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Advice on XPS Subfloor Squeaking

830 Views 22 Replies 12 Participants Last post by  Smokymtgirl03
Hi everyone. I’m in the early stages of converting a 159”. Currently working on the subfloor. The floor squeak is driving me nuts. Almost every location on the floor has some amount of squeak when stepped on, even after a couple rounds of trimming & shaping. Video attached. Any ideas? I'm on the verge of abandoning the foam-only layer and laying wood framing. Thanks for your help.

Video: Promaster XPS Floor Squeaking Example

Based on various threads in the forum I went with the following:
  • 1/2” ACX Plywood over 1” XPS
  • Cut & painted both sides of plywood the same day to try and minimize warping (still seems to be a light bow)
  • Did not fill the 0.30” floor channels, or adhere the layers together.
-1/4”+ gap between floor and all vertical surfaces
  • Small wood supports at slider and rear door openings.
  • Used M8 bolts at flat washers at factory tie-down locations.
  • Taped all XPS butt joints using foil tape.

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Reactions: Bruce in NOLA
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Van #2 2021 EXT
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Glad that fixed your issue @Skevern 👍

I hate squeaks or other noises also ,,, I drive Mrs.RV8R nuts with my obsessing about them 😁.

Now you can continue with your build to completion @ which time you load your van with gear such as utensils that will provide you with road music during drives over less than perfect roads;

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91 Posts
The factory wood floor is glued on no squeaking might try and find what they use.I put two layers of closed cell interlocking foam (Gym mat type stuff) on top of that then thin plywood and vinyl flooring in traffic area

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52 Posts

Any ideas on what to use as a permanent 'fabric layer' that doesn't invite mold growth? Some ideas:
  • Thin Underlayment foam
  • Painter's plastic tarp
  • Landscaping fabric
  • Just glue the plywood down to the XPS sheets, hope it works?

I'd pretty much guarantee that gluing the plywood to the XPS would stop squeaking at that interface, but if its also squeaking where the XPS meets the metal floor, it won't stop that.

I would say that you could do what us hillbillies do here in Tennessee, just turn the radio up louder, but that could get me kicked off the forum. I have used an underlayment foam in a Casita rebuild to help the floor stop squeaking when it was walked on, and it really helped, but so did the vinyl free floating floor.
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