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| UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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Mineral wool or polystryene for cavity walls
I recently got a flyer through the letterbox from a company wanting to take
advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob |
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"Bob Smith (UK)" bob@nospamplease wrote in message ... I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob Still think this type is best http://www.ncia-ltd.org.uk/page4.asp for the money. |
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"Bob Smith (UK)" bob@nospamplease wrote in message ... I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Is this cavity wall insulation? _________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download http://www.usenetzone.com to open account |
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On Wed, 8 Jun 2005 17:40:25 +0100, "Bob Smith \(UK\)"
bob@nospamplease wrote: I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob IMO it's the best. No chemicals. No smell. I've had it for about 10 years now without any problems whatsoever. I even had it injected from the inside on the front of the house because I didn't want the very narrow pointing damaged. I can't commment on current costs I'm afraid. Andy |
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"Andy Pandy" wrote in message ... On Wed, 8 Jun 2005 17:40:25 +0100, "Bob Smith \(UK\)" bob@nospamplease wrote: I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob IMO it's the best. No chemicals. No smell. I've had it for about 10 years now without any problems whatsoever. I even had it injected from the inside on the front of the house because I didn't want the very narrow pointing damaged. I can't commment on current costs I'm afraid. I agree - I've had mineral wool insulation now for about eight years. No problems at all. Polystyrene insulation, AIR , is injected as small 'balls' together with a binding 'glue' which is supposed to stick them together. I remember reading one or two articles, however, where people who have had this type of insulation have knocked a hole in the cavity wall (eg to put a vent pipe from a tumble-dryer through) and a huge pile of polystyrene balls have just poured out of the hole onto the floor! Kev |
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#7
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In message ,
"Uno Hoo!" wrote: "Andy Pandy" wrote in message ... On Wed, 8 Jun 2005 17:40:25 +0100, "Bob Smith \(UK\)" bob@nospamplease wrote: I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob IMO it's the best. No chemicals. No smell. I've had it for about 10 years now without any problems whatsoever. I even had it injected from the inside on the front of the house because I didn't want the very narrow pointing damaged. I can't commment on current costs I'm afraid. I agree - I've had mineral wool insulation now for about eight years. No problems at all. Polystyrene insulation, AIR , is injected as small 'balls' together with a binding 'glue' which is supposed to stick them together. I remember reading one or two articles, however, where people who have had this type of insulation have knocked a hole in the cavity wall (eg to put a vent pipe from a tumble-dryer through) and a huge pile of polystyrene balls have just poured out of the hole onto the floor! On a related note, we're trying to scrape together money to cavity insulate our 1930s ex-council semi. Most of the house is brick/cavity/brick/render and there are vent bricks into this cavity (solid ground floor) in several places at the top and bottom of each wall, and the cavity is open to the loft space. Since one of the functions of cavity fill would be to stop airflow through the cavity is this likely to cause us any problems? Not convinced about the fastness of the exterior skin to penetrating damp either so I'm not too keen on mineral fibre fill, favouring expanding foam at the moment. Does the panel have any opinion on the matter? Hwyl! M. -- Martin Angove: http://www.tridwr.demon.co.uk/ Two free issues: http://www.livtech.co.uk/ Living With Technology .... NetWare does not have bugs, it has "Undocumented enhancements" |
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Bob Smith (UK) wrote:
I recently got a flyer through the letterbox from a company wanting to ta= ke advantage of grants to insulate private homes. They say they will insula= te my house with mineral wool for =A3150, and that it is =A3400 without the = grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, d= oes mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob polystyrene can cause damp problems, it saturates with water. Also it contains plsticisers. And when it contacts pvc cables (only in houses where pvc cable is in the cavity) the cable turns to goo. NT |
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On Wed, 08 Jun 2005 23:04:53 +0100, Martin Angove
