How to Install Carpet over Dynamat.

[tonyci]

Hello All
About to install Dynamat to the rear of the 110. I then want to lay some marine carpet over the Dynamat. How should I secure the carpet to the Dynamat ?, will self adhesive velcro be ok stuck onto the back of the Dynamat. Or should I leave a small strip and adhere the velcro directly on the panels. I assume small gaps for the strips of velcro tape would not compromise the Dynamat too much ?.
Any thoughts.
Cheers
Tony

[Reads90]

You won't get it tight enough or secure enough with Velcro

What you need to do it what we call in the trade Dual Bonding. So stick the Dynamat to the car and then with some permeant carpet adhesive ( can be bought at Bunnings. ) stick the marine carpet to it. If you want to be able to remove the marine carpet and take it out then instead of permanent adhesive use what we call PS adhesive or Pressure sensitive adhesive. ( again sometimes called tackifier ) as it never really sets and you can take the carpet on and off the underlay when you want.




Ali

[tonyci]

Thanks for that. Do think either adhesive will take to the foil like surface of the Dynamat.

Tony

[Reads90]

Thanks for that. Do think either adhesive will take to the foil like surface of the Dynamat.

Tony

No it won't.

I am a carpet fitter by trade and now am the Dunlop Flooring Qld State manger and we are the leaders in carpet Underlay in Australia. We have products the same as Dynamat which are used in hotels exhibitions centres and Airsports all over the world using the same system.

[tonyci]

Thanks Again. I think I will try and track down some PS Adhesive.
Cheers
Tony

[Dougal]

Gluing carpet to the mat will transmit more noise. You need an insulation layer like closed cell foam in between and not bonded. Fix the carpet at the edges only.

[manic]

might be better off laying down a layer of closed cell foam on the dynamat and then some thick heavy rubber cut to size - the weight of the rubber will old it all down. Vertical sides you could bond or use a strip of aluminium extrusion and screw/rivet.

[jerryd]

No it won't.

I am a carpet fitter by trade and now am the Dunlop Flooring Qld State manger and we are the leaders in carpet Underlay in Australia. We have products the same as Dynamat which are used in hotels exhibitions centres and Airsports all over the world using the same system.

Have you got enough off cuts to do a lwb series 3 in the back of your van ? :wasntme:

[Reads90]

Gluing carpet to the mat will transmit more noise. You need an insulation layer like closed cell foam in between and not bonded. Fix the carpet at the edges only.

How do you come up with that. I can't see how it make a noticeable difference to noise if it is glued or lose lay the carpet

Also the carpet will ruck and stretch in the middle if you do that. The marine style carpet is a needle pinch and designed to be stuck all over and not stuck around the edges. It does not have the strength in the backing for that.

And if you want to use closed cell foam then why bother with the dynamat.

[manic]

And if you want to use closed cell foam then why bother with the dynamat.

Dynamat is quite heavy for its thickness and bonds to the panel reducing vibration more effectively than straight stuck down foam.

Use dynamat to dampen vibration, a layer of closed cell to absorb airborn, and then kill with a top layer of heavy rubber.

Why use carpet?

[Reads90]

Dynamat is quite heavy for its thickness and bonds to the panel reducing vibration more effectively than straight stuck down foam.

Use dynamat to dampen vibration, a layer of closed cell to absorb airborn, and then kill with a top layer of heavy rubber.

Why use carpet?

What I was meaning was why use Dynamat and then a closed cell foam and then a carpet. That is all over kill.
Either use Dynamat or closed cell foam.

As for carpet. That is just for look as it is smarter and looks better. It acoustic properties are marginal.

Here is the back if my 110.

https://www.aulro.com/afvb/images/imported/2013/03/834.jpg

[Dougal]

How do you come up with that. I can't see how it make a noticeable difference to noise if it is glued or lose lay the carpet

Noise is transmitted vibration. If you bond everything together, it transmits vibration (noise) quite well. Which defeats the purpose of the exercise.
If layed over and fastened at edges or at intervals it is far better at not transmitting noise.


And if you want to use closed cell foam then why bother with the dynamat.

Closed cell foam and dynamatt work in completely different ways. They are not interchangable for noise reduction.
Dynamat by itself is very poor at stopping noise. But combining a deadener (dynamat, roof-flashing tape etc) and an insulation layer (closed cell foam) with a top cover (carpet or rubber) you get a very good result.
The heavier the top cover, the better.
The layers also need to be able to move slightly to dampen vibration and the more layers the better. Two layers of 3mm foam are better than 1 layer of 6mm foam etc.

You are worried about overkill, but your original idea of gluing carpet to dynamatt is just wounding the noise and letting it die a miserable death somewhere inside.

For the next tip, deadeners (dynamat, roof-flashing tape etc) does not need to be full cover. You only attach enough to deaden the panel and stop it ringing.

If you are worried about the carpet bunching, I would glue it to something more solid (sheet of hard-board, HDPE plastic etc) that lays on top of the central floor. For the sides it'll support well being fastened at the edges.

I run similar marine carpet in the back of my work car. But it's not bonded to the floor.
The floor is steel deck, which has the factory tar deadener stuck on.
On top of that is 10mm closed cell foam.
On top of that is the factory vinyl flooring.
On top of that is the wooden organiser rack bolted down gently at the corners and covered in grey marine carpet.

This works very well, the factory deadener stops the floor ringing, the 10mm foam stops the higher frequencies and the rack on top stops the lot from drumming by providing more stiffness to the floor than dynamat/flashing tape can.

[tonyci]

Thank you to everybody who contributed to this thread.
Since asking the question and due to the discussion on this thread I have undertaken further research.
Dougal you are correct in what you say for optimum noise reduction and Reads90 you are correct as far as "look " is concerned.
AS always a bit of a trade off.
Cheers
Tony

[flagg]

I found dynomat to stop a lot of road noise on its own, and have had no problems glueing Velcro to it, and also to marine carpet. I'm going to add some closed cell foam too (also velco'd in).