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I wish to insulate the space between the rafters on my home,

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whjich has had an 'informal'...
I wish to insulate the space between the rafters on my home, whjich has had an 'informal' loft conversion carried out by the previous owners, and therefore does not have any insulation. I have been told about a new american product called ISU which is supposed to be very efficient and does not need to be anywhere near as thich to obtain similar insulation values to more traditional materials ( I have only 3"x3" oak rafters). However, I cannot find any link to such a product. Do you know of it and does it go under another name? I live in UK but I understand this product is now available in UK.
Submitted: 8 years ago.Category: Home Improvement
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6/17/2010
Home Improvement Expert: Rick, General Contractor replied 8 years ago
Rick
Rick, General Contractor
Category: Home Improvement
Satisfied Customers: 24,574
Experience: Licensed construction supervisor with 35+ yrs. experience.
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Hi

I haven't heard of any insulation product referred to as ISU. The rigid foam board insulation that has the highest R value is Polyisocyanurate. Perhaps this is the product you heard about. It is widely available here in the States and is generally referred to as high R insulation. It is typically a dirty yellow color and usually has a foil face.
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Home Improvement Expert: Rick, General Contractor replied 8 years ago
You might also consider a radiant barrier in addition to the rigid foam insulation. These typically look like the bubble wrap packing material with a foil face. You would install it as a final layer on the living space side of the insulation.
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Customer reply replied 8 years ago
Hi Rick

We also have this product in UK, goes by the name of Celotex, but this is not the product I am seeking, although I may have to use it if I cannot get anymore information on this ISU product. It was mentioned by a tiling contractor who said it had been introduced into UK about two years ago but that not many people had heard of it yet (obviously, hence my difficulty in finding a reference to it) Apparently it is only about 1" thick and has the same R value as 4" Celotex but is significantly more expensive. I am wondering if it is some form of PU panel (sealed vacuum panels) as used in high tech refrigeration units, especially for boats etc eg Glacier Bays 'R' panels. I know they are horrendously expensive as I looked at them with a view to insulating a refrigerated icebox on my sailboat, just for that I was looking at around $2000~$3000 so obviously I rejected that idea!
Home Improvement Expert: Rick, General Contractor replied 8 years ago
If there was a product that legitimately had 4 times the R value of Celotex it would likely be a sensation and you wouldn't have any trouble finding it. There have been numerous claims for new insulation products that don't hold up under scrutiny. The product that has the highest R value/thickness ration is the radiant barrier products but their R value doesn't increase with additional thickness.
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Customer reply replied 8 years ago
I didn't say it had 4 times the insulation value, I said it had the same R value as 4" Celotex (not the same thing at all) however just for your information the Glacier Bay 'R' panels claim to have around 20X the insulation value of PU foams, hence the horrendous price ( around $600~$700 for a 2square foot panel) They are also quite fragile as they are sealed in milar plastic and if this is puntured, the insulation value is drastically reduced. As I understand it, insulation panels have a finite insulation where eventually adding extra thickness of the same material has less and less effect until eventually having negligible/no effect affect on improving the insulation. As an example 8" celotex is about as much as you are ever going to need to get maximum insulation. Adding another 8" would have negligible affect, therfore if I can find a product (ISU) that has similar values to 4" Celotex (which I cannot use due to aforementioned space restrictions) then I will comply with current reccomendations of a minimum of 4" insulation based on using Rockwool or Fibreglass insulation. I f you have not heard of ISU then you have not / cannot answer my question and should not have accepted it.

Regards

Martin
Home Improvement Expert: Rick, General Contractor replied 8 years ago
I'll opt out. Maybe one of our other experts can help
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