I sought some help for the lime plastering of my basement walls and ceiling. The people who were supposed to do the job wanted to perform the larger repairs with gypsum plaster, partly because it is more workable and partly because it can be applied in thicker layers at a time.
I checked with the manufacturer, whoever that was, and they strongly advised against using [that] gypsum plaster if there was a risk of penetrating moisture:
- partly because the gypsum is denser and does not let moisture through as well
- partly because it does not withstand it in the long run.
Then there may certainly be other, more suitable gypsum plasters. Personally, I think the surface becomes more vibrant with traditional plaster, but that is a matter of taste.
Additionally, using gypsum plaster as a base for lime plaster is not a successful combination in terms of adhesion.
I checked with the manufacturer, whoever that was, and they strongly advised against using [that] gypsum plaster if there was a risk of penetrating moisture:
- partly because the gypsum is denser and does not let moisture through as well
- partly because it does not withstand it in the long run.
Then there may certainly be other, more suitable gypsum plasters. Personally, I think the surface becomes more vibrant with traditional plaster, but that is a matter of taste.
Additionally, using gypsum plaster as a base for lime plaster is not a successful combination in terms of adhesion.
Member
· Västra Götaland
· 545 posts
Yes - the plaster becomes a bit softer when it gets moist but regains its strength when it dries...
And plaster has a poorer ability to allow moisture through than lime mortar - but you know how the lime mortar looks when it stands and is moist - it falls off the wall.
Plaster has the same ability to let moisture through as a KC-mortar...
And if there is pressing water in the wall, perhaps one should consider draining first
Rising moisture from the slab is not a problem for plaster to handle - it may need to be untreated or painted with KC-paint that you reinforce with a little adhesive...
And plaster has a poorer ability to allow moisture through than lime mortar - but you know how the lime mortar looks when it stands and is moist - it falls off the wall.
Plaster has the same ability to let moisture through as a KC-mortar...
And if there is pressing water in the wall, perhaps one should consider draining first
Rising moisture from the slab is not a problem for plaster to handle - it may need to be untreated or painted with KC-paint that you reinforce with a little adhesive...
The question of plaster on basement walls has been discussed a bit before here on the forum. LyckeK seems to be a guy you can't argue with when it comes to plaster and mortar matters, but Maxit's support has advised me twice against plastering basement walls below ground with gypsum plaster if there is a certain "moisture risk." For that reason, I will personally plaster all outer basement walls below ground with proper mortar and all other basement walls with gypsum plaster.