wrote: On a related note, we're trying to scrape together money to cavity insulate our 1930s ex-council semi. Most of the house is brick/cavity/brick/render and there are vent bricks into this cavity (solid ground floor) in several places at the top and bottom of each wall, and the cavity is open to the loft space. Since one of the functions of cavity fill would be to stop airflow through the cavity is this likely to cause us any problems? Not convinced about the fastness of the exterior skin to penetrating damp either so I'm not too keen on mineral fibre fill, favouring expanding foam at the moment. Does the panel have any opinion on the matter? Hwyl! M. I'm not expert but surely *any* cavity fill will stop air circulation - that's the whole point, the vital quality is that it doesn't tansmit moisture. As for the air bricks they are removed and the hole lined with wool fibre to create a tube, prior to filling. The open top is not a problem but you might find some fill along the edges of your loft space. Why should the exterior skin get any wetter than if there was no coating at all ? Andy |
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On Wed, 8 Jun 2005 17:40:25 +0100, "Bob Smith \(UK\)"
bob@nospamplease wrote: I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob I looked into this, In a cavity you need "cavity grade" mineral wool, which has been treated to stop moisture transfer, then you can "full fill" the cavity. Polystyerine sheets are not graded fro "full fill". There is one company in ireland that makes full fill polystyerine. The puzzle is how do you get either of these into a cavity once the house is built ? Rick |
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In message ,
Andy Pandy wrote: On Wed, 08 Jun 2005 23:04:53 +0100, Martin Angove wrote: On a related note, we're trying to scrape together money to cavity insulate our 1930s ex-council semi. Most of the house is brick/cavity/brick/render and there are vent bricks into this cavity (solid ground floor) in several places at the top and bottom of each wall, and the cavity is open to the loft space. Since one of the functions of cavity fill would be to stop airflow through the cavity is this likely to cause us any problems? Not convinced about the fastness of the exterior skin to penetrating damp either so I'm not too keen on mineral fibre fill, favouring expanding foam at the moment. Does the panel have any opinion on the matter? Hwyl! M. I'm not expert but surely *any* cavity fill will stop air circulation - that's the whole point, the vital quality is that it doesn't tansmit moisture. As for the air bricks they are removed and the hole lined with wool fibre to create a tube, prior to filling. Why? The open top is not a problem but you might find some fill along the edges of your loft space. So long as it doesn't prevent airflow throught the eaves. Why should the exterior skin get any wetter than if there was no coating at all ? I don't know what the air bricks are for. In my naivety I assumed that perhaps the cavity *needs* to be ventilated for reasons of losing any damp which might have penetrated the outer skin? Now given that we're not likely to be doing anything to the outer skin other than (perhaps) painting it, two potential problems presented themselves: 1: since cavity fill stops the airflow, any damp which *does* penetrate the outer skin will find it more difficult to evaporate. 2: any penetrating damp will find itself next to the insulation. I gather that mineral fibre can be quite good at wicking, and hence wondered about this dampness crossing to the inner skin. I may be worrying for no reason at all, but I know that mum & dad, who had cavity insulation back in the 1980s of the glued polystyrene kind (I think) had very bad penetrating damp problems on one wall for ages afterwards until they had that wall rendered and pebbledashed. Just came here for opinions, that's all :-) Hwyl! M. -- Martin Angove: http://www.tridwr.demon.co.uk/ Two free issues: http://www.livtech.co.uk/ Living With Technology .... Divers do it better under pressure. |
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#14
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"Rick" wrote in message ... On Wed, 8 Jun 2005 17:40:25 +0100, "Bob Smith \(UK\)" bob@nospamplease wrote: I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob I looked into this, In a cavity you need "cavity grade" mineral wool, which has been treated to stop moisture transfer, then you can "full fill" the cavity. Polystyerine sheets are not graded fro "full fill". There is one company in ireland that makes full fill polystyerine. The puzzle is how do you get either of these into a cavity once the house is built ? See my post above. The polystyrene is in the form of 'granules' or little balls - and is injected together with a binding glue to stick it all together. Kev |
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On Thu, 09 Jun 2005 09:08:37 +0100, Martin Angove
