Usage:

Before you start adding roughness layers you have to set up the Roughness Maps directory (where you have all your roughness maps) in the Addon Preferences. Once you do that you are ready to add Roughness Layers to your objects.

QRL Panel is available under the Item section of the N-Panel.

Hit Refresh to load all the roughness maps (loading previews might take a few seconds depending on the size of your textures)

UnTile Settings:

The addon also comes with its own basic UnTile node to randomize the textures a little bit so they don't look repeated.

It's not that great but gets the job done most of the time. The next version will include an option to add your own UnTile node.

Adding a Roughness Map:

With any object selected(object should have some material and roughness layers will be added to the active material of the object) open the QRL Panel and select any of your roughness maps and click "Add Roughness" to add that texture map.

A new roughness layer will be created with and you can control its  Brightness(Roughness Amount) and Contrast.

Using Z-Mask:

You can limit the effect of any layer to the bottom or top of the surface by using Z-Mask.

Toggle Z-Mask by clicking on the "Z-Mask" button.

By default, Z-Mask will limit the effect to the top of the surface but you can change it to affect only the bottom by setting the invert value to 1.

Reach defines how far it reaches to the opposite side.

Removing a Layer:

Simple click the Cross button to remove any Layer.