ᐅ Required installation height is 12 mm, but the chosen vinyl flooring is only 4.5 mm thick.

Hello everyone,

Here is the issue: Our kitchen is being completely renovated, including installing a new floor. The selected vinyl flooring has a thickness of 4.5mm (0.18 inches) – the floors in the adjacent rooms are about 12mm (0.47 inches) high.
We would like to get close to that height at least. The first thought was to simply use insulation underlayment of the appropriate thickness. However, no matter where we look, we can only find underlayments approved for vinyl with a thickness of up to 2mm (0.08 inches). In contrast, for laminate or engineered wood flooring, underlayments of 5mm (0.20 inches) thickness are readily available. The temptation is definitely there to just use those...
What are your opinions and tips on this matter?
Thanks in advance.
Best regards,
N

What is the floor construction like? I’m afraid you can only level out the missing millimeters with filler, since too thick insulation layers would cause joints to appear in the vinyl flooring. That’s why they are only approved up to 2mm (0.08 inches).

Hello questioner,
If the height difference to adjacent components (or neighboring rooms) is 12mm and the PVC covering has a thickness of 4.5mm (4.5mm (0.18 inches)), the calculated height difference would be approximately 7mm (7mm (0.28 inches)).
If the PVC covering is glued, an additional approximately 3.5mm (3.5mm (0.14 inches)) is added for the adhesive layer. This leaves a remaining height difference of 3.5mm (3.5mm (0.14 inches)). The entire surface must be skim-coated beforehand anyway, and this allows us to easily apply the 3.5mm to 4mm (3.5mm to 4mm (0.14 to 0.16 inches)) thickness at this location.
Now, the example if the floor should be installed floating:
The height difference is 12mm minus 4.5mm (4.5mm (0.18 inches)) = 7mm (7mm (0.28 inches)) (see above).
Since the bare surface needs to be skim-coated anyway (highly recommended!!) and the kitchen area will be of manageable size, the additional costs for the leveling (up to a total of 5mm (5mm (0.20 inches))) are negligible.
This leaves 2mm (2mm (0.08 inches)) to be compensated by the transition profile into the adjacent room.
The last option is the most practical, as it avoids “half measures” in the new floor build-up; for example, applying a ramp-like leveling over 0.6m (0.6m (2 feet)) at room transitions, etc.

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Underlays beneath elastic floor coverings do not serve to compensate height differences! “Tamstar” correctly pointed out that unsightly joints (to put it politely) are almost inevitable due to foot traffic and point loads from furniture.
Which option you choose is entirely up to you.
I just want to mention that internal ongoing opposition from household members (if the work fails) will be far worse and more nerve-wracking than the minor additional costs incurred to properly build up the existing floor...
Best regards and good luck, KlaRa

Hello and thanks for the replies!
But first, I need to ask why you think that "the empty surface still needs to be filled"?
I actually want to avoid that because the surface is perfectly level, and besides, doing so would raise the rough construction height compared to the neighboring rooms, which could lead to similar or different issues in the future.
OK, if you say there is no insulation underlay that can gain me 5mm (0.2 inches) and make me happy, then maybe another approach:
Even though I’m reluctant, it might be advisable to discard the chosen vinyl flooring and select one from another manufacturer that is already 9mm (0.35 inches) thick by itself (for example, seen with Parador, Wineo, and Gerflor).
Best regards
N

Nanopixel schrieb:

That’s actually what I want to avoid—the floor is perfectly level, and raising it would increase the shell structure height compared to the neighboring rooms, which could cause similar or different issues later on.

You have to choose your lesser evil. Either you deal with problems now (which is why you’re asking here) or later on.

Options:
1. Use leveling compound, so the vinyl fits now, but later no other flooring type will work without removing the leveling compound.
2. Live with the small step.
3. Choose a different flooring. At 12mm (0.47 inches) thickness, tiles, glued two-layer parquet, or “thicker” luxury vinyl flooring on HDF with cork underlay, or laminate are possible.

However, I find plastic flooring simply too expensive compared to, for example, parquet—ignoring look and feel for now.

Why should it be exactly this vinyl flooring?
List the reasons and find a suitable alternative.
You can adapt what doesn’t fit – finding something suitable seems to be the smarter option.