Hmm, I haven't tried the roofers' tape. But I like the ease of use of pre-fabricated damping material. You simply cut it to measure, it will fit cleanly, and come off if you need to re-position. The glue suggestions sound messy to me - but that's just me not being able to work cleanly.
In Europe it is reasonably easy to find BeQuiet!
damping kits, which are much less expensive than AcoustiPack --- I don't know about the availability in Canada.
I have used both the AcoustiPack stuff (Sonata kit) and the BeQuiet! stuff (big tower kit), and they handle similarly. AcoustiPack has a very slight edge if you want to reposition it, it sticks securely but comes off rather painlessly if you want. The BeQuiet! barrier mass deforms somewhat if you want to tear it off --- it does come off without major damage though (unlike the foam only peace that's also in the BeQuiet! kit and whose adhesive film is extremely difficult to remove once stuck to a surface).
The BeQuiet! barrier mass (they call it bituminous board) is thicker and stiffer than the AcoustiPack, but a touch lighter (per surface). The foam is also thicker and stiffer and has this honeycomb pattern on the surface. The foam is open cell, but from trying to breath through it seems more "closed" than the AcoustiPack (maybe due to the pattern which seems to be simply pressed in shape from a foam of uniform thickness). All of the materials are pretty "dead" sounding/feeling alright. I don't know how to compare them in terms of sound proofing cabability, since what I did was first fitting both of my Sonatas with the AcoustiPack, and recently adding the BeQuiet! stuff to places left uncovered before, and to cover ducts/mods...
So the only comparison I can do is look at the amount of material I get for my money:
BeQuitet!, big tower kit:
5 sheets, 40x24 cm^2, 2.2mm barrier mass, 8mm foam, approx 4.4 kg/m^2
1 sheet, 40x24 cm^2, 20mm foam only
30 EUR ~ $48 CAD, ~ 23 $CAD/kg, 100 $CAD/m^2
AcoustiPack, Deluxe kit:
2 sheets, 49.5x39.5 cm^2, 2mm barrier mass, 5mm foam, approx 4.6 kg/m^2
1 sheet, 49.5x39.5 cm^2, 2mm barrier mass, 15mm foam, assumed 5 kg/m^2
couple of foam blocks to tuck here and there (useful to channel airflow)
$115 CAD, ~ 41 $CAD/kg, ~ 196 $CAD/m^2
(I haven't used it and don't know how much it weighs)
3 sheets, 40x50 cm^2, 1.5mm barrier mass, 6mm foam
45 EUR ~ $72 CAD, 120 $CAD/m^2
Roofers tape and eggcrate foam:
(see Tibors' posts)
eggcrate foam, 50x100 cm^2, 30mm thick, 9.75 EUR
1 roll of roofers tape, sufficient for one sheet of foam, ~15 EUR
24.75 EUR ~ 40 CAD, 80 $CAD/m^2
Tibors: You mentioned a sticky side and one with aluminum foil. Is this the stuff that looks like a mix of tar and rubber and can also be used to seal plumbing? I have seen tape like this before, it was impossible to remove from anything it touched...
Does anybody know how much the Nexus DampTek weighs?
I'm interested in these comparisons, because I'll likely need more of this stuff. I'm developing a Bluefront-like obsession to cover everything
with it, and seal even the tiniest cracks (no offense intended. It's me who's obsessed).
EDIT: added price info about roofers tape/ eggcrate foam from Tibors
' post below