Personally id go neat its not the thickest of material anyways lash 2 coats on crack on it will be all good but consider the dry wall mushrooms mate if there is movement SBR wont fix this .. your aim is to pull the slabs back and sit on the dots you placed there originally ,
Regarding expanding...
Sounds like old plaster boards to me even with PVA if the moisture is gone from the boards , as in they have been slabbed for a while and heating has been on etc etc .
If they sucked in when you were coating they will have sucked in the wall adhesive too so maybe that didn't get a 100% hold so...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.