, I reckon you have to price on your age today and if it will give you full benefit over the years to come.

I want to replace like for like double glazing in my house at 65years young will it pay me to do so. The front wants five windows at £3.220.00 back of house will have to wait.

If I have my sums right in twenty years time it will have cost me £13.33 a month, god willing I live till then. I suppose it depends on the price of energy in the future. Including the back of house around £19.75 per month.

My cost on oil 2010 to 2011 was around £1.000 This year around £60 more.

  Ex plorer 15:44 12 Nov 2012

wee eddie I have seen what they use for under floor heating very thick insulation board. You could lay that on the boards and cover with thin ply-wood or any kind of boarding and screw down to the the original floor.

  Forum Editor 16:12 12 Nov 2012

wee eddie

The product mentioned by Ex plorer (insulation boards for underfloor heating) would certainly work in your situation. They are intended for laying on a floor prior to the installation of electrical heating grids, and minimise heat loss into the sub-floor.

These boards are designed to be tiled over, but there's no reason you couldn't cover them with high-density chipboard loft flooring panels. It's not a cheap solution, but it would provide you with a very nice, well-insulated loft floor.

  wee eddie 17:58 12 Nov 2012

No one know of any granule type thingy that I could blow into the space then.

  woodchip 18:57 12 Nov 2012

vermiculite is no good as it blows away if there is any draft, wind, a lot of the slab stuff sold at builders is the best kind if you can get it in the loft and its best for walls

  woodchip 18:59 12 Nov 2012

Slab Insulation


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