To Sound Deaden or Not to Sound Deaden?

[ladybird_bus]

For those of you who used sound deadening mats (like kilmat), where and how much did you use it? Do you feel it was worth it?

The total wall and floor square footage for our bus is around 550 sq feet, which would add up to quite a bit of $ if I cover every inch in the mats, plus insulation.
I want to do a good job but also don't want to waste money if, say, just doing the floor will suffice.

[peakbus]

Someone posted about using Lizard Skin spray throughout their bus. It is pricey. I found it didn't help much with my engine noise but I bet it would help on panel vibration noise. I wonder if you need it though if using spray foam insulation? I would think the spray foam coating the panels would minimize the rumble. I plan to have walls/ceiling sprayed and likely use rigid on floor and below the chair rail. I don't know if gluing rigid foam down will help as much on the floor? That's where I could see the Lizard skin or mat being helpful.

[ladybird_bus]

Originally Posted by peakbus

Someone posted about using Lizard Skin spray throughout their bus. It is pricey. I found it didn't help much with my engine noise but I bet it would help on panel vibration noise. I wonder if you need it though if using spray foam insulation? I would think the spray foam coating the panels would minimize the rumble. I plan to have walls/ceiling sprayed and likely use rigid on floor and below the chair rail. I don't know if gluing rigid foam down will help as much on the floor? That's where I could see the Lizard skin or mat being helpful.

Interesting. Thank you!
The fibreglass we've just revealed in the ceiling is in really great shape. I was hoping to leave it in, spray in the expanding stuff to fill some gaps, add a layer of reflective heavy-duty foil over the top and call it good. The BF is pushing for spray in foam instead and darn it, maybe that would be a better way to go.

[Tango]

Go with the foam if you can afford it. The fiberglass is pretty much worthless as insulation...(but is great at holding moisture). Also, the foam greatly reduces vibration and lowers road and engine noise. Just make sure to use closed cell foam.


Best of luck on the build.

[o1marc]

Originally Posted by ladybird_bus

Interesting. Thank you!
The fibreglass we've just revealed in the ceiling is in really great shape. I was hoping to leave it in, spray in the expanding stuff to fill some gaps, add a layer of reflective heavy-duty foil over the top and call it good. The BF is pushing for spray in foam instead and darn it, maybe that would be a better way to go.

The batt insulation there from the factory is not very effective and really doesn't insulate that much. You would be much better off removing it and replacing it with something more efficient. Rigid foam board is the easiest and cheaper than spray foam.

[crowcreekcabin]

I used self adhesive 80mil butyl on the firewall and floor board under the drivers feet and the tranny cover...

I also have carpet mat and carpet over the same area... so... not sure what helped more, but VERY happy with the resulting lack of engine noise. I have to use the tach at low speeds because I can't hear the engine like I used to..

Put some on the underside of some other strategic metal panels as well. (hood, and inside the space above the windshield).. Pleased with the change in acoustics.. quiet inside now instead of tinny. Sound just dies instead of bouncing around echoing like an empty gymnasium like it did when completely empty.

Drove empty all the way from California to Alaska... wow... that was noisy..
Sooooo much better now.

This also changed with insulated walls and wood paneling, so not entirely from the sound deadener, but I think it helped...

[Yukon Cornelius]

Tracking...

My theory is place where you may not have space for insulation it would be a good spot, drivers area (depending on config) firewall, hood, stairs, etc.

[EastCoastCB]

Originally Posted by ladybird_bus

Interesting. Thank you!
The fibreglass we've just revealed in the ceiling is in really great shape. I was hoping to leave it in, spray in the expanding stuff to fill some gaps, add a layer of reflective heavy-duty foil over the top and call it good. The BF is pushing for spray in foam instead and darn it, maybe that would be a better way to go.

If leaving the fiberglass don't even bother spraying foam in between. Go foam or just leave it be, IMO.

[Ninjakitty]

I put kilmat in the front area (need more for the firewall and driver's feet area) the stairwell, and on the doghouse cover. Carpeted the doghouse cover as well.there has been a reduction in engine noise.

[WoodenYouKnowIt]

I have an old Volvo Sedan that I put Dynamat in a few years ago. I put the stuff everywhere I could and that included the above the headliner. The Dynamat was really pricey and I ran out before I had everything covered. I couldn't afford any more Dynamat so I finished the job with this stuff from Home Depot. Here's a link:

https://www.homedepot.com/p/USEAL-US...2AF6/202086180

With the exception of the HD stuff coming in 6" wide rolls, it's the very same stuff as Dynamat.

When I got done the car was Cadillac/cathedral quiet on the inside. Also, the doors gave these beautiful solid thuddy sounds when slamming them. Of course, Volvo doors are very good anyway.

