ᐅ Combination of Tiles and Hardwood Flooring

@pst90:
I came across your thread via "Neige" and can respond as follows:

• Can there be issues with the heating system if different floor coverings are used on one heating loop, in our case tiles and the new parquet?

The answer is NO (there won’t be any problems).

• When “repairing” the screed, is there anything specific that needs to be observed or taken into account?

For example, when ceramic tiles are removed from a heated screed surface, the method matters. Using an inappropriate removal technique can damage the screed surface (which does not affect the heating loops since they lie at least 40mm (1.6 inches) deep), but this is not a problem; it may just require additional leveling or reprofiling work.

• Should the oak parquet boards be laid lengthwise (along the room) or parallel to the width? The dining-living area where the parquet will be installed is about 5 x 10 m (16 x 33 feet) in size.

This can’t really be said from a distance. Even with oak, there is a so-called spatial effect depending on the intensity of the wood’s texture. Ideally, the laying direction should be determined by how the light falls in the room (i.e., the position of the windows).

• Should the option of floating parquet installation also be considered?

In principle, this installation method can be considered. However, if the tiles remain underneath, problems can arise due to the increased thermal resistance. With floating installation, the unavoidable air gap results in a relatively high thermal resistance, which can cause heating issues during winter. The ideal method for underfloor heating is always a fixed installation (i.e., glued down).

• Is there any objection to using aluminum profiles at the edge where tiles meet parquet, with the profile having a 90-degree angle—one side toward the tiles, the other toward the parquet—and a silicone joint between the profile and parquet?

Basically, it should be noted that the tiles in the room where the parquet will later be installed are more than just bothersome. For the reasons already mentioned (also if the parquet boards or strips are glued down!).
If the tiles in a room have been removed, a step height of about 13mm (0.5 inches) remains (tile plus adhesive). Depending on the parquet construction you choose later, the thickness to be planned (parquet plus adhesive) will be around 18mm to 25mm (0.7 to 1 inch).
This means that toward the kitchen, there would be a step difference between 5mm and 12mm (0.2 to 0.5 inches).
A 5mm step is usually manageable, but 12mm or higher will cause a tripping hazard.
Solution in the latter case:
The cement screed is ground down in a ramped fashion by about 7mm (0.3 inches) from the living area to the kitchen over a length of approximately 0.6 m (2 feet) and the width of the doorway plus 20cm (8 inches).
At first glance, this might raise concerns about the screed’s structural integrity, but it does not. There are reasons for this which I won’t explain here. The screed’s load-bearing capacity remains ensured despite the thickness reduction!
By creating this ramp, we achieve an acceptable height transition to the kitchen, which can be covered by any suitable transition strip and only amounts to a few millimeters difference.
The approach with the aluminum profile is more for DIY enthusiasts without background knowledge — this path should be left to others :-)
---------------------------------------------
Best of luck: KlaRa

Thank you for your prompt response @KlaRa, I was a bit unsure about the underfloor heating. This will help the OP, and I am now well informed again.

@KlaRa Thank you very much for your detailed answers :-)

Regarding the affected "L"-shaped room: There is NO wall between the two sections (kitchen and dining-living area) because you mentioned a door, so everything is open! That means the ramp could be sanded down along the entire edge of both sections!?

It is out of the question to glue the hardwood flooring OVER the tiles; the tiles will be removed. Regarding tile removal: What is the best way to do this? Is it really possible to remove the tiles in a way that the screed does not need repairs?

I don’t know the current height of the tiles plus adhesive, so how do you conclude that there will definitely be a large step if the hardwood flooring plus adhesive is 18–25mm (0.7–1 inch)?

Regarding light exposure, there are windows and terrace doors on all sides of the room with (future) hardwood flooring. The long side faces the sun.

Regarding the aluminum strip: I probably didn’t express myself clearly. I don’t mean a small aluminum strip resting ON both floor coverings, but rather a stainless steel (Nirosta) strip with a 90-degree angle, where one side rests against the tile edge and the other side lies on the screed, with the hardwood floor glued "on top" of it.

Thanks for your constructive and quick answers! :-)

Best regards, Patrick

"Standard" porcelain floor tiles are usually 10 - 11mm thick, plus about 3mm of adhesive, which totals approximately 13-14mm (around 0.5 inches) thickness of the tiled surface.
Parquet flooring is naturally thicker, so you end up with a step of about 1cm (0.4 inches).
However, as someone already mentioned, a professional should be able to level this out.

If properly planned, including the thickness of tiles, parquet flooring, and adhesive, this can also be done without a transition strip.

And the tiles come off carefully. I removed them partly using a rotary hammer and partly by hand. The tile adhesive was then ground off with a diamond grinding disc.