MarkJRust

I've recently been researching doing a bedliner'ed floor for my Cherokee, unlike others I will be reinstalling the carpets over the fresh bedlinered floor (DD here)...

I thought about using dynamat (let's not get into a dynamat vs xxxx please) on my floor but I really would like the protection from the bedliner too.

I've seen a few threads about people wanting/attempting to do bedliner OVER the Dynamat (this is done by scarring the top of the dynamat and this would get the best use out of the Dynamat's abilities) but I feel (and so did others) this would cause the bedliner to crack if/when the dynamat flexes.

Has anyone had good results with bedliner under the dynamat and if it will even stick well? Or does someone recommend it the reverse way (keeping in mind I prefer Floor Pan Protection > Sound Deadening)

EDIT: The orders would be Rustoleum -> Dynamat -> Bedliner -> Carpet OR Rustoleum -> Bedliner -> Dynamat -> Carpet
EDIT2: I'd be using roll on bed liner, spray for any tough to reach areas.

Let me know what you think, I'm hoping the best of both products --> Ultimate floor protection and a quiet ride.

Red82

I think I would do the rubber undercoating stuff over bedliner. But that's me personally. I just tgibj rubber over a hard material will insulate sound better. And I wouldn't go over carpet for the reasons you mentioned with the dynomat. Id primer, several good layers of undercoating, dynomat, and carpet.

kyledye25

I think bedliner over the dynomat may work. Yes it may crack....but how much? But also I feel dynomat in top on the bedliner would be ok to...in your case. Because the carpet it going on top. So if the dynomat don't stick who cares...the carpet is there to hold it down. I'm sure either way would work. I personally would do dynomat first....then bedline it. I think this way would work the best.

MarkJRust

Thanks for the reply, I'm slightly confused with your answer though. I wouldn't be using any rubber undercoating. Just bedliner and/or Dynamat.

This is the dynamat.

DirtyKK

i wouldnt waste the money on both if youre just putting the carpet back over it. i would just do the dynamat.

MarkJRust

I'm feeling this would work too.

FYI, Dynamat works best on direct contact with metal, with the least amount of air bubbles as possible. So, carpet just holding it down wouldn't really do much IMO.

MarkJRust

But, I prefer floor pan protection (bedliner) > sound deadening... :/

MarkJRust

http://www.jpmagazine.com/techarticl...its/index.html

I tracked down this article, they're putting herculiner over dynamat. I think this is the winner!

I'll have to do a thread for this while I do it.

MarkJRust

Something else important to note:

"Before applying the Dynamat, we strongly suggest putting down a layer of Herculiner, POR-15, or other rust-inhibiting protectant. After letting it dry, put the Dynamat down and then Herculiner - or something similar - on top of it."

Read more: http://www.jpmagazine.com/techarticl...#ixzz1oUbAvVOr

I'll be using Rustoleum. As it will leave the Dynamat the most metal-like surface to adhere to!

Red82

I guess I should have said id use undercoating instead of bedliner.

Think of it this way. If you go to a recording studio they don't use hard materials as sound proofing. Its softer material so it absorbs the vibrations. So you can had a softer material (undercoating) or a harder one (bedliner). The bedliner will work I just dont think it'll work as well as the undercoating. Plus there's a reason they use it at the factory. Plus I don't think it smells as bad as bedliner. Good luck either way and make sure and post a tutorial and let us know how it works for you!

andrewmp6

Have you looked at http://www.lizardskin.com/ its a spray on sound deadening.

DoWork25

My .02... dont waste the money on the dynomat stuff. A good rustolium primer and then a few heavy coats of the rubberized undercoating will protect much much better than just dynomat on the metal. And, use undercoating over the bedliner. I have used both methods and my favorite, spray, is the 3M rubberized stuff. The bedliner ended up cracking and flaking off even with good prep. I guess what I am saying is definitely use the undercoating UNDER your dynomat. that way if any water does start to eventually seem under the dynomat, its on the rubber undercoating instead of the metal.

salad

I was actually thinking the same thing. Strong bedliners advantages are being highly durable, resisting chipping and scratches. A DD with carpet all over the floor won't really have this requirement. As for Dynomat, most stick-on sound-deadening materials are heavy and soft.

Makes more sense to me to apply the rust-inhibiting primer, then instead of spending money on all that stuff with seems a little redundant, buy rubberized undercoating. I'm not sure how much Dynomat is, but I'm fairly certain the undercoating can be had for significantly less than a strong bedliner. So get that, get like 5x the amount you would have normally, and PILE it on. As many coats as you can. Presto!

I think it would be more effective than dynomat/bedliner combo. It would be more like a gigantic piece of Dynomat that just so happens to seal the floor. Bedliner over a soft material sounds like a great way to develop cracks and render the whole thing useless. But, as you noticed, for best effect it should have direct contact to metal. In other words, the greater the surface area, the more vibrations absorbed. Since most (all?) bedliner products leave a bumpy finish there wouldn't really be much for it to adhere to.

DoWork25

exactly. when i redo my floors that are a little rusty not too bad though, after all the metal work is done i plan on going over everythhing with a few good coats of the rubberized undercoating for the double use of sound deadener and protection. I may be doing the underside with a bedliner but will most likely opt for the rubberized undercoating here as well.

smoothlandin

I painted my new floors, let them dry, then laid a dynomat like product down, making sure that I covered any seams real good. It extends up to the door sills, and up on the trans tunnel and high on the firewall. It cost like 80 bucks, and works well, the sound inside was reduced dramatically, and no leaks either. Sounds like there's a number of ways to do it, good luck