Under-carpet Insulation?

marty085 · Postby **marty085** » Tue Aug 26, 2014 10:31 pm

So my NA filled with water (cabin and boot) due to there being no rain rail installed by previous owner.. thanks mate.

Pulled out all the carpets, it's all nearly dry now. A fair bit of the original under-carpet insulation material is in poor condition and now is a good time to replace it.

Advice needed:
1. What sorta shop can I get the same stuff from?
2. Are there any alternatives which provide the same level of noise and heat insulation but are lighter?
3. Should I just leave it out? Will noise/heat be that bad?

lizard · Postby **lizard** » Tue Aug 26, 2014 10:34 pm

http://www.dynamat.com/

Should be able to get it a little cheaper on ebay

Mr Morlock · Postby **Mr Morlock** » Tue Aug 26, 2014 10:46 pm

Automotive paint shops ie selling products will have some options.

lizard · Postby **lizard** » Tue Aug 26, 2014 11:14 pm

- Edit Okibi, forum etiquette 101, please don't quote the post directly above your own -

It also holds water and would be the best thing ever to promote rust :wink:

Snowmotion · Postby **Snowmotion** » Tue Aug 26, 2014 11:35 pm

These guys have all sorts of products for cars.
I got a roll of felt underlay that I used to insulate a van.

http://www.nolanuda.com.au/

Mr Morlock · Postby **Mr Morlock** » Thu Aug 28, 2014 8:14 pm

you use the right product - felt is not a good idea at all. Its a car not a carpet at home. Go to auto body people and get the right advice. You can also have spray on or paint sound deadener as well- been used for decades. Whether you want to use it is another thing.

Snowmotion · Postby **Snowmotion** » Thu Aug 28, 2014 8:32 pm

- Edit Okibi, forum etiquette 101, please don't quote the post directly above your own -

Mr Mortlock... you should not jump to conclusions. Nolanuda supply Automotive underlay which is what I have used and still use.

Mr Morlock · Postby **Mr Morlock** » Thu Aug 28, 2014 10:01 pm

My point is that cars and eSpecially open top cars don't use felt underlays because they absorb water. Rust in floors thru wet underplays is something to avoid. There are a number of treatments for soundproofing and insulation that don't wick like felt or some other more traditional carpet underlays. Dynamat is one well known but there are others. I bought a sticky back insulation recently for a footwell and it's sold by the piece. I think the maker was bostik but maybe wrong however I buy automotive body items from an auto paint supplier and that runs to a wide range of body products though.

A bloke I was chatting to recently found rust in chassis rails ie a rwc guy examined the vehicle with a camera. The rust is hard to detect if people use spray on body insulation.

Nolan UDA is a supplier to automotive for example headlinings and slow motion may have a good product.

Mr Morlock · Postby **Mr Morlock** » Thu Aug 28, 2014 10:03 pm

Correction read snowmotion

marty085 · Postby **marty085** » Fri Aug 29, 2014 4:07 pm

A place at revesby reckons that 10mm thick PE (polyethylene) foam will be good - closed cell doesn't hold water, and is decent for acoustic and thermal insulation.

Any reason why I shouldn't get some of this stuff?

Mr Morlock · Postby **Mr Morlock** » Fri Aug 29, 2014 5:17 pm

Closed cell materials should be fine. Clarks carry a range of foams. There is an easy test for open compared to closed cell materials. 10mm is pretty thick.

zephyrus17 · Postby **zephyrus17** » Fri Aug 29, 2014 9:20 pm

I installed Dynamat everywhere except for the extreme front leg space, and the firewall area. Didn't make a bit of difference, personally. Especially with a aftermarket exhaust, CAI, and driving with the roof down all the time...

marty085 · Postby **marty085** » Fri Aug 29, 2014 9:48 pm

Mr Morlock wrote:Closed cell materials should be fine. Clarks carry a range of foams. There is an easy test for open compared to closed cell materials. 10mm is pretty thick.

Do you reckon 6mm would be better? I can get some of that at Department of the Interior tomorrow, but I actually thought that would be too thin...

Garry · Postby **Garry** » Sat Aug 30, 2014 9:38 pm

I'd go the 10mm or even 2 layers of the 6mm. I'm using the stock stuff plus some aftermarket stuff plus some dynamat equivalent and everything fits OK. Though if you go to thick on the rear parcel tray and you have a hardtop the soft top wont fit under the stays on the hardtop as I found out.

As for dynamat, I found that it did nothing to stop the volume of the noise. What it did do was make the car feel more solid. If it hits a bump it makes more of a thud noise now rather than a twang like it used to.

I've tried lots of different underlay products and the stuff I'm using now was far and away better than anything else. Unfortunately I don't know the brand or where to get it. The roll I got came from Autobarn in Canberra many years ago and I've never seen it anywhere since. And I've been looking everywhere because I need some more for the rear bulkhead. It's a pinkish jute (I think that's what it's called) sort of product similar to the stock stuff but more dense, about 10mm thick and covered on one side with a thin metallic film.

With the hard top on, the dynamat and underlay installed my car is as quiet as a fixed roof car of similar vintage. It's still noisy with the soft top though.