# Ardex SD-F Feather Finish and SLC



## angus242 (May 1, 2008)

Mapei Ultraplan 1 Plus can be poured to 1 1/2" thick over approved surfaces.

However, your idea about feathering has 1 glitch. If you plan on using Ditra, the installation instructions state to use modified under Ditra when laid over plywood and unmodified when used over cement. So as to not void the Schluter warranty, you see the issue.
That said, using modified thinset over the entire area isn't hurting the installation. Modified thinset over cement works but the curing time is dramatically longer. I mean days longer. If you have the time, you could feather the SLC and then lay the Ditra. Wait a few day and then tile.
If time is a factor, float the entire area with SLC.
Whatever you do, make sure you read and follow the directions of the SLC. Some require the use of a primer before installing.


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