Wet plaster vs plaster boarding

[ruggers]

Two questions here.

 

I'm building a masonry build cavity wall, face brick exterior detached house, and I was going to be D&B boards to the external walls.

Because I'm looking for a good level of airtightness, I was going to parge coat the internal block work by means of a wet slurry mix or getting a plasterer in to parge it.

.

I'll be using masonry hangers so I'll want to cover the joist area myself before they're installed. Instead of dot and dab, I've been considering pricing it up for wet plaster to save the hassle of having to parge it, then hoping the installer does a good perimeter seal around each board.

 

1. If I wet plaster all of the external walls, how do we skim the internal reveals and catnic where I'd have cavity closers, or my own PIR insulation that plaster won' stick to. Do we have to board this area?
 

2.How are cables and 15mm pipes hidden in wet plaster. I'll need to drop some pipes down to the kitchen.