wrote: I'm not expert but surely *any* cavity fill will stop air circulation - that's the whole point, the vital quality is that it doesn't tansmit moisture. As for the air bricks they are removed and the hole lined with wool fibre to create a tube, prior to filling. Why? Because their purpose is to ventilate the rooms or beneath the floor, which is why there's an air brick in each skin. The open top is not a problem but you might find some fill along the edges of your loft space. So long as it doesn't prevent airflow throught the eaves. True. Why should the exterior skin get any wetter than if there was no coating at all ? I don't know what the air bricks are for. In my naivety I assumed that perhaps the cavity *needs* to be ventilated for reasons of losing any damp which might have penetrated the outer skin? Now given that we're not likely to be doing anything to the outer skin other than (perhaps) painting it, two potential problems presented themselves: 1: since cavity fill stops the airflow, any damp which *does* penetrate the outer skin will find it more difficult to evaporate. 2: any penetrating damp will find itself next to the insulation. I gather that mineral fibre can be quite good at wicking, and hence wondered about this dampness crossing to the inner skin. I may be worrying for no reason at all, but I know that mum & dad, who had cavity insulation back in the 1980s of the glued polystyrene kind (I think) had very bad penetrating damp problems on one wall for ages afterwards until they had that wall rendered and pebbledashed. I think there were endless problems with early foam. I don't think it can be compared to products with a reasonable proven service life. Just came here for opinions, that's all :-) Hwyl! If I'm wrong no doubt you'll hear about it soon enough. :-) Personally, I wouldn't hesitate to have it done. I'm convinced it's had an appreciable benefit on my fuel bills, though against the background of a more favourable climate I admit. Andy |
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In message ,
Andy Pandy wrote: On Thu, 09 Jun 2005 09:08:37 +0100, Martin Angove wrote: I'm not expert but surely *any* cavity fill will stop air circulation - that's the whole point, the vital quality is that it doesn't tansmit moisture. As for the air bricks they are removed and the hole lined with wool fibre to create a tube, prior to filling. Why? Because their purpose is to ventilate the rooms or beneath the floor, which is why there's an air brick in each skin. But there aren't. There is no corresponding air brick on the inner skin *anywhere* in the house, and as I said we're talking about several top and bottom on each external wall. There is no sign that any have been removed / blocked up / whatever either. The lower bricks are at or below the level of the ground floor slab, and the upper bricks are a couple of courses below eaves level. Actually, come to look at it, there aren't top air bricks on every wall, but as I said the cavity is open at the top anyway. In that case isn't it more likely that they are for ventilating the cavity? Some houses in the street have had a very thick external render applied (expanding-foam-like substance visible in places) which is presumably an external insulator. These appear to have had the top air bricks rendered over; it's a bit difficult to see the lower ones without wandering into front gardens :-) [...] Hwyl! M. -- Martin Angove: http://www.tridwr.demon.co.uk/ Two free issues: http://www.livtech.co.uk/ Living With Technology .... Beware of Geeks bearing GIFS |
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The Natural Philosopher wrote:
wrote: Bob Smith (UK) wrote: I recently got a flyer through the letterbox from a company wanting to = take advantage of grants to insulate private homes. They say they will insu= late my house with mineral wool for =A3150, and that it is =A3400 without th= e grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie,= does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? polystyrene can cause damp problems, it saturates with water. Eh? Polystyrene impervious to water. Polystyrene foam is expanded, meaning its full of air pockets. Theyre not closed cells, so its porous. If air reaches dew point, condenastion will occur and fill the poly foam. Saturation of foam is a problem in fridges and freezers. There is such thing as marine grade, which is closed cell, but it costs more. NT |
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Martin Angove wrote:
In message , Andy Pandy wrote: On Thu, 09 Jun 2005 09:08:37 +0100, Martin Angove wrote: I'm not expert but surely *any* cavity fill will stop air circulation - that's the whole point, the vital quality is that it doesn't tansmit moisture. As for the air bricks they are removed and the hole lined with wool fibre to create a tube, prior to filling. Why? Because their purpose is to ventilate the rooms or beneath the floor, which is why there's an air brick in each skin. But there aren't. There is no corresponding air brick on the inner skin *anywhere* in the house, and as I said we're talking about several top and bottom on each external wall. There is no sign that any have been removed / blocked up / whatever either. The lower bricks are at or below the level of the ground floor slab, Ther are for underfloor b=ventilation - below damp course usually. and the upper bricks are a couple of courses below eaves level. They may well be to ventilate the roof space. You can do the same job by putting holes in the soffits. Actually, come to look at it, there aren't top air bricks on every wall, but as I said the cavity is open at the top anyway. To ventilate the roof...? |
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On Thu, 09 Jun 2005 15:47:53 +0100, The Natural Philosopher
