Under carpet soundproofing, felt or foam?

[chrisbladen]

What is peoples experience with floor soundproofing? I was about to buy a pre cut kingsman felt underlay but somebody told me to check out the foam alternative as it doesn't hold water if it was to get there.

I found these on ebay which seem faily resonable so i was just wandering what peoples experiences am with the felt and the foam?

https://www.ebay.co.uk/itm/162970103813

[ahebron]

I would follow the opinion of those wise people.
Our cars never left the factory waterproof and I am pretty sure not many are these days. 
I always remove felt from my old cars, if only to stop it smelling! 
Plenty of modern options about these days.

 

[Colin Lindsay]

1 hour ago, ahebron said:

Plenty of modern options about these days.

...and the best place to get it is a scrapyard. They usually throw it away so will sell it very cheaply. People Carriers are a good source, if you find one with a large flat rear area you can get quite a large sheet from it. It's both fire retardent and waterproof. Any yard with relatively new vehicles should have some that hasn't been sitting for years, so will still be quite fresh.

[chrisbladen]

14 minutes ago, Colin Lindsay said:

...and the best place to get it is a scrapyard. 

So are you saying it is best to use felt or foam? Sorry i might just be having a blond moment but im not quite sure what you am referring to!

[dougbgt6]

Colin means recycle something taken from a modern, which certainly won’t be felt.😊

Doug

[Clive]

But.... there are 2 types of sound deadening. The light foams, but you also need dense stuff.

The old fashioned bitumen sheets are very good. If you hear a car door "clank" when shut it is because there is no sound deadening pad fitted. Modern stuff from silentcoat etc. 

So I would use both types if you want a luxury feel/sound. The dense stuff on the flat panels (floor, bulkhead etc) and foam, felt if you must, absolutely everywhere..

[Adrian]

As Clive says. 2 principle sound types (sorry not an acoustics engineer so the descriptions are not necessarily accurate);

Resonance from pannel vibration - use of dense bitumen like silent coat deadens the panel.

Transmission - i.e. sound moving from a source via air vibration. So bulkhead, exhaust etc. Use a closed cell foam, eg dodo mat.

You dont need to fully coat the panel to achieve the silent coat deadening but advisable to fully cover with the foam where possible (didn't do the outriggers to make sure carpet fitted). I did and it is quieter, even if it is a pain.

[Colin Lindsay]

4 hours ago, chrisbladen said:

So are you saying it is best to use felt or foam? Sorry i might just be having a blond moment but im not quite sure what you am referring to!

Sorry for the confusion, Chris! I would call the old stuff - the wooly bitumen-backed stuff - felt; the modern alternative, that multi-coloured stuff you get under modern car carpets, is foam to me.

There's also sound deadening sheets, like the anti-drum panels, the self adhesive squares that are stuck on without cutting to shape, usually just in the centre of a flat panel to stop resonance and of course the heat-proof stuff. 

If you want a good, modern sound-proofing material that won't hold moisture, I recommended modern foam undercarpet sheets taken from a scrapped modern as a very cost-effective way of bulking out carpets and deadening road noise. And of course to further confuse things, I'm currently using rolls of the old bitumen-backed felt on my Heralds, as I bought it years ago at a show...

 

[chrisbladen]

7 hours ago, Adrian said:

 

You dont need to fully coat the panel to achieve the silent coat deadening but advisable to fully cover with the foam where possible (didn't do the outriggers to make sure carpet fitted). I did and it is quieter, even if it is a pain

Thanks adrian, and also great job on yours! Im either going to go down the scrapyard route or order myself some of this aluminum foil backed stuff. Looks great and the reviews seem good.

 

6 hours ago, Colin Lindsay said:

Sorry for the confusion, Chris! I would call the old stuff - the wooly bitumen-backed stuff - felt; the modern alternative, that multi-coloured stuff you get under modern car carpets, is foam to me.

There's also sound deadening sheets, like the anti-drum panels, the self adhesive squares that are stuck on without cutting to shape, usually just in the centre of a flat panel to stop resonance and of course the heat-proof stuff. 

If you want a good, modern sound-proofing material that won't hold moisture, I recommended modern foam undercarpet sheets taken from a scrapped modern as a very cost-effective way of bulking out carpets and deadening road noise. And of course to further confuse things, I'm currently using rolls of the old bitumen-backed felt on my Heralds, as I bought it years ago at a show...

 

Thank you colin. Il get on the blower to the scrappies 2mra, failing that, as i said im gonna go down the foam route! 👍