I have an old cast earth cellar where large parts of the walls have come loose and fallen off due to moisture, frost, etc., over the years. The earth cellar is now drained and sealed externally, so water no longer leaks in. However, I now need to fill in the large holes in the walls. The holes are estimated to be 3-6 cm deep, about 30-50 cm high, and cover roughly 15 m of the wall more or less. I don't have the energy to apply mortar in layers of 1 cm. Can I just skip that, apply it thickly in one go, and fill any cracks, or should I start with something like fine concrete first to build up the base and then finish with mortar?
Attaching some pictures. I have glued Styrofoam in the places where the holes are deepest. I have tried using c-bruk on some spots now which are 3-4cm thick. Two days later I don't notice any problems. No cracks or anything like that. Feels stable when tapping on it. It is cool and completely free from direct sunlight. Could it be that it's fine with thicker layers than 1cm in that case?
Building conservationist
· Malmö
· 254 posts
What material is underneath?
But regardless, you can plaster more than 1 cm at a time, 2-2.5 cm with regular plaster when filling in.
It doesn't matter much if it cracks when it dries if more layers are to be added. Just push the cracks the next day if you're going to apply more.
However, there should be a lot of movement in that wall, so I would even it out and use a mesh when there is about 2-1.5 cm left to the final surface and skip the styrofoam. If you want to fill out, it's better to use some bricks that you cut into suitable pieces.
But regardless, you can plaster more than 1 cm at a time, 2-2.5 cm with regular plaster when filling in.
It doesn't matter much if it cracks when it dries if more layers are to be added. Just push the cracks the next day if you're going to apply more.
However, there should be a lot of movement in that wall, so I would even it out and use a mesh when there is about 2-1.5 cm left to the final surface and skip the styrofoam. If you want to fill out, it's better to use some bricks that you cut into suitable pieces.