Author Topic: Should I get floor insulation in my T/A?  (Read 478 times)

Maxthe222

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Should I get floor insulation in my T/A?
« on: November 02, 2019, 03:07:48 PM »
Honestly, I don't even really know what the point of it is. Is it just to keep the exterior noise down in the cabin of the vehicle? On a T-Top car I feel like that point may be moot. Someone told me it was also to keep heat in the car etc.

I have a black Y84 with the Camel Tan interior, and a black car in the Australian climate can turn the inside of the car into a portable BBQ. Since my interior is completely stripped right now and it will be for another few weeks while I wait for a dashboard to arrive, I am considering those silver-y metal floor mat things people put in their cars. My Y84 didn't come with the additional acoustical insulation option, but my F/A did and boy I wish it didn't looking at all the big thick tar slabs that were in it.

I feel like they trap a lot of moisture and water in the floors and I'm particularly interested in having it, but if it does considerably benefit the driving experience from reducing sound or whatever, I'm just not entirely sure what the benefits of having it in a T/A are, but I am open to suggestions and other ideas.
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula 400 4-Speed

aussieta

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Re: Should I get floor insulation in my T/A?
« Reply #1 on: November 02, 2019, 09:14:54 PM »
i chased an excessively hot exhaust system for years
to the extent that the carpet would smoulder
later found my distributor was not phased correctly
i had the factory soundproof insulation
i fitted the foil bitumen roll insulation
made a big difference to the sound in the cabin
and a small difference to the heat
wished i had done the headlining as well
1978 Y84 W72 WS6
A Camaro looks like it could kick your ass.
A Trans Am looks like it's coming over to do it

jonathonar89

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Re: Should I get floor insulation in my T/A?
« Reply #2 on: November 02, 2019, 11:57:40 PM »
I was always fine without insulation...

Grand73Am

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Re: Should I get floor insulation in my T/A?
« Reply #3 on: November 03, 2019, 08:46:13 AM »
It does reduce noise in the interior, and makes the car feel more solid. That's what the factory tar material did. I know the old tar stuff would get ugly over the years, and the floors sometimes rusted underneath it. But, the sheet metal floor, without insulation, transmits vibration and noise when left bare. Just imagine taking a piece of bare sheet metal and tapping it with a hammer. You know it's going to have a sharp, ringing noise. Now stick some insulation to it, and you'll get a quieter "thud" instead, since it deadens the vibration.

The type of insulation to use directly on the floor metal should be something that simulates that factory tar material. Nowadays, there are better materials than the tar. There are tar based insulations, like used for construction, but stay away from them, since tar can melt and make a mess when overly heated. And it can have an odor. Instead, the best floor insulations are made from butyl rubber, like Dynamat. There are other brands, but be sure they're butyl. Butyl doesn't melt or stink. Some people cover the entire floor with it, which is bound to make it super quiet. But, you don't have to cover everything to get the effect. If you cover most of the flat broad areas of the floor, that act like a metal drum, and stick a large square of butyl insulation in the middle of it, it will stop the drumming type of vibrations and noise. So, that kind of insulation is mostly for noise and vibration control. It will reduce some heat, but is mainly for the noise. It's the most important part of the floor insulation.

For heat reduction, an air barrier is used. When you buy carpet, it normally comes with a "jute" backing. This jute backing is a good heat insulator since it holds air in the fibers, and may be all you need, and you'd be done. If you want additional heat reduction, you could install some of that bubble wrap covered with silver foil over your butyl floor insulation, before installing the jute backed carpet. There are other products besides the bubble wrap for heat insulation too, like fiber or foam material, stuff that holds air. 

I even like to stick some Dynamat to the inner surface of my door metal, underneath the door upholstery panel. They make some Dynamat that's thinner for doors. I use it in place of the paper water shield that the doors originally came with. Makes the doors sound quieter and more solid.

