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Maverick91119 Jan 2018 13:01Hello everyone,
I have the following problem. Ten years ago, I bought an old house and built an extension onto it. The extension was built using 36 Liapor blocks, covered with a cement-based render (mixed by myself), and then painted with a silicone resin paint from Maxit, after applying a Maxit primer.
On the old house, a remedial render from Maxit was applied, including reinforcement mesh, along with a corresponding primer mixed with quartz sand (the same was also used on the extension). Then, the wall was painted with Maxit silicone resin paint.
After just 2 to 3 years, on a wall surface of about 5 m² (54 ft²), the paint started flaking off, with the primer coming off completely as well. I then scraped off all the loose material and applied a normal primer without quartz sand. This lasted about 2 years; the newly painted areas remained intact, but where the old paint was still underneath, it began to detach again.
By the way, there are fine hairline cracks following the joints, and the wall is exposed to wind-driven rain.
Now, after 10 years, we wanted to repaint everything, so I consulted a painter about what I could do. He recommended filling larger irregularities caused by repeated painting with filler and then painting over it with a primer that is supposed to bridge small cracks. I also partially applied this primer to two other walls that had some flaking and hairline cracks.
I then primed the entire house and painted it with the paint he recommended and supplied. When I asked if it mattered which paint system was underneath, he said it didn’t, as long as priming was done.
Suddenly, the flaking got even worse. In the second winter after repainting, about 30% of the paint on the 5 m² (54 ft²) wall has already peeled off, and I would say another 50% is completely detached and still falling away. This is now starting on another wall as well.
On both walls, the hairline cracks following the joints are visible. Both walls were coated with the paint that is supposed to bridge these cracks.
What I also noticed is that where the paint has peeled off, ice forms behind it under certain weather conditions, and when it thaws, water droplets even come out of the now visible hairline cracks.
My suspicion is that moisture enters the render through the cracks, but due to the new paint system applied on top, it can no longer escape. As a result, condensation forms between the render and the paint, which then leads to flaking in freezing weather. The cracks might be caused by the render not being compatible with the masonry?
Remote diagnosis is difficult, but has anyone else seen something like this?
What possible solutions could there be?
Thanks!
Regards
Stephan
I have the following problem. Ten years ago, I bought an old house and built an extension onto it. The extension was built using 36 Liapor blocks, covered with a cement-based render (mixed by myself), and then painted with a silicone resin paint from Maxit, after applying a Maxit primer.
On the old house, a remedial render from Maxit was applied, including reinforcement mesh, along with a corresponding primer mixed with quartz sand (the same was also used on the extension). Then, the wall was painted with Maxit silicone resin paint.
After just 2 to 3 years, on a wall surface of about 5 m² (54 ft²), the paint started flaking off, with the primer coming off completely as well. I then scraped off all the loose material and applied a normal primer without quartz sand. This lasted about 2 years; the newly painted areas remained intact, but where the old paint was still underneath, it began to detach again.
By the way, there are fine hairline cracks following the joints, and the wall is exposed to wind-driven rain.
Now, after 10 years, we wanted to repaint everything, so I consulted a painter about what I could do. He recommended filling larger irregularities caused by repeated painting with filler and then painting over it with a primer that is supposed to bridge small cracks. I also partially applied this primer to two other walls that had some flaking and hairline cracks.
I then primed the entire house and painted it with the paint he recommended and supplied. When I asked if it mattered which paint system was underneath, he said it didn’t, as long as priming was done.
Suddenly, the flaking got even worse. In the second winter after repainting, about 30% of the paint on the 5 m² (54 ft²) wall has already peeled off, and I would say another 50% is completely detached and still falling away. This is now starting on another wall as well.
On both walls, the hairline cracks following the joints are visible. Both walls were coated with the paint that is supposed to bridge these cracks.
What I also noticed is that where the paint has peeled off, ice forms behind it under certain weather conditions, and when it thaws, water droplets even come out of the now visible hairline cracks.
My suspicion is that moisture enters the render through the cracks, but due to the new paint system applied on top, it can no longer escape. As a result, condensation forms between the render and the paint, which then leads to flaking in freezing weather. The cracks might be caused by the render not being compatible with the masonry?
Remote diagnosis is difficult, but has anyone else seen something like this?
What possible solutions could there be?
Thanks!
Regards
Stephan
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Maverick91123 Jan 2018 12:05I am just quite surprised at how severe it is. If only small flakes were coming off around the hairline cracks (joint cracks), that would be understandable, but the fact that patches about the size of a palm are coming loose, and not only right next to the hairline cracks, is puzzling. Is it really possible that moisture entering through the hairline cracks (joint cracks) travels between the paint and plaster in such a way that the entire wall is affected? I had also considered that the wall might be getting wet due to another reason, for example from the roof, but that seems unlikely since a second wall on the opposite side of the extension is also affected, showing hairline cracks and treated with a primer containing quartz sand. Maybe a solution would be to remove everything, stabilize the quite sandy cement plaster with a primer, and then apply a renovation plaster with a mesh reinforcement on top. The question is whether that would be enough to separate the cracking between the plaster and paint.
Regards, Stephan
Regards, Stephan
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