I am doing a winter interior project on the 172 including pulling out old wiring (up over 20lbs so far!), painting panels, new seats, etc. I have been considering going with Selkirk's insulation kit for the sides and ceiling. They offer both 1/4" as well as 1/2" foam. The 1/2" weighs about 9lbs for the the total kit with the 1/4" about half of that. Has anyone used one of the Selkirk kits? I understand it still needs a spray adhesive to mount the insulation. Is the 1/2" worth the the extra weight or is 1/4" adequate. I am a little limited on time so I like the precut nature vs the roll your own approach. I'm open to other suggestions as well. I figured now is the time to tackle it while the interior is all out.

I’ve used their insulation kits a few times and have been happy with the results. On 1/4” vs 1/2”, since the only tangible benefit is noise reduction and not heat loss, my best guess is that you would get 90% of the benefit out of 1/4” and would just lose 4 pounds of useable load with the 1/2”. That’s definitely a WAG calculation though.
FWIW, I love their interior kits too, but the fiberglass does seem to be noisier than fabric.

I have used there kits on two planes. I like the product. I have used 1/4" everywhere. and 1/2" in the extended baggage for protection as I have no sides in there. I like the 3M contact adhesive more than the super 77. especially on the ceilings. It seems to hold better.

When working under the instrument panel and on the firewall I use a sound proofing product from airtex: it is 1/4" foil faced with adhesive already on one side. It really cleans up the look under there.

Thanks, appreciate the feedback. I was leaning towards the 1/4" insulation and sounds like that's the way to go.

We completely stripped out the cabin from extended baggage to panel. 1/4 is not thick enough to give much protection, it is ok if you put interior panels back in. but if not I would do the entire interior with 1/2. It fits better and does not stretch as you glue it into place. We cut our own it was not that hard glued in with 3M contact cement. DENNY

I ordered the 1/4" kit from Selkirk. They were good to deal with and it was pretty much spot on what I was looking or. The pieces are roughly cut to shape but require quite a bit of fitting still. In hindsight I would probably purchase the bulk material and do it myself. It would only be marginally more work and a little better outcome. It will be under my redone panels so It should work well regardless.