# Should I Mat the roof?



## Sethticlees (May 30, 2002)

I'm considering sound deadening the roof since i got the headliner off and waiting for replacement parts. 

So I have a bunch of leftover FatMat and I'm willing to use it but I'm hesitant. See FatMat along with other mat products gets really sticky when its hot but during the cold months it can get brittle and hard. 
Combine brittle and hard along with gravity and a vibrating car... this could be not good.

What do the gurus think?

I may get away with it but for how long 3,4,5 years maybe... or less.

The other alternative is spray. I got some VB-1 spray I could do instead, but something I don't like about the VB-1 is the grit. The surface looks smooth when applied but once VB-1 dries you'll see and feel the grittyness. 
No prob you say, it'll all be covered by the headliner. Well, like most gritty surfaces the grit tends to loose its contact and well, sand... sand everywhere.

VB-1 can be painted, sanded, or both (works great) but that can turn into an ugly job. Especially with the sunroof internals in my way and upside down and, No, No, No!

So suggestions? 

Thanks
Seth


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## sr20dem0n (Mar 19, 2003)

I'm not sure how long it would last really. I did my roof in Fatmat a while ago and for all I know it could all by sitting on top of the roof liner now, haha. Fatmat wasn't exactly the stickiest stuff I've ever seen, so I would really be hesitant to put it on the roof where there are such drastic temperature changes and gravity constantly working against it. It really doesn't help all that much either, you get rid of a little wind noise, and it's much quieter when it rains, but engine and exhaust noise resonate so much more. My exhaust got close to twice as loud when I matted the roof, then when I matted under the rear seat it went back to how it was before. Honestly I would just do the floor, under the rear seat, and the trunk with it. If you've done them already then do a 2nd or 3rd layer, it will have a much greater effect than the roof will IMO.


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## Chicago Tony (Apr 15, 2003)

What kind of system are you running that you are planning to deaden the roof?










Sethticlees said:


> I'm considering sound deadening the roof since i got the headliner off and waiting for replacement parts.
> 
> So I have a bunch of leftover FatMat and I'm willing to use it but I'm hesitant. See FatMat along with other mat products gets really sticky when its hot but during the cold months it can get brittle and hard.
> Combine brittle and hard along with gravity and a vibrating car... this could be not good.
> ...


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## Captain Obvious (Jan 2, 2004)

Every where I have looked I was told they only suggest that you deaden the floor,trunk and half way up the doors. I have done the whole doors never done the roof though.
Cant you get a thin layer of felt or simaler material and put that on the bare metal first with 3m spray carpet adhesive then mat then headliner.
That may insulate it a little bit but then again like I said I dont know cause it will get brittle in cold and gooey in heat like you said.
you can always just double up the floorboard around where the tranny is and in back then get a spray deadner for the roof.


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## wes (Apr 30, 2002)

Do it but use a quality material. I used a roll of Dynamat premium on my roof over 4 yars ago and it sill looks the same as when I put it on there. I also purchased the densest polyfoam padding I cuold find froma carpet store and spray glued that on the cardboard backing of the roof liner. Worked great!


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## Sethticlees (May 30, 2002)

wes said:


> Do it but use a quality material. I used a roll of Dynamat premium on my roof over 4 yars ago and it sill looks the same as when I put it on there. I also purchased the densest polyfoam padding I cuold find froma carpet store and spray glued that on the cardboard backing of the roof liner. Worked great!


I like that padding idea best. 
It's much much easier to pad a headliner than it would be to mat the entire roof.

Great idea guys!

Thanks


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## wes (Apr 30, 2002)

Sethticlees said:


> I like that padding idea best.
> It's much much easier to pad a headliner than it would be to mat the entire roof.
> 
> Great idea guys!
> ...


I also applied the padding to the back side of all the plastic interior parts and under the carpet as well. VERY cheap and worked great.


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## OldOneEye (Oct 22, 2002)

I am in the process of doing under the head liner with Dynamat Extreme. Since I have a sunroof, I can't fit some sort of mat or foam. If you can, I would get some foam (something like a hoodliner or tacmat) and attach it under the headliner. The roof of your car is the biggest continous panel on the car that isn't reinforced (the hood is reinforced as is most of the sheet metal you see in the car) so it definately helps. I did it in my wifes car and noticed a big difference. You can add more power (which adds weight) or you can add quiet to your car (which adds weight as well) or you can do both. It is probably the worse place you can add weight to a car (raises the center of gravity) but it doesn't take much to make a big difference (and a sunroof assembly weighs so much more than the amount of sounddeadener you would add).

Seth, I just noticed you are local (and have a sunroof). I can send you pictures of mine if you want, give you an idea what I've done. Drop me a PM. 

Juan


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## sr20dem0n (Mar 19, 2003)

studeringaaron said:


> Every where I have looked I was told they only suggest that you deaden the floor,trunk and half way up the doors. I have done the whole doors never done the roof though.
> Cant you get a thin layer of felt or simaler material and put that on the bare metal first with 3m spray carpet adhesive then mat then headliner.
> That may insulate it a little bit but then again like I said I dont know cause it will get brittle in cold and gooey in heat like you said.
> you can always just double up the floorboard around where the tranny is and in back then get a spray deadner for the roof.



Matting a layer of felt would be useless. Mat is a mass loader, it deadens by adding mass to a panel to keep it from oscillating with the bass and absorbing sonic energy. If you isolate the panel from the mat by putting a layer of felt in there, you just killed all effect the mat has.

Do you want to get rid of road noise or keep in bass? If you want to keep out road/wind noise then get some closed cell foam and put a couple of loose layers in between the roof and the headliner. This will absorb ambient noise and keep it quieter inside. If you want to keep in bass by reducing the vibrations, then you HAVE to mat the roof, there's no other way around it (other than liquid deadeners, but you run into the same problems with that). Foam, padding, etc won't do a single thing for keeping in bass, and depending on what you use it might not keep out road noise either.


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## Russia (Jul 24, 2003)

While we're talking bout matting roofs, after watching that vid with the pennies bouncing all over the roof with the bass turned up I was like damn I wonder if thats true, so I blast my system and put a plastic iced tea bottle on my roof...holy shit, that thing was knocked off and thrown around in a second...its crazy how much the roof flexes.


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## Solidox2k (Jan 21, 2004)

so long as this topic's up, i recently took the ceiling panel off (seems there's 4 slots in the rear panel, that match with slots in the metal roof, but nothing was securing it????) neway, i got curious and added some carpet foam inbetween the crossmembers of the roof w/adhevsive, since i couldn't really tell where they would mount on the ceiling panel itself.... i was wondering if it could help vibration and insulation.....

it *has* kept the sound in the car sounding a bit better....its a little less road and roof noise. i haven't really noticed any insulation differences.

the foam keeps it from rattling (that w/foam tape on the x-members themselves), but i think some sort of loose stuffing would've worked better for the sound (just what i think, i really have no clue).

BTW: what is that fiberglass like green stuff on the back of the sidepanels, stock?


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