Sound Insulation for Stairwells Ideas?

[Tedd]

I own a GMC Savana based short bus and want to make it a bit quieter on the road.

I am building a cover to fit over the stairwell to block some of the engine and road noise when under way, but also to provide a couple more square feet of area in the bus. Obviously, this cover will have to be lifted and stored to use the stairs. I might even come up with a way to use this cover as a sort of table top when not needed to cover the stairs.

To help with the road noise, I am making this cover using 3/4 inch MDF with pine 2x2's glued and screwed to the bottom for strength. I will prime and paint the assembly to protect against moisture.

To further help with the noise I am thinking about gluing 1/2 inch thick pink stuff foam to the bottom of the MDF. I've selected these products simply because I don't know what else would work to absorb or deflect the sound ... any better ideas?

Also ... what else have folks done to insulate their stairwell against heat and noise? For starters, I removed the bottom two windows from the doors, covered the outside of the doors with sheet metal and filled the cavity with 1 inch white foam.

Thanks for the help.

[Drop out]

There are asphalt peel and stick roofing materials that are often used as a poor man's Dynamat. I hear they can off gas and smell for a while but they work to turn sound energy in to heat (tiny amounts) and damp resonance in panels. That type of insulation can get heavy.

I would try to fill the entire 2 by cavity on the bottom of your platform with foam and maybe skin the bottom with an acoustic ceiling tile. That won't add too much weight and you might be able to get a ceiling tile free if you can find an office building that is getting remodeled.

Other than that, spray foam and you could try to use a stethescope to find which interior panels are transmitting the sound in to the cabin.