The floor won't rust if you prepare and paint it with good materials. While your interior is out, it's the perfect time of course. Strip the old paint and rust off your floor, and make sure it's clean. Then there are a couple of materials that are good. I've used both. My favorite is to paint it with two-part epoxy primer. This is real automotive primer that you'd buy from an auto body paint supply store, not spray cans. Spray it with a gun. Then spray some single stage urethane paint in your choice of color over the epoxy. Even clear urethane would be good. Or instead of epoxy, POR-15 over a properly prepared surface works good too. Follow the instructions for proper preparation of the metal for using it, so it will stick. It can be brushed on. Then use urethane paint over it too. Either of those would protect the floors better than what the factory paint did.
« Last Edit: November 03, 2019, 08:53:29 AM by Grand73Am »
Steve F.

roadking77

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Re: Should I get floor insulation in my T/A?
« Reply #4 on: November 03, 2019, 10:50:46 AM »
YES.  I was trying to stay as close to factory correct on my 77. I installed the factory type insulation (looks like really heavy tar paper). I can only assume it works because my car is so loud. I cant imagine if I did nothing. On my current project that is one area I plan improving on.  So with my experience I would say put the best and most that you can afford.
Finished!
77 T/A - I will Call this one DONE!
79 TATA 4sp-Next Project?
79 TATA - Lost to Fire!
86 Grand Prix - Sold
85 T/A - Sold
85 Fiero - Sold
82 Firebird - Sold
'38-CZ 250
'39-BSA Gold Star
'49-Triumph 350
'52-Ariel Red Hunter
'66-BSA Lightning
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Re: Should I get floor insulation in my T/A?
« Reply #4 on: November 03, 2019, 10:50:46 AM »

Maxthe222

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Re: Should I get floor insulation in my T/A?
« Reply #5 on: November 03, 2019, 02:51:59 PM »
Oh wow lol I thought it was like a scam or something, I didn't know it actually worked that well lol. Yeah everyone says dynamat, but don't know how expensive that is to source down here. But, definitely something I will have to look into. Painting the floors again may be a good idea, I think they've already been repainted with another layer of black, if I do rub the floor back, just with some sandpaper or something? I've dabbed some rust converter over some small spots not sure if that'd be enough. I'll look into the mats in that case, sounds like it can't hurt!
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula 400 4-Speed

FormTA

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Re: Should I get floor insulation in my T/A?
« Reply #6 on: November 03, 2019, 03:51:57 PM »
I've heard it's quite a difference.  I bought the Dynamat copy and plan to use the factory stuff too. My wife had a Lexus and that thing was super quiet inside. That's my goal... We"ll see...
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

Names, Luke. If I hear anyone telling me they're my father....

Grand73Am

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Re: Should I get floor insulation in my T/A?
« Reply #7 on: November 03, 2019, 04:13:27 PM »
if I do rub the floor back, just with some sandpaper or something? I've dabbed some rust converter over some small spots not sure if that'd be enough.

I don't believe in rust converter. I've seen it fail. The best way is removing the rust completely, like by sandblasting the metal clean. Then after blowing and vacuuming all the sand out, using the epoxy primer would be preferable. But I understand that if you haven't completely taken the car apart, sandblasting would be messy and might damage things like the glass and get into the dash, etc. if you don't mask them off thoroughly. Even if you don't completely disassemble the car, with enough plastic sheeting and duct tape, you could mask of the doors, ceiling, dash, and glass sufficiently and still be able to carefully sandblast the floor.

Or without taking the car all apart, and not having to mask off as much, the 2nd best course of action would be to use a rotary disc sander and sand the floor down as good as you can, making sure to sand off all loose rust. After sanding, you can use a wire cup brush on a drill or grinder, and wire brush the rust to get down in the pits as best you can. Then you can use the POR-15 procedure, since Painting Over Rust (POR) is what it's best for. It's something that actually does work and seals the "tight" rust that you just can't completely sand off. So, it's good for when you can't remove all the rust. A word of caution. When sanding or grinding, make sure you cover the glass on the inside. Any grit or sparks thrown up by the sanding or grinding will make pits in your glass if it hits it.
Steve F.

