Self-leveling underlayment over existing floor

I have a newer addition with two rooms that has a cement slab and one room has ceramic tile laid. The addition is about 1 inch lower than the main house. I recently floated engineered hardwood throughout the remaining house and would like to continue the flooring to these rooms. What is your suggestion? Can I pour self-leveling cement over the existing floor to raise the floor the remaining height? Should I use a primer over the old slab? And can I pour over the ceramic tile without needing to rip it up? Since one room does not have tile, it is 1/4 inch lower than the one with tile, so the height is anywhere between 1/4" to 1" to raise.

[cproader]

Yes, you should use primer, and I would probably not recommend you level over the tile. It could cause the tiles to pop loose.......

[Kman]

I'm not familiar with any SLC's that can be poured an inch thick. That would be a lot of SLC, and very expensive.

What would be a good alternative?

[Floorguy]

micspoon said What would be a good alternative?

I would float two layers of ½" plywood, over a moisture barrier

[BrianM]

micspoon said I have a newer addition with two rooms that has a cement slab and one room has ceramic tile laid. The addition is about 1 inch lower than the main house. I recently floated engineered hardwood throughout the remaining house and would like to continue the flooring to these rooms. What is your suggestion? Can I pour self-leveling cement over the existing floor to raise the floor the remaining height? Should I use a primer over the old slab? And can I pour over the ceramic tile without needing to rip it up? Since one room does not have tile, it is 1/4 inch lower than the one with tile, so the height is anywhere between 1/4" to 1" to raise.

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Hi micspoon. Hire a local pro who has experience with this product. This job sounds way to big for a do-it-yourself project. If you are very experienced with either flooring or concrete work and have the right tools you might want to give it a shot. I recommend you don't.

ARDEX K 15 Self-Leveling Underlayment Concrete
ARDEX Engineered Cements

Portland cement-based, high-strength, fast-setting, non-shrinking underlayment. Mix with water, pour or pump, spread, ready!
Product Capabilities:
For use over concrete, metal, terrazzo, ceramic tile, wood and non-water-soluble old flooring adhesive residue (including cutback), on, above or below grade.
Pourable or pumpable. Installs from featheredge to 1-1/2" in one operation; up to 5" with the addition of proper aggregate. Designed specifically for fast leveling of floors, ARDEX K 15 provides a durable, flat and smooth floor surface with minimum labor and installation time.
ARDEX K 15 hardens quickly by hydration and drying. It will not shrink, crack or spall, even when applied in thick layers. Floor coverings can be installed just 16 hours later.
ARDEX K 15 is recommended and specified by most flooring manufacturers, architects, and contractors.

[Peter Kodner]

At one inch, you definitely will want to use aggregate. I would not advise a DIYer to do this themselves...

[the english guy]

My advice (well what we would do in the u.k) is use a ardex k15 with aggerate chippings for extra sturdyness up to the tile lever let dry, prime the whole lot including your tiles and then k15 over everything to give you a perfectly flat floor all one level

Probly wouldn't reccomend this if your a diyer