Later this month, I am replacing the cedar siding on my home with vinyl siding, fanfold insulation, and a vapor barrier. The fanfold is Alside Platinum Series AF38 Underlayment which is not foil backed. The contractor left me a sheet of the fanfold so I could test for attenuation and I am happy to say that there is none.
I am expecting improved reception as removal of my peak vents will eliminate a couple square feet of steel mesh from my line of site and vinyl should shed water better than cedar.
By the way, that 100% VHF signal is from WMTW whose antenna is 67.6 miles from mine!