hausbaudre
2025-05-15 22:05:26
- #1
Hello home builder,
I am renovating the attic (= 3rd floor) of our end-terrace house from 1956. It has continuous ceiling slabs (concrete beams with a height of 14 cm spaced at 62.5 cm, with a 5 cm concrete slab on top). I have noticed severe cracks. I removed the white "filling" because it was already cracked at the original cracks and feels quite loose, thus providing no added value. It doesn’t seem to be gypsum; I suspect lime with a pinch of cement. This was applied either during the first renovation in the 90s or even earlier. So, they are not new.
While chiseling out, I only became aware of how extensive the cracks and holes really are. Although we also had cracks on the 1st