Lime meets gypsum

[RosieB]

Hoping someone can offer some advice please. In the middle of a long renovation of our upstairs. Ended up back to brick. Have applied diathonite lime insulating plaster and wood fibre board to external facing walls. Internal walls and ceilings have been re-skimmed with gypsum. Our amazing plasterer is going to give baumit rk70 and then glatt a go over the woodfibre boards after the lime plasterer I found (with difficulty) had to cancel due to illness. The system seems fairly straight forward but he has very little lime experience so trying to help with research as much as I can! Our main issue is how to deal with the joins between the lime and gypsum. Our upstairs is in the eaves so we have corners, walls/cielings, and a could have verticals walls where the top half is gypsum (dormer cheek) and bottom is lime. We have discussed stop beads and mesh options but any thoughts appreciated!

 

[bobski]

Tricky one.

Even trickier without pics.

It's a shame you can't just lime the lot, all bases covered that way, where the pink meets white (as one will breathe and the other not), unless the juncture is well away from the cold wall - you WILL get mould!

May have to return a few inches off of each and start from there. Time consuming and a bit of agg.