Noise reduction techniques. Which is best?

[D in Davie]

I've seen a few methods people have tried to reduce the noise and heat coming into the MH from the dog house but I wonder which is the easiest to try and most effective. Speaking of easy, has anyone tried spray insulation on the underside of the dog house. The "Good Stuff" you can get at home depot looks deceptively easy. Just spray it on, let it cure for 24 hours then trim off excess. There has to be a catch.

[BFlinn181]

I'd think the catch is it's flammable. This from Great Stuff Insulating Foam Sealant: "Cured foam is combustible and will burn if exposed to temperatures above 240°F (116°C). Do not apply GREAT STUFF™ foam around heaters, heat lamps or recessed lighting fixtures, radiators, furnaces or fi replaces where it could contact heat conducting surfaces." Pretty much describes under an engine cover with hot manifolds and the like.

Dynamat has a number of sound deadening and insulating materials made for what you desire.

Dynamat.com | Dynamat Sound Damping | Thermal Solutions

[Glenn NK]

I agree with BFlinn. I had our carpets replaced last year, and I investigated the pros/cons of improving the sound insulation on the doghouse.

I talked to a shop at a marina and their product was used to insulate marine engines - but mostly the enclosures have flat surfaces.

The product is very good (can't recall the name) but what I learned from them:

1) it's really expensive,

2) requires expensive adhesive that won't melt/break down in the heat,

3) is very stiff so it can't be easily bent to fit the curves (mostly compound curves). This would require cutting the stuff into small strips and would take a fair bit of time and would result in some waste.

It might be easier (and probably just as effective) to remove the carpet, apply some insulation to the top surface (it's rough fibreglas and most adhesives will stick to it). Then re-carpet.

Glenn

[HappyGuy]

I used to install competition entertainment setups for cars. Among the sound deadening products I've used the dynamat products are hands down the easiest to install and the most durable. Liquid products are tough to get an even coverage. To do it right you need a spray gun, lots of masking material, and the patience to do three or more coats. Spray foam is extremely flammable and extremely toxic when on fire. Do not use it in an engine compartment!

Class A or C? If you're doing this for a C I used dynamat xtreme applied sporadically to the flat metal surfaces to cut down on vibration or ring transmissions. Then I used the thickest Dynapad under the vinyl. The pad cuts easily with kitchen shears or heavy scissors. It took me around 6 hours to completely remove my interior, add the mat and pad, tape the seams and reinstall the interior. Post install the engine is barely audible during normal driving but you can still hear a slight drone. Wind noise in the house section and an exhaust leak out back are much more pronounced now. The engine is still loud when it downshifts but it's not deafening anymore. The wife and I can carry on a conversation at normal volumes and the floor is no longer hot to the touch except right where the doghouse meets the floor. You can't insulate there due to clearance issues. Total cost was around 360.00.

If you're doing an A and you're concerned primarily with the engine cover then consider their hoodliner product.

[D in Davie]

Thanks for the answers. I guess there is no easy way to do this. The whole fire hazard thing would be a serious downside to using spray insulation. Thanks

[Fuzzybeard]

Just a FYI. Great stuff has a fire block insulation that has very high heat resistance. It is orange and was sold in the same area as the regular at my store. I did use this for a large gap I had in the doghouse due to bad installation.

[Johndale]

http://www.cascadeaudio.com/car_noise_control/I12.htm
This is what I used under the shell and used aluminum tape to seal edges. Used 3m spray glue to hold in place.


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