One thing that was dissappointing though was that when I was running about 70 to 80 down the interstate, all the noise was coming back. This was not the fault of the sound deadening. Rather, it was because all of the window seals, grommets and other things that are supposed to seal off the passenger compartment had all degraded over the life of this car. This is the reason that many people go to the trouble of applying the mat material and still don't get what they were hoping for. When I started tracking down all the places where wind was getting into the car and making noise in the process, I really started getting the results I wanted.

[GWRider]

Originally Posted by ladybird_bus

Interesting. Thank you!
The fibreglass we've just revealed in the ceiling is in really great shape. I was hoping to leave it in, spray in the expanding stuff to fill some gaps, add a layer of reflective heavy-duty foil over the top and call it good. The BF is pushing for spray in foam instead and darn it, maybe that would be a better way to go.

I agree with your BF to remove the fiberglass and use foam. Here are some other reasons why from one of my earlier posts:

Insulation in walls and ceiling - Page 2 - School Bus Conversion Resources

[Rovobay]

I would love to see some pics of folks deadening efforts in their buses....

[ladybird_bus]

Thanks for the replies, everyone!
Foam it is.
I think we're going to buy a DIY two-component kit to use on the ceilings and the walls below the windows, rigid foam boards for the floors and sound deadener plus carpet around the driver's seat.

[ladybird_bus]

Originally Posted by WoodenYouKnowIt

I have an old Volvo Sedan that I put Dynamat in a few years ago. I put the stuff everywhere I could and that included the above the headliner. The Dynamat was really pricey and I ran out before I had everything covered. I couldn't afford any more Dynamat so I finished the job with this stuff from Home Depot. Here's a link:

https://www.homedepot.com/p/USEAL-US...2AF6/202086180

With the exception of the HD stuff coming in 6" wide rolls, it's the very same stuff as Dynamat.

When I got done the car was Cadillac/cathedral quiet on the inside. Also, the doors gave these beautiful solid thuddy sounds when slamming them. Of course, Volvo doors are very good anyway.

One thing that was dissappointing though was that when I was running about 70 to 80 down the interstate, all the noise was coming back. This was not the fault of the sound deadening. Rather, it was because all of the window seals, grommets and other things that are supposed to seal off the passenger compartment had all degraded over the life of this car. This is the reason that many people go to the trouble of applying the mat material and still don't get what they were hoping for. When I started tracking down all the places where wind was getting into the car and making noise in the process, I really started getting the results I wanted.

Thank you! This was really helpful.
Did you find there was a strong smell from the asphalt in those products when it got hot? I've read that sometimes there is initially but it dissipates over time. But I'm not crazy about adding in carcinogens if it can be avoided..

[Tango]

Sound deadening sheet metal successfully requires mass. Check the weight per square foot of any product you are considering. You will note that the price is in direct proportion to its' weight.


So is its' effectiveness.


The best can run 1-2 pounds per sf.


Good news is...the "good stuff" (unlike thermal insulation) does not need to fully cover large areas. A single square foot or so is often enough to quieten something like a car door.


The absolute best product is one I used years ago on my first conversion (a 40' BBAA)...sheet lead. Not exactly something the EPA would very likely embrace these days but was commonly used in buses and trains up into the '70's.


I bought three, four foot wide rolls at a garage sale at the Houston Metro Authority.


Yes. They were VERY heavy.

[turf]

i used some sound deadening on panels and like the result.

you don't have to cover the whole panel, you just need pieces that weigh enough to change its resonating frequency of the metal.

get some dynamat and put it on any rattle you hear now. a little can fix a lot of rattle

[WoodenYouKnowIt]

Originally Posted by ladybird_bus

Did you find there was a strong smell from the asphalt in those products when it got hot?

There was no smell of asphalt at all.

[ladybird_bus]

Originally Posted by WoodenYouKnowIt

There was no smell of asphalt at all.

Thanks!
And I really love the signature line on your posts, by the way

[PNW_Steve]

Originally Posted by peakbus

Someone posted about using Lizard Skin spray throughout their bus. It is pricey. I found it didn't help much with my engine noise but I bet it would help on panel vibration noise. I wonder if you need it though if using spray foam insulation? I would think the spray foam coating the panels would minimize the rumble. I plan to have walls/ceiling sprayed and likely use rigid on floor and below the chair rail. I don't know if gluing rigid foam down will help as much on the floor? That's where I could see the Lizard skin or mat being helpful.

When I drove my first bus home from the spray foam installer it was like driving a different bus.

It was SOO much quieter.

[vintageracer]

You can buy a lot of ear plugs for the cost of Dynamat or Foam insulation!