I think I found a source for road noise.

[Pfflyer]

In my quest to reduce the road noise in my 2016 Melbourne I thought I would hit behind the seats in the chassis after doing the doors. Behind the seats is just carpet and it doesn't even go all the way to the B pillars. Anyway while I was back there I pulled off the transition piece from the cab to the coach just to see what was underneath. Not sure what other Jayco Class C's use but it is a piece of bent metal with an abrasive tread grip attached to the top like in this picture.


After I pulled it I found all that was underneath was vinyl flooring (no backing), a little bit of foam sealant to fill the gap between the vinyl flooring and the vertical piece of wood, and then there is the chassis frame, driveshaft and the ground. That is about a 4" x 60" gap for noise, heat and cold to come through.


After getting some advise I decided to screw vinyl flooring planks to the bottom of the coach floor (underneath the coach) reinforced with alum strips and have it rest on top of the vertical piece of plywood shown in the picture. This would leave a void about 1-1/2 -2" thick (thickness of the floor) on the coach side and taper down to 0 on the chassis side and be about 4" wide. My plans are to fill that void with MLV sound deadening mat and stick butyl automotive deadener to the bottom of the steel transition. Road noise levels are not bad as is but could be better. Most of the materials I am using are left over from my van conversion or other projects so out of pocket is close to $0. After this is done I will report back my findings which will probably be all the creaks and rattles from the cabinets, microwave and woodwork are louder now.

[campaholix]

Originally Posted by Pfflyer

In my quest to reduce the road noise in my 2016 Melbourne I thought I would hit behind the seats in the chassis after doing the doors. Behind the seats is just carpet and it doesn't even go all the way to the B pillars. Anyway while I was back there I pulled off the transition piece from the cab to the coach just to see what was underneath. Not sure what other Jayco Class C's use but it is a piece of bent metal with an abrasive tread grip attached to the top like in this picture.
Attachment 30853

After I pulled it I found all that was underneath was vinyl flooring (no backing), a little bit of foam sealant to fill the gap between the vinyl flooring and the vertical piece of wood, and then there is the chassis frame, driveshaft and the ground. That is about a 4" x 60" gap for noise, heat and cold to come through.
Attachment 30854

After getting some advise I decided to screw vinyl flooring planks to the bottom of the coach floor (underneath the coach) reinforced with alum strips and have it rest on top of the vertical piece of plywood shown in the picture. This would leave a void about 1-1/2 -2" thick (thickness of the floor) on the coach side and taper down to 0 on the chassis side and be about 4" wide. My plans are to fill that void with MLV sound deadening mat and stick butyl automotive deadener to the bottom of the steel transition. Road noise levels are not bad as is but could be better. Most of the materials I am using are left over from my van conversion or other projects so out of pocket is close to $0. After this is done I will report back my findings which will probably be all the creaks and rattles from the cabinets, microwave and woodwork are louder now.

Holy crap! That explains why it sounds so loud behind me while I'm driving!! I thought it was road noise coming thru the side door. I'm guessing I need to do the same thing to my 2016 Melbourne...can't imagine it would be any different than yours.
Thanks for sharing this...please post how it turns out.


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[Pfflyer]

I was thinking it was all the bare metal behind the seats barely covered with carpet in the chassis was the source. I don't think I will do the whole floor for now just behind the seats, under the seats bases and the tool and jack bin on the passenger firewall foot area. The MB flooring is pretty hefty to absorb the noise and the carpeting should help as well. There are MB flooring inserts that cover behind the seat bases in my crew van. I am not sure if they are not included in the chassis configuration or they got lost somewhere in the Jayco factory.

[Pfflyer]

Transition soundproof almost done. I did not have any MLV matting left or I could not find it. Anyway I put the vinyl floor planks in with the aluminum strips to hold it to the bottom of the floor. I had plenty of the butyl self sticking matting so I covered all the seams with it and I coated the vertical wood piece as well. I put the metal transition piece in and took a test drive. I still have under the seats and behind the seat bases left to do but it did make a difference with the road noise. Even the wife noticed so it might be a bigger difference than I initially thought. It is a two person job unless you are blessed with more than 2 arms and they are double jointed. I used a cordless impact with 1" self drilling screws because it looks like there is metal sandwiched between thin plywood at the edge of the floor where I was going to screw into. I pre drilled the alum strips. I ended up going with 1-1/2 wood screws because in the center of the RV I was having issues getting the 1" to hold. I might replace a couple of those with 2" long screws as long as they wont come up on the inside. Also in the center of the RV you will need about a 12" bit extension to get around the frame, drive shaft and exhaust. I went with vinyl flooring planks (12" x 24") because I had them already, they wont rot or rust, and they wont transfer noise as much as metal will. Sorry I don't have more pictures but this from underneath. The tan is the vinyl floor and the black stuff around it is the butyl mat cut up. You can see a little bit of the alum strip as well.