Hello!
A few questions regarding plastering exterior walls made of lightweight concrete in the basement, so on the inside.
We want to do this to avoid seeing drilled holes and other things.
Plaster so that it creates somewhat irregular patterns, almost like they have in Mediterranean countries.
Is it possible?
Is it appropriate since such an exterior wall should “breathe”?
What type of plaster should be used?
A few questions regarding plastering exterior walls made of lightweight concrete in the basement, so on the inside.
We want to do this to avoid seeing drilled holes and other things.
Plaster so that it creates somewhat irregular patterns, almost like they have in Mediterranean countries.
Is it possible?
Is it appropriate since such an exterior wall should “breathe”?
What type of plaster should be used?
Hello!
Since the walls are not insulated, it's important not to trap moisture, just as you mentioned.
Limestone plaster breathes and you get the result you desire. It looks really nice, like a real old cellar.
// Snäckan
Since the walls are not insulated, it's important not to trap moisture, just as you mentioned.
Limestone plaster breathes and you get the result you desire. It looks really nice, like a real old cellar.
// Snäckan
Kalkputs you mix yourself from släckt kalk that you buy by the sack (about 120kr/sack) and putssand (size max 1mm) that you buy at the nearest gravel pit or where you get sand, makadam :-/.gerge said:
1 part kalk + 3 parts sand + water until the mixture becomes like thick putty. Mix lightly and then it's ready to use. Can be saved for the next day if you cover it airtight with something like plastic wrap.
Walls should be pre-watered before putting.
That was the simplest description... a good description can be found on the dinbyggare website.
gaia
There are a number of different suppliers of ready-mixed dry mortar and also pre-mixed wet mortar. The price is consequently higher compared to Gaia's suggestion. Maxit's 142/144 are perhaps the easiest to find.
It can also be mentioned that Maxit's support claims that the adhesion of lime plaster to [light] concrete is mediocre... I don't have my own opinion on the matter but followed their recommendation, i.e., reinforcing mesh. There is a finer mesh variant, similar to chicken wire, available in rolls in suitable quantities.
It can also be mentioned that Maxit's support claims that the adhesion of lime plaster to [light] concrete is mediocre... I don't have my own opinion on the matter but followed their recommendation, i.e., reinforcing mesh. There is a finer mesh variant, similar to chicken wire, available in rolls in suitable quantities.
No, well, I only have experience plastering without mesh on old lime plaster and regular red brick (?).swehjo said:
As long as the substrate is somewhat absorbent (like, for example, brick) and form-stable (not wood), it usually sticks without mesh, I have found
. I only know that lime plaster (after it has dried) is much more flexible and not as rigid as cement-based plasters are. Netting and straw mats used to be used when lime plastering on wooden walls (revetment) which were unstable, but I can't think of an explanation why one should have netting on concrete/light concrete. Maybe it doesn't adhere hard enough to the substrate?
gaia
That was supposed to be the problem. I'm a bit skeptical about this issue with poorer adhesion since the walls were previously plastered with lime plaster, without mesh, and it worked (except where moisture had penetrated, and a mesh probably wouldn't have helped there either).gaia said:
Anyhow, I reinforced to be on the safe side. Partly because - if I understand it correctly - lime plaster isn't always just lime plaster anymore, so to speak. A lot of strange things are often mixed into ready-made dry mortar to "improve this" and "enhance that," and of course, that changes the properties. I suspect that for 100% pure lime plaster, you have to turn to companies like Målar- or Gotlandskalk to get it, or mix it yourself.
Nothing like that should, of course, remain when working with mineral-based products.
Member
· Västra Götaland
· 545 posts
Have you checked that it's not BLUE AERATED CONCRETE!
G66 is gyprocs plaster mortar and gypsum comes from maxit...
On an aerated concrete wall that "might" have been painted, there's only one answer - plaster
And gaia, the adhesion you got on your brick is something entirely different from getting adhesion with a lime mortar on aerated concrete - even though I don't think it's a problem - INDOORS - never lime plaster on aerated concrete outdoors.
The small gain you make by mixing yourself for outdoor plastering is not outweighed by the risk you take by not using a controlled mortar from the factory - indoors it's completely fine.
The only thing you can plaster outdoors with lime mortar is brick and renderings.
Lime plaster is always lime plaster - unless you buy it from sto!
The additives made in lime mortar were previously done by the masons on the site - a bit of dish soap - a bit of potash - a bit of clay or something that made the mortar workable - but it was only the workability that mattered - how durable it became was anyone's guess.
If you bought dirty lime for external work - the dirty part was actually impurities that made the mortar hydraulic - it reacted with water - not with air as pure lime mortar does.
And that gerge didn't find any "limestone plaster" is not so strange - I've never heard of it
//LyckeK
G66 is gyprocs plaster mortar and gypsum comes from maxit...
On an aerated concrete wall that "might" have been painted, there's only one answer - plaster
And gaia, the adhesion you got on your brick is something entirely different from getting adhesion with a lime mortar on aerated concrete - even though I don't think it's a problem - INDOORS - never lime plaster on aerated concrete outdoors.
The small gain you make by mixing yourself for outdoor plastering is not outweighed by the risk you take by not using a controlled mortar from the factory - indoors it's completely fine.
The only thing you can plaster outdoors with lime mortar is brick and renderings.
Lime plaster is always lime plaster - unless you buy it from sto!
The additives made in lime mortar were previously done by the masons on the site - a bit of dish soap - a bit of potash - a bit of clay or something that made the mortar workable - but it was only the workability that mattered - how durable it became was anyone's guess.
If you bought dirty lime for external work - the dirty part was actually impurities that made the mortar hydraulic - it reacted with water - not with air as pure lime mortar does.
And that gerge didn't find any "limestone plaster" is not so strange - I've never heard of it
//LyckeK