Grand73Am

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Re: Should I get floor insulation in my T/A?
« Reply #8 on: November 03, 2019, 04:34:14 PM »
Of course, you don't have to buy Dynamat. It's pretty expensive. I was reluctant to buy some because of the cost. But, I gotta say that it's really good, high quality stuff. So, I was happy with the purchase. But there may be others just as good or close to it, for less. Just make sure it's the butyl rubber type, and not the tar type. Do a search for butyl floor insulation an you'll find different brands.
Steve F.

Grand73Am

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Re: Should I get floor insulation in my T/A?
« Reply #9 on: November 03, 2019, 05:00:41 PM »
I just remembered a 3rd method for stripping the floor for painting. If you don't have much rust, you could sand the floor with the sander, but use a spot blaster for just the rusty spots. That wouldn't make as much mess as a full sandblasting, and you could remove all the rust.
Steve F.

cyber104

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Re: Should I get floor insulation in my T/A?
« Reply #10 on: November 05, 2019, 08:21:19 AM »
I just used the mass backed carpet and called it a day - worked well for me and I'm running dual exhausts (1 muffler per leg) and an "H" pipe.

I don't like sticking things to the floor - too much trouble to get off and water can get trapped underneath.

I'm sure there are products that cut down noise and heat - but I didn't feel it necessary.

Chris
1978 TA 4-Speed W72

Maxthe222

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Re: Should I get floor insulation in my T/A?
« Reply #11 on: November 05, 2019, 03:04:24 PM »
Actually, just spoke to some mates down here about it, is it a bad idea due to it being a T-Top car? I do often drive the car in the rain and wet, and I am scared it will hold moisture under the floors, is that something to consider? And G/A lol if I had access to any of that stuff right now my F/A would be done already lol, but the most I have is a wire brush, sandpaper, rust converter, kill rust paint and etc. I don't know enough about POR except that's what everyone suggests to use, but I don't think I'd properly be able to use it
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula 400 4-Speed

Grand73Am

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Re: Should I get floor insulation in my T/A?
« Reply #12 on: November 06, 2019, 12:25:46 AM »
Actually, just spoke to some mates down here about it, is it a bad idea due to it being a T-Top car? I do often drive the car in the rain and wet, and I am scared it will hold moisture under the floors, is that something to consider? And G/A lol if I had access to any of that stuff right now my F/A would be done already lol, but the most I have is a wire brush, sandpaper, rust converter, kill rust paint and etc. I don't know enough about POR except that's what everyone suggests to use, but I don't think I'd properly be able to use it

If you strip, clean and paint the floor using one of the methods I wrote about, you wouldn't have to worry about it rusting, even if some moisture got on it, because the paint materials are waterproof. I doubt you'll be leaking so much that you have puddles and your carpet is soaked. If that happens, you'll have a problem either way. I have a 79 with t-tops and it doesn't leak, unless it's raining heavy, and then I just get little drip on my left leg. I carry a towel for that :) . Using POR-15 is about the simplest thing to do, and doesn't require special equipment. You can brush it on with a brush, and it levels out pretty nicely on its own. Just follow the instructions on preparation and application.

And believe me, those rust "converters" are worthless. Please don't use them.
« Last Edit: November 06, 2019, 12:27:20 AM by Grand73Am »
Steve F.

