Its a real mystery isn't it mattylad!
Celotex Alternatives? Without Mobile/Wifi sapping properties
- Thread starter soflo
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More usually the use of foil-backed insulation in floors, walls and roofs of buildings actually improves the Wi-Fi signal internally by mirroring the signal (the type of transmitter and antenna used can affect this) but external signals such as 3G and FM can be decimated. If it is used for internal walls and ceilings it can cause problems with the Wi-Fi coverage too.
A friend lives in a self-build barn conversion and their living room gets 2 bars of 3G signal and excellent Wi-Fi but if you go into their bathroom and close the doors the 3G signal disappears and the Wi-Fi is barely detectable despite the transmitter being on the opposite side of the wall. Although all the external walls were lined internally with foil-backed insulation all the internal walls used fibre wadding - except for the bathrooms which used foil-backed insulation. (The rooms are next to each other on the same external wall and the living room has a large amount of glazing.) It is only observed evidence here - the proof would be in removing the bathroom walls and rebuilding with different insulation - but it is one heck of a coincidence.
To the OPs question - you can buy Kingspan with glass tissue facings instead of foil which are commonly used on warm flat roofs where the top will be covered with felt or resin. The thermal conductivity is not quite as low without the foil (e.g. 0.026 W/m.K for 80mm versus 0.02 W/m.K) but it may be acceptable for your requirements. I expect the other insulation manufacturers probably sell similar products.
A friend lives in a self-build barn conversion and their living room gets 2 bars of 3G signal and excellent Wi-Fi but if you go into their bathroom and close the doors the 3G signal disappears and the Wi-Fi is barely detectable despite the transmitter being on the opposite side of the wall. Although all the external walls were lined internally with foil-backed insulation all the internal walls used fibre wadding - except for the bathrooms which used foil-backed insulation. (The rooms are next to each other on the same external wall and the living room has a large amount of glazing.) It is only observed evidence here - the proof would be in removing the bathroom walls and rebuilding with different insulation - but it is one heck of a coincidence.
To the OPs question - you can buy Kingspan with glass tissue facings instead of foil which are commonly used on warm flat roofs where the top will be covered with felt or resin. The thermal conductivity is not quite as low without the foil (e.g. 0.026 W/m.K for 80mm versus 0.02 W/m.K) but it may be acceptable for your requirements. I expect the other insulation manufacturers probably sell similar products.
I see you're being as charming and intelligent as ever
In what way are you saying I have no actual evidence ? I guess the customer I cited where we had actual problems was just an illusion then, or perhaps a figment of my muppet mind ?
The simple facts are that a large foil sheet will block radio signals at the frequencies being discussed. That does not mean you won't have a signal as there are a lot of variables - size and location of gaps being one important factor. Bear in mind that the wavelength of GSM 900MHz signals is in the order of around a foot, about half that at 1800MHz. For 2.4G WiFi it's around 5", and for 5.8G it's around half that. Which means you are going to have some interesting effects from radio signals passing through narrow slots where (for example) slabs of insulation are fitted between wooden battens/studs.
And for the record, I'm also quite familiar with the problems of getting radio waves (2.4 and 5.8G) through thick walls in old buildings. Interestingly 5.8G can give better coverage as whilst it may seem like it should be absorbed more passing through walls (it is), it also tends to diffract & reflect about a bit more than 2.4G so you may find you get coverage curtesy of doorways etc when you might expect none due to the thick wall. But nothing beats actually trying it out and checking to see what coverage actually happens.
But since it's only part of the day job, why should I know anything about it ? And I guess having been involved (with a previous hat on) in electronic equipment design and EMC testing (the reverse of trying to get good radio propagation) is irrelevant too ?
What a load of tosh.
I think there are currently a billion homes in the western world furnished with foil backed insulation and probably a half billion of those in the U.S.
Jeepers some people are naive.
I think there are currently a billion homes in the western world furnished with foil backed insulation and probably a half billion of those in the U.S.
Jeepers some people are naive.
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Hmm, I think someone is exaggerating a teensy little bit.
500 million homes in the USA insulated with foil backed boards eh ? If (say) half of all homes were insulated like that (probably on the high side when you consider how much old stock they have (like us) - then that would mean in the order of 3 homes per head of population
500 million homes in the USA insulated with foil backed boards eh ? If (say) half of all homes were insulated like that (probably on the high side when you consider how much old stock they have (like us) - then that would mean in the order of 3 homes per head of population
Oh ok, what about a trillion?
