Butyl Fat Mat Soundproofing on Roof?

gordo019

Member
A friend recommends Butyl on the floors, wheel wells, door panels, and window bays. I am wondering also about the van roof as well. I am going to insulation the roof (Thinsulate) but should I also Fat Mat (.80ml) the entire roof? Also, any ideas on how many square feet should be ordered (Fat Mat) for a MB 144” Sprinter?
 

mikesprints

Active member
Rap on it with your knuckles. You'll find very little is left to do. Most of the roof is already damped. Now the corner's where the roof meets the sides just a 1 1/2" X 6" strip will damp each of those.

25% is all you need any where else. I did a few pieces additional above the headliner and side walls and slider. If you don't have rear windows those are the biggest area's that weren't done, factory. Tap on the front fenders as those are big "rattler's", for comparison.

My original order was 35 sq. ft. Ive done the whole back of my 144 low roof and have 12 sq. left. At most I'll use another 2-3 on the front doors at best.
I did do the roof panels on the outsides for "rain" drop damping on the roof, not so much for me as for Fido. Dunno if it will really matter as no discernible change there. Note: If you do some on ceiling and get condensation after they may come loose. I had a few come loose when I did last spring after a snow and melt. insulate ASAP. Cold to warm temp change with humidity. Had beads of water dripping inside.
 
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hein

Van Guru
A friend recommends Butyl on the floors, wheel wells, door panels, and window bays. I am wondering also about the van roof as well. I am going to insulation the roof (Thinsulate) but should I also Fat Mat (.80ml) the entire roof? Also, any ideas on how many square feet should be ordered (Fat Mat) for a MB 144” Sprinter?
Thinsulate(TM) will do a great job reducing resonance when in contact with the sheetmetal panels. It's like holding a big thick fluffy blanket against it. There will be no resonance.

There is no need to install any of the mass loading/damping products you list but you might have a hard time convincing your friend. You can apply a piece of Thinsulate(TM) to a large resonant panel and test the resonance reduction for yourself. Invite your friend to experience it first hand.

Just Thinsulate(TM) the whole van and you'll be happy.
 

gordo019

Member
>>>>> "Just Thinsulate(TM) the whole van and you'll be happy.” This statement includes the floor area too?
 

Midwestdrifter

Engineer In Residence
Constrained layer dampers like adhesive butyl sheets have little or no impact on ridgid surfaces such as floors or curved metal panels. Even on large unsupported metal panels no more than 25% coverage is necessary. Covering all the floor roof, or walls is simply overkill and a waste of time and weight.

For walls thinsulate bonded on will provide resonance damping as well as absorption. Floors need a firm or rigid closed cell foam.
 

hein

Van Guru
>>>>> "Just Thinsulate(TM) the whole van and you'll be happy.” This statement includes the floor area too?
Sorry for the confusing statement. We recommend minicell closed cell polyethylene foam for under a plywood floor. Thinsulate(TM) in walls and ceiling.
 

DieselFumes

2015 4x4 2500 170 Crew
A friend recommends Butyl on the floors, wheel wells, door panels, and window bays. I am wondering also about the van roof as well. I am going to insulation the roof (Thinsulate) but should I also Fat Mat (.80ml) the entire roof? Also, any ideas on how many square feet should be ordered (Fat Mat) for a MB 144” Sprinter?
Rather than relying on your friend's advice, I'd suggest reading sounddeadenershowdown.com

If you added 100% coverage anywhere in the van, you'd be adding a whole bunch of weight for very little gain. Doing it on the roof is especially pointless because very little exterior noise comes from above, and the panels don't resonate that much anyway (factory damping is ~25% coverage).

I'd agree with Hein and MidWestDrifter about Thinsulate being a good damper.
 

gordo019

Member
If I eliminate the Butyl Fat Mat from the roof should I also eliminate it from most of the floor layering plan as well? or just Butyl the rear wheel wells?

If I eliminate the Butyl layer, I am left with 3/8” close cell foam, the MB OEM wooden floor and maybe an area rug on the floor area. Enough?

I am getting mixed messages, and looking for some advice on the optimal Butyl application locations.

Floor layering Option A:
-Butyl Fat Mat full 100% coverage
-3/8” Closed cell form
-MB OEM wooden floor
-area rug

or

Flooring layering Option B:
-Butyl Fat Mat ~25% coverage
-3/8” Closed cell foam
-MB OEM wooden floor
-area rug

Please vote!
 
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DieselFumes

2015 4x4 2500 170 Crew
If I eliminate the Butyl Fat Mat from the roof should I also eliminate it from most of the floor layering plan as well? or just Butyl the rear wheel wells?
The butyl based products are designed to reduce resonance. That's an issue with the big, flat panels in the walls. The floor is corrugated. It's much less likely to be resonating sympathetically with any external noise source.

Only you can decide how much sound dampening of what types you want to install. It's a cost and weight trade-off. The butyl may give you some benefit, but is it enough for the extra weight penalty? IMO the foam will give you more benefit on the floor because it's acting as a vibration damper too. A heavy weight foam or a rubber layer will have some resonance damping properties too.

From practical experience, I can say that slapping a layer of the butyl stuff on the wheel wells helped. I used Reckhorn and then a layer of Thinsulate on top of that on the wheel wells.
 

Advonture

Member
Sorry for the confusing statement. We recommend minicell closed cell polyethylene foam for under a plywood floor. Thinsulate(TM) in walls and ceiling.
Hein - the foam you refer to for the flooring, is that also known as Polyiso? Thanks,
 

hein

Van Guru
Hein - the foam you refer to for the flooring, is that also known as Polyiso? Thanks,
No, the minicell is a softer compliant (somewhat memory foam like) closed cell cross-linked polyethylene foam. Polyiso is a rigid foam which does not dampen vibrations like minicell does. We just started carrying an innovative resonance control product from 3M. It is an Engineered Damping Material (EDM) that is about 1/2 the weight of competing products like Noico, Fatmat and Dynamat. It is not necessary to line the whole vehicle with it but can be beneficial on the wheel tubs, on the cab door skins and on the cab floor.

All the best,
Hein
DIYvan
 

Advonture

Member
No, the
the minicell is a softer compliant (somewhat memory foam like) closed cell cross-linked polyethylene foam.
can you provide a link as to where I would purchase this?


Polyiso is a rigid foam which does not dampen vibrations like minicell does. We just started carrying an innovative resonance control product from 3M. It is an Engineered Damping Material (EDM) that is about 1/2 the weight of competing products like Noico, Fatmat and Dynamat. It is not necessary to line the whole vehicle with it but can be beneficial on the wheel tubs, on the cab door skins and on the cab floor.

All the best,
Hein
DIYvan
 

hein

Van Guru
We offer minicell floor insulation kits with optional Thinsulate layer at DIYvan.com

All the best,
Hein
 

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