I am going to plaster a "storage bunker" that is 17 square meters, where the surface is of a coarser concrete. I know there's a specific name for the concrete but I can't think of it right now. I'm considering plastering 10mm (since the surface is quite uneven) and have followed a calculation I'm not familiar with, and I'm thinking of using this bag from Byggmax. Alternatively, I might use Fasadbruk from Beijers or go with putsbruk, also from Beijers. I used a formula that a user suggested earlier in a similar thread and concluded the following:
I calculated that I need 13 bags for 17 square meters with a 10 mm layer of plaster, what do you think?
I calculated that I need 13 bags for 17 square meters with a 10 mm layer of plaster, what do you think?
It probably depends on how skilled you are (I'm an amateur, but I have polished up a few 100 square meters of various kinds in my career at least). I went to plaster a part of the plinth of a stable at my parents' place, and it wasn't particularly enjoyable. The concrete was very smooth after the formwork plywood, and the floor was cast with quite strong concrete, the guys who delivered it said something like "Oh well, it needs to be real bridge-concrete too," so that it would withstand the wear and tear in the stable properly.
The sum of it all was that it almost became like plastering on a glass surface; I tried priming a part of it, but it almost made it worse, it absorbed absolutely nothing, and the mortar had a hard time adhering to the smooth surface. Ever since then, I've taken it a bit easy with watering and priming when plastering on concrete, at least as long as the concrete is relatively new/of higher quality.
The sum of it all was that it almost became like plastering on a glass surface; I tried priming a part of it, but it almost made it worse, it absorbed absolutely nothing, and the mortar had a hard time adhering to the smooth surface. Ever since then, I've taken it a bit easy with watering and priming when plastering on concrete, at least as long as the concrete is relatively new/of higher quality.
this surface is roughly uneven, and definitely not any bridge concrete 
but the bunker was cast in 1997, and has been exposed to all forms of weather since then. Could this have affected the concrete in any way that I need to take into consideration?
but the bunker was cast in 1997, and has been exposed to all forms of weather since then. Could this have affected the concrete in any way that I need to take into consideration?