How about a Centillion? If you thought about all the zeros that number involves your little brain would go bang!
Now that's charming!
Isn't a Googleplex the highest number known to man?
Although my O/H - whose got a degree in maths - tells me you can have small infinity, and big infinity...
The point i was making is that there aren't just a few homes and businesses with a complete foil shell but there are millions.
The repercussions would be crushing and the whole wi-fi world would end.
But it hasn't.
So what these muppets are saying is absolute tosh.
The repercussions would be crushing and the whole wi-fi world would end.
But it hasn't.
So what these muppets are saying is absolute tosh.
Thank you very much for the suggestions Mattylad & xDave.
xDave – is the product you mean this one? Thermaroof TR27 LPC/FM
There is alot of evidence of people with similar issues out there - try Googling for ‘foil backed insulation mobile reception’ & ‘foil backed insulation wifi’
http://www.pcpro.co.uk/blogs/2011/04/14/whats-killing-your-wi-fi-wrapping-your-house-in-tin-foil/
http://www.greenbuildingadvisor.com...-building-products-block-cell-phone-reception
http://www.bleepingcomputer.com/forums/t/360217/no-good-cell-phone-reception-in-my-home/
http://www.openmutual.org/2012/03/foil-backed-insulation-blocking-wifi/
http://www.constructionknowledge.net/blog/?p=2087
http://www.telegraph.co.uk/technology/advice/8260686/Ask-Rick-wifi-reception-special.html
Just because the problem hasn’t affected you so far, doesn’t mean it doesn’t exist for others. T Mobile appears to have confirmed foil backed insulation “can sometimes act as reflectors to signals or can block signals so that they do not penetrate into the structure.”. The issue will likely depend on house structure, depth of insulation used, window gaps, original signal strength etc. I certainly couldn’t get 50mm of cellotex signed off by the Building inspector as cited in one example with no issues. In my area the BI wants 150mm combined from between rafters and on top of a foil backed cellotex type material. That is 4 layers of foil. Exactly the same amount my f-i-l has with limited phone reception. It’s possible we would be lucky and not see any issues – but why risk it if there might be alternatives?
xDave – is the product you mean this one? Thermaroof TR27 LPC/FM
There is alot of evidence of people with similar issues out there - try Googling for ‘foil backed insulation mobile reception’ & ‘foil backed insulation wifi’
http://www.pcpro.co.uk/blogs/2011/04/14/whats-killing-your-wi-fi-wrapping-your-house-in-tin-foil/
http://www.greenbuildingadvisor.com...-building-products-block-cell-phone-reception
http://www.bleepingcomputer.com/forums/t/360217/no-good-cell-phone-reception-in-my-home/
http://www.openmutual.org/2012/03/foil-backed-insulation-blocking-wifi/
http://www.constructionknowledge.net/blog/?p=2087
http://www.telegraph.co.uk/technology/advice/8260686/Ask-Rick-wifi-reception-special.html
Just because the problem hasn’t affected you so far, doesn’t mean it doesn’t exist for others. T Mobile appears to have confirmed foil backed insulation “can sometimes act as reflectors to signals or can block signals so that they do not penetrate into the structure.”. The issue will likely depend on house structure, depth of insulation used, window gaps, original signal strength etc. I certainly couldn’t get 50mm of cellotex signed off by the Building inspector as cited in one example with no issues. In my area the BI wants 150mm combined from between rafters and on top of a foil backed cellotex type material. That is 4 layers of foil. Exactly the same amount my f-i-l has with limited phone reception. It’s possible we would be lucky and not see any issues – but why risk it if there might be alternatives?
I've just wrapped my whole p.c. ensemble in foil and it still works!
Blimey.
Must be special foil on that celotex stuff.
I wonder if the military or NASA know about it........
Blimey.
Must be special foil on that celotex stuff.
I wonder if the military or NASA know about it........
No that's the headquarters of Google!
You mean Googolplex!
Yes yes, I've been Gogglein.
Oh yeahYou mean Googolplex!
Yes. You may still need to include a vapour barrier into your design.
Take the Celotex you've bought (you have loads of it lying around, right?), your laptop, your phone and..
..stand 4 sheets up around yourself corner to corner. A bit of duct tape on each should keep them from falling
Put a 5th sheet on top
You now have a very small, 100% celotex insulated house.
How are your mobile and wifi signals?
..stand 4 sheets up around yourself corner to corner. A bit of duct tape on each should keep them from falling
Put a 5th sheet on top
You now have a very small, 100% celotex insulated house.
How are your mobile and wifi signals?
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