So my question is less about how to use the Self Levelling Compound but more the complications of using it.

For instance in my master bedroom we are looking to install LVP. I have laid down thick 25mm plywood and filled any gaps. This has done a wonderful job of flattening out the surface of the old wood floor underneath. However I am still aware of some larger variations in the height of the floor in some spots (possibly 5mm difference over a 20cm distance in places).

I figure one option is to use SLC.

My question is this: if I do use SLC in my upstairs bedroom am I going to cause problems for myself in the future if I have to get to something like a leaky pipe under the floor? If the floor had no SLC and only plywood then I'd be able to cut and lift out any sections where I need access to the pipes. But with SLC am I not sacrificing my ability to do that?

Furthermore, if I do have to take up the floor for an emergency and I chip away the SLC, is it easy enough to replace it again?

As I see it the only other alternative I have is to sand/plane the plywood down to level it but I have heard that it may cause a headache and be slightly less accurate.

Many thanks for your insight in advance.

  • Read the instructions for the LVP. 5mm will probably be within the difference allowed or very close to it. If it was more then you might need to level/flatten more.
    – crip659
    Commented Feb 6 at 14:18
  • You used 25mm plywood? If this is over existing boards and reasonably spaced framing, I'd rent a drum sander. If you actually have low spots, but you've fixated on the highs, there are products like Henry 549 (that particular one is expensive for large quantities, but requires zero prep work and is ready to bury in 30 minutes).
    – popham
    Commented Feb 6 at 18:47

1 Answer 1


5mm is very slight in the scheme of things.

The LVP will go over the floor with little problem just as you have it. It likes the floor to be flat rather than level. Give the LVP floor a little time after installation and it will gradually conform to minor fluctuations in the subfloor, such as a minor dip in a corner or such. If the dip is near the center of the room use some level patch compound.

Your reservations about what leveling compound will do if future repairs require removing the floor are understandable. The compound can be cut. It will probably crack from the floor moving. When repairs are complete it can be replaced. Smaller repairs can be done with level patch compound. However in your situation,it may not be needed.

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