The Beauty of Ham radio is experimentation and discovery.
You might just want to do a temporary experimental setup of your antenna in the Attic, and see how it goes... The interactions/reflections of your foil/HVAC/wiring in general, and your individual appliances, walwarts, etc. (And neighbourhoood) may or may NOT cause you problems.
Of Course, there may be some attenuation, as K1VSK says. But it may be insignificant. And highly individual to your QTH. But I'd try that before I started ripping off foil from the insulation, if it were me. Same for UHF/VHF... I'd try the antenna, First. You might be surprised!
Off the cuff, and with no data sheets? My guess is that at HF, less of a problem. And as you move up the scale to 900 MHz? More so. But I can't say how much more so, or less so.
I'm certain that everyone with a cell phone has noticed the Faraday Caging that happens when you get in an elevator and the doors close.
As far as HF recieve, my experience is that on HF SW listening, a lot of the rules don't apply.
My teenage pal Billy Lyons and I had the pleasure of having an old Grundig in his parents basement cave/bar that his Dad brought back from when he was a soldier in Germany. (One of his jobs was to drive Elvis Presley around in a Jeep to his publicity interviews, featuring Elvis in his combat fatigues!)
So anyway, we just ran a wire for our antenna around the ceiling rafters of the basement. And that worked pretty well. We didn't know why at the time, but it worked! Now many years and engineering texts later, I realise that the issue wasn't Signal Strength, it was that we overcame Signal to Noise with that modest setup.
Many an evening of SWL enjoyment was spent there, listening to that Beautiful Grundig post war blonde wooden set, and Wow the speakers sounded really good. There being a bar located there complete with liquor bottles that his parents always marked on the side with a Sharpie marker so they could "tell" if any was removed, we Of Course thoughtfully used our own "Sharpie" to remark the bottles. And we never got into any Juvenile "Trouble" whatsoever...
So, experiment! You may find that your set works great in Spite of the complely draconian and arbitrary rules imposed by the HOA Jack Boots!
Let us know how it works out!
I'd love to try a QSO with you sometime with your new setup!
I also propose a new Contest/Special Event for those in HOA Occupied Territories to work other ops who are also "living" in other HOAs, all out there making contacts right under the Nose and Belly of the HOA Monster.
The "Nelson Cup" will be an Inspiration for those living in places like North Korea and other HOAs in places like Florida to Get On The Air in Spite of it all!
73 DE W8LV BILL