I'm in the process of a bathroom remodel and have a section of the underlayment that has apparently been glued to the subfloor.

I am doing a floating laminate click lock floor

Im concerned the change in height may be visible on the planks.

What options do I have? I tried a large scraper bar with no luck. Im debating just cutting out this section and replacing the subfloor, which would also require a new toilet flange.

Belt Sander should do the job... just wear a dust mask and put a box fan in the window to suck it out.

Looks to be 1/4" luan/underlayment, can either sand it down or just lay down a new layer over it. As you mentioned, consider the flange.

They sell many transition pieces to go from laminate to tile.....the wide ones do a good job of transitioning a little height difference. Flooranddecor.com has 100's of them. Have you tried heating the stuff to release the glue now, and then trying the scraper bar?

Additional info I forgot to add. Im going to put down a thin 1/8 inch foam underlayment between the subfloor and the vinyl planks.

Im not sure if this would be enough to ease over the height difference

Read the specs for the flooring you plan to use. They will list a maximum allowed variation of the levelness of the subfloor. Just eyeballing it in the pictures, I'm going guess your floor will not meet that spec and will need to be fixed. I'd give a belt sander a try, but I sure some one with more experience will have the right solution. On concrete floors, I've used a self leveling concrete mix, but that's probably not the solution for a wood subfloor.

Plus one on the belt sander.

Add a 1/4” underlayment to match the low area. Lauan is cheap. Now is the opportunity to do it right. Sanding down would be extremely dirty/dusty. Been there.

If the added thickness causes a problem elsewhere, I would go with your first idea, cut the thicker stuff out and put in new subfloor.

Plunge cut with a circular saw and chip it out.

Just kidding, I’d probably sand it down.

quote:

Originally posted by gpbst3:
Additional info I forgot to add. Im going to put down a thin 1/8 inch foam underlayment between the subfloor and the vinyl planks.

Im not sure if this would be enough to ease over the height difference

If you are using modern vinyl planks (which I would never recommend using vinyl in a bathroom ever) use the BEST underlayment. I like the eco ultra quiet premium underlayment. The cheap underlayment will make the vinyl noisy when you step on it and can feel it move under your feet. Makes the whole install crappy, you can take $0.69 a foot vinyl flooring and use a premium underlayment and almost not tell the difference from hardwood flooring.

If it's a bathroom do yourself a favor and use the ceramic tile that looks like wood.