ᐅ The base plaster is peeling off in some areas after three years.

Good day,

I could use some information regarding a problem with the base plaster of my house. The house was newly built about 3 years ago. At my request, it was plastered with a mineral plaster, which was then painted with a silicate paint. The house has no basement and was built on a concrete slab, which is, of course, also insulated. After 3 years, the plaster at the base area is starting to peel. At first, lighter spots appeared before the plaster began to come off. I am not an expert in this field... Could it be that

a) the wrong type of plaster was used at the base area?
b) the wrong type of paint was used at the base area?

Perhaps the pictures can reveal more about the cause.

Regards, Andreas S.

p.s. I am currently unable to upload pictures. I will provide them later.

oman68623 schrieb:
Good day,

I could use some information regarding an issue with my base coat plaster. The house was newly built about 3 years ago. At my request, it was plastered with a mineral-based plaster, which was then painted with silicate paint. The house has no basement and was built on a concrete slab, which is, of course, insulated. After 3 years, the plaster at the base area is starting to flake off. Initially, lighter spots appeared before the plaster began to detach. I am not an expert in this... Could it be that

a) the wrong plaster was used in the base area?
b) the wrong paint was used in the base area?

Maybe the pictures can reveal more about the cause.

Regards, Andreas S.

P.S. I cannot upload pictures at the moment but will provide them later.

There are many types of mineral-based plasters. Try to find out the manufacturer and product type. What was the plaster applied to—directly onto the concrete base or is there perimeter insulation on top of it?

Thanks first of all for the reply. It is a plaster from Schwenk. Insulation is present. It appears as if the moisture is being drawn upwards from the bottom.

oman68623 schrieb:
Thanks first for the reply. It is a plaster by Schwenk. Insulation is present. It looks like the moisture is being drawn up from below.

First of all, I am not a professional, but I have had to acquire some knowledge out of necessity. Schwenk offers many plaster products. The manufacturer is secondary; the products used by a manufacturer are what really matter.

Without more detailed information, it is not possible to say anything from a distance. Take a look at the specification text to see how the assembly was supposed to be, and then compare it with the contractor’s invoice to see how it was actually done. To my knowledge, the assembly should be as follows:

Concrete base -> Perimeter insulation -> Mesh reinforcement with appropriate mortar -> Top coat plaster -> [...]

The part that is below ground level must also be sealed, meaning

[...] bitumen-based waterproofing membrane -> dimpled membrane (drainage membrane).

Then the base should be sufficiently protected against moisture, and therefore the plaster should not crumble.

Thank you. I will check on that. Although it will be difficult for me to determine whether it was carried out according to the contract.