What to use under carpeting?

[65Fury440]

I was looking for the lightest thing possible.
Home Depot had some double bubble foil faced stuff. It was super easy to work with, used spray adhesive to fasten it down, worked great.
https://www.homedepot.com/p/Reach-B...Air-Roll-with-Double-Bubble-DD48050/204476657

 

[Dibbons]

I used Rust-Oleum rusty metal primer under Thermo-Tec foil/butyl insulation. Then on top I used a foam Dynaliner product. In the trunk, i used Monstaliner, a pickup truck two-part bed liner. The factory carpet had a very thick matting type insulation, so I did not want to end up with anything inferior to that.

Oddly enough, while driving in my vehicle (no A/C) during a super-heat wave (over 100 degrees) on the freeway, I found it was cooler to drive with my windows closed.

 

[idrivemopar]

I did dynamat, got it when it was on sale! Only did the floor and front part of the rear wheel wells, the rest of the car was done with stock insulation, shoddy pad, etc.

 

[themechanic]

The foil backed adhesive sheets like Dynamat, Fat Mat etc. don't do much for heat prevention. They do what they are designed for and interfere with the propagation of sound and vibrations through the sheet metal.

The floor in my Coronet has Fat Mat and the El Camino has Dynamat but the floor still gets hot above the exhaust headers without adding an extra layer of material specifically designed as a heat barrier. The El Camino has mass backed carpet. It's fairly heavy but the cab is quiet.

The Coronet has Fat Mat for sound deadening and Bonded Logic's Tru-Max doubled sided foil heat insulator mat with the recycled denim insulation between the foil.

On a side note: The windshield leaked and the foil backed heat barrier was soaked and held the water so long the carpet molded and the seat brackets rusted. The car was at a paint shop during a heat wave while this happened and never dried out until I removed the carpet and Tru-Max. I got the windshield leak fixed and plan to use regular carpet and the Tru-Max. One thing I can say about the sound deadener is it saved my floor from rusting when the water soaked the carpet and Tru-Max.

There are recommendations based on the daily temps where you will be driving to consider. So, check with each manufacturer before you buy.

By the way, you can order your carpet without the jute glued to it. I did this after having trouble with wrinkles caused by the jute bunching up in the mold when the carpet was formed. The Tru-Max is about the same thickness as the jute. So, if you go that route you can use the jute as a pattern for cutting the Tru-Max unless you prefer to cover the entire floor.

 

[Evan Frucht]

I was looking for the lightest thing possible.
Home Depot had some double bubble foil faced stuff. It was super easy to work with, used spray adhesive to fasten it down, worked great.
https://www.homedepot.com/p/Reach-B...Air-Roll-with-Double-Bubble-DD48050/204476657

wouldn't that flatten out over time with people getting in and out of the car? even immediately

 

[65Fury440]

wouldn't that flatten out over time with people getting in and out of the car? even immediately

No, it actually held up really well. It did flatten out under the seat frame and where the back seat bottom sits. The rest still looks new after 3 years.
I have used the tar based deadener in the past, I feel the R rating of this stuff is much better, keeps heat out very well.
If there;s any down side, I would guess it doesn't muffle sound as well, but it quieted my car down tons, although the carpeting surely helps too,

 

[pushrod]

I found that the windshield reflector made of aluminum and insulation work great.for heat barrier especially on the trans tunnel. Flexible and easy to cut to size with sicisors.

 

[Xp29h]

I used similar stuff from Home Depot. Heat duct insulation. The rolls came a little smaller than what 65 showed but these had adhesive back. Worked great. After interior install and car has been on the road for a year or so since and no issues. Don’t feel the heat as I used to and the vibrations and “open” feeling is gone. Worked great.

 

[Runner 68]

I used similar stuff from Home Depot. Heat duct insulation. The rolls came a little smaller than what 65 showed but these had adhesive back. Worked great. After interior install and car has been on the road for a year or so since and no issues. Don’t feel the heat as I used to and the vibrations and “open” feeling is gone. Worked great.

Yep, we did too. 6" wide rolls to get into the tight spots rather than cut a sheet of kill mat plus the stuff at home depot is very cost effective. Same stuff.

 

[themechanic]