Roof radiant barrier - double benefits?

I'm looking to install a radiant roof barrier to help the energy efficiency of my house, but I'm also wondering how good it will work to block RF coming in through my roof.
It's mostly made of aluminium foil. I think it should be pretty good.
Anyone tried it?
It looks flexible enough that it can be woven in between two layers of cotton and used as EMF blocking fabric as well, at a fraction of the price.
Any thoughts?

http://www.ebay.ca/itm/1000sqft-Radiant-Barrier-Solar-Attic-Foil-Reflective-Solid-Insulation-4x250/331407703803?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140620091118%26meid%3Df7936971ecf34f1983b0fda3feaef02a%26pid%3D100005%26rk%3D4%26rkt%3D4%26mehot%3Dpp%26sd%3D371802746682

They sell something of the like at lessemf.com.  I use a space blanket behind a beautiful door curtain to keep the heat in and cold out and reverse in the summer. Does nothing for emfs, due to the fact it is coming thru the unshielded roof and other windows not shielded. I am thinking of trying and experiment soon where I cover the ceiling in cheap space blankets and see what readings I get. After I put shielding curtains over the other windows.  I have not done much on this as I think it not really possible to truely shield an RV to begin w/ and better spending any $$ to get out of debt from moving here so I can move to a better spot. Sorry that is all I know.