wrote: Ah. Now I understand why polystyrene foam is used for things like bouys and filling boats. It helps them get waterlogged, and sink. Waterlogged polystyrene foam doesn't have _much_ water in it. It will still float. However it would now make an excellent heat leak if you expected it to still be an insulator. |
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In message ,
The Natural Philosopher wrote: Martin Angove wrote: But there aren't. There is no corresponding air brick on the inner skin *anywhere* in the house, and as I said we're talking about several top and bottom on each external wall. There is no sign that any have been removed / blocked up / whatever either. The lower bricks are at or below the level of the ground floor slab, Ther are for underfloor b=ventilation - below damp course usually. Except that according to our surveyor (actually a friend who is an NHBC inspector etc.) and our builders (who did some extensive work for us including removing a chimney brest) our floor is concrete on hardcore (of some description, probably ash) on earth. Probably no DPC at all. In fact surveyor friend said that if it were his house the first thing he'd do would be to dig up the floor and re-lay it with DPC and insulation. and the upper bricks are a couple of courses below eaves level. They may well be to ventilate the roof space. You can do the same job by putting holes in the soffits. No soffits; eaves are open around most of the roof. Actually, come to look at it, there aren't top air bricks on every wall, but as I said the cavity is open at the top anyway. To ventilate the roof...? Hmmm... whatever. Reckon I'm going to have to get quotes from a couple of companies and see if they differ in their survey :-/ Spoke to man from the council who expressed surprise when I told him that neighbouring houses appeared to have had external insulation applied (these are all ex-council BTW). He told me another interesting thing though, apparenly the council only approves mineral fibre or polystyrene; nothing else (for retrofit applications anyway). Hwyl! M. -- Martin Angove: http://www.tridwr.demon.co.uk/ Two free issues: http://www.livtech.co.uk/ Living With Technology .... There's nothing quite so wonderful as money. |
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The Natural Philosopher wrote:
wrote: polystyrene can cause damp problems, it saturates with water. Eh? Polystyrene impervious to water. Polystyrene foam is expanded, meaning its full of air pockets. Theyre not closed cells, so its porous. If air reaches dew point, condenastion will occur and fill the poly foam. Saturation of foam is a problem in fridges and freezers. There is such thing as marine grade, which is closed cell, but it costs more. Ah. Now I understand why polystyrene foam is used for things like bouys and filling boats. It helps them get waterlogged, and sink. Silly lad, they use marine grade for that, which is closed cell. Same for those float boards kids use in pools. NT |
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bigcat wrote:
The Natural Philosopher wrote: bigcat wrote: polystyrene can cause damp problems, it saturates with water. Eh? Polystyrene impervious to water. Polystyrene foam is expanded, meaning its full of air pockets. Theyre not closed cells, so its porous. If air reaches dew point, condenastion will occur and fill the poly foam. Saturation of foam is a problem in fridges and freezers. There is such thing as marine grade, which is closed cell, but it costs more. Ah. Now I understand why polystyrene foam is used for things like bouys and filling boats. It helps them get waterlogged, and sink. Silly lad, they use marine grade for that, which is closed cell. Same for those float boards kids use in pools. Erm, it's too late for April Fools, try again next year. |
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#25
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"Doctor Evil" wrote in message ... "Bob Smith (UK)" bob@nospamplease wrote in message ... I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Is this cavity wall insulation? Yes. The reply by BigWallop included a link to a site detailing the 3 main types of insulation. It says all 3 types do not conduct water, although they are not vapour barriers. Bob |
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"BigWallop" wrote in message k... "Bob Smith (UK)" bob@nospamplease wrote in message ... I recently got a flyer through the letterbox from a company wanting to take advantage of grants to insulate private homes. They say they will insulate my house with mineral wool for £150, and that it is £400 without the grant. Is it any better than polystyrene? Does mineral wool conduct damp, ie, does mineral wool "bridge" damp proof courses. I know polystyrene does not conduct damp. Also, what would be the cost difference? Thanks Bob Still think this type is best http://www.ncia-ltd.org.uk/page4.asp for the money. Thanks for the link. It seems all 3 types have much the same qualities, and the same insulation value, with each having one unique quality (UF foam makes formaldehyde, EPS balls blow into the loft and must be cleared up). I read somewhere the blown mineral fibres have to be treated to stop damp conduction. I can imagine it will settle over time as well. Bob |
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