Maxthe222

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Re: Should I get floor insulation in my T/A?
« Reply #13 on: November 06, 2019, 02:16:39 AM »
G/A don't worry I completely believe you, but it's as simple as I won't have the money to do my Y84 floors to that level, I've gotta just get this car's interior done to a high standard with what i've got, and focus the majority of the funds on the Fire Am. Look, the car has been restored before I got it, and if there is one thing I can say about it the paint is really really good on the outside. The floor looks like it has absolutely been repainted. In the time of my ownership though, I had parked it outside in the rain for a few months and a lot of water did build up on passenger side floor. Everywhere else is very dry and clean. I looked into the POR-15 stuff, I thought it had like 4 different things you needed to do before you applied it, seems just like a brush on thing and I think i'll just that stuff to cover up the area around the passenger kick panel opening when I try to seal that thing up water-tight, I've been looking at that guide explaining that I should make a sort of roof over the kick hole. My T-Tops do not leak, but the kick panel hole leaked heavily and you could feel and see it in the carpet. As for the rust converter, I didn't just slap it on top of the rust, I did heavily sandpaper and wire brush the affected areas and brushed it on top. I've been told good things about it, and the only reason why I used it was because it was so cheap. I did that a month or so back, and it looks like it held up reasonably well. It was this stuff that went on like a chocolate milk colour, and then dried over the course of a few days. I think you are supposed to paint on top of it as well, but I haven't got hold of that kill-rust paint yet, which I think is a form of epoxy primer. Maybe i'll just coat it in POR-15? I did notice there is this tiny pin hole on both my cars in the corner of the driver and passenger side window pillar near the top back, could be how water got in. I'll upload pics to explain maybe later. I also do have the new "jute" thicker carpet in the car.... I think. The heat from underneath wasn't really an issue, the cowl area did have some unfilled holes that did let a lot of heat from the engine straight in, but I will plug those up correctly with what was missing from there. I'll look around for people with the sound insulation in their car, this is a totally stock 403 after all, so I don't even know if it really even makes that much noise compared to one with it installed.
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula 400 4-Speed

Grand73Am

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Re: Should I get floor insulation in my T/A?
« Reply #14 on: November 06, 2019, 07:11:35 AM »
True about the kick panels. I've also read the old posts about making a shield over the openings. Can't hurt. I didn't do it though. I just used plenty of black caulk, like the factory did. I used 3M 08578 black strip caulk.

And don't use POR-15 over the other paint. It's supposed to be used directly on the metal, or rusted metal.
Steve F.

Re: Should I get floor insulation in my T/A?
« Reply #14 on: November 06, 2019, 07:11:35 AM »



rkellerjr

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Re: Should I get floor insulation in my T/A?
« Reply #15 on: November 07, 2019, 09:02:02 PM »
I didn't have any when I bought my car, it was noisy and HOT in Virginia's 90 degree summers. When we replaced the floor boards I put down Eastwoods version of Dynomat, up the firewall, throughout the floor and up the back. What a difference, quiet and I no longer roast in the summer of the heat of the car. From my perspective, well worth the cost and time to install.

TA1754

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Re: Should I get floor insulation in my T/A?
« Reply #16 on: December 04, 2019, 12:48:06 PM »
YES.  I was trying to stay as close to factory correct on my 77. I installed the factory type insulation (looks like really heavy tar paper). I can only assume it works because my car is so loud. I cant imagine if I did nothing. On my current project that is one area I plan improving on.  So with my experience I would say put the best and most that you can afford.

My floor is all stripped down, & ready to do the POR-15, I have also purchased the factory type jute underlayment, same as what was originally in there.
I plan on installing dynomat on the back wall where the rear seats go, & front dash area, but would it be overkill to put it on the floor before the jute pad?
« Last Edit: December 04, 2019, 01:04:53 PM by TA1754 »

FormTA

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Re: Should I get floor insulation in my T/A?
« Reply #17 on: December 04, 2019, 03:20:34 PM »
I don't think so. That is my plan too.
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

Names, Luke. If I hear anyone telling me they're my father....

roadking77

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Re: Should I get floor insulation in my T/A?
« Reply #18 on: December 04, 2019, 03:35:44 PM »
What you are planning is exactly as I did. I got some thick dynamat, maybe 1/2"-3/4", put it on the divider behind the back seat, put it on the inside wheel wells. I used the 'tar paper' factory matting, with the jute backed carpet. Like I said before, it is loud!! I def would put something additional on the floor if I were you.
Finished!
77 T/A - I will Call this one DONE!
79 TATA 4sp-Next Project?
79 TATA - Lost to Fire!
86 Grand Prix - Sold
85 T/A - Sold
85 Fiero - Sold
82 Firebird - Sold
'38-CZ 250
'39-BSA Gold Star
'49-Triumph 350
'52-Ariel Red Hunter
'66-BSA Lightning
'01-HD RoadKing

Re: Should I get floor insulation in my T/A?
« Reply #18 on: December 04, 2019, 03:35:44 PM »
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