Hi,
we have a garden shed (formerly a greenhouse) that was previously plastered and painted with silicate paint.
Now I want to apply a smooth plaster finish and repaint it. I plan to apply a bonding primer before the paint. The floor is not waterproofed; it consists of natural stone slabs with paving joint mortar. So, some moisture may rise into the plaster, but I want to leave a small gap between the floor and the plaster.
I am not sure which finishing plaster to use. It should be as easy to smooth as possible.
Looking at Rotband bonding plaster and Rotband surface filler, I can’t see much difference. The surface filler is just significantly more expensive. Or would the BAUMIT fiber-reinforced facade and repair filler be better?
Maybe someone can offer some advice.
we have a garden shed (formerly a greenhouse) that was previously plastered and painted with silicate paint.
Now I want to apply a smooth plaster finish and repaint it. I plan to apply a bonding primer before the paint. The floor is not waterproofed; it consists of natural stone slabs with paving joint mortar. So, some moisture may rise into the plaster, but I want to leave a small gap between the floor and the plaster.
I am not sure which finishing plaster to use. It should be as easy to smooth as possible.
Looking at Rotband bonding plaster and Rotband surface filler, I can’t see much difference. The surface filler is just significantly more expensive. Or would the BAUMIT fiber-reinforced facade and repair filler be better?
Maybe someone can offer some advice.
Baumit is also suitable for the base area but has a slightly smaller grain size. So, it probably doesn’t make much difference. Should you always apply two layers? I would first smooth the existing plaster a bit, for example with a concrete grinder or by hand with a plaster float, then apply the bonding plaster, smooth it out somewhat with a facade filler, and sand it the next day using a random orbital sander. Or does it need to be smoothed with a sponge on the same day?
Knauf’s material adheres very well and can be applied thinner. It is more expensive but simpler to work with. A bonding plaster may need to be pretreated, for example with a mortar like SM. However, depending on the roughness of the substrate, it might still work. It’s always difficult to judge from photos alone.
Applying two coats usually results in a more even texture because it allows for a consistent application and the mortar dries evenly.
Ultimately, it’s a matter of personal preference. I would opt for two coats.
Applying two coats usually results in a more even texture because it allows for a consistent application and the mortar dries evenly.
Ultimately, it’s a matter of personal preference. I would opt for two coats.
The base coat and the SM 700 should both be float finished, ideally using a sponge float. Using just a sponge is also possible, but it results in a less even surface. Both are mortars based on lime-cement, meaning they harden relatively quickly, and due to their grain structure, sanding won’t achieve the desired effect. The timing for float finishing depends on many factors and is difficult to explain precisely. It depends on the weather conditions, the substrate, and the thickness of the plaster. The mortar should no longer be soft, otherwise, you risk overworking it and damaging the surface.
However, this will not create a smooth finish like the one typically found indoors. Look for images of “float finish plaster.” The visible grain can be slightly reduced by float finishing later or by gently scraping the surface after it has hardened. You will need to experiment.
However, this will not create a smooth finish like the one typically found indoors. Look for images of “float finish plaster.” The visible grain can be slightly reduced by float finishing later or by gently scraping the surface after it has hardened. You will need to experiment.