I have heavy tree cover and while there is barrier under my river rock, years worth of maple seeds, leaves etc. have broken down into a layer of soil on top of the weed cloth in the rocks. Is bad enough we actually pulled up a section and tried to wash out the soil from the stone and put the weed barrier back down.
Your results might be better if you jave less tree cover and certainly will be good for a few years. Just wanted to point out barrier and stone isn't as permanent a solution as most folks presume.

 

I have river rock around house perimeter. It sits on top of clay soil, no fabric. Looks good but does trap some leaves and debris so I blow them every few months using a leaf blower. Never seen a weed grow in the river rock around our house.

 

The big problem with landscape fabric is that if you have trees in the area, roots will eventually grow through it and it will be impossible to remove.

 

Judging by the comments here there is no real benefit to paying extra then to have mulch taken out before putting down river rock around my house….. ?

 

I'm interested in this one too. I was going to put weed fabric on top of my existing shredded mulch and then place pea gravel. If I don't need the fabric, that would be one less thing to worry about.

 

More than fabric or mulch underneath, you should think about how the water will shed away from the house. In our case we have wide roof overhangs, so little rain water falls down on the immediate perimeter of the house. If you don't have overhangs, I'd advise first removing mulch, then compacting earth with a slope away from the foundation, and only then putting down the river rock. Even better would be to concrete the 2-3ft strip around the house for water to flow away but that's too much work for most people. If you just put down river rock (or gravel) and rain hits it in sufficient volumes, water will eventually travel down to the foundation and may cause problems for house in the long term.

 

I'm not sure there is any reason to remove the mulch but I would recommend putting down landscape fabric on top of the soil/mulch before putting down the river rock. Depending on how much water flows through the area the rock will sink down into the soil over time and disappear. I've never done it at the scale you're talking so I don't know how long it would actually take but I've seen it happen around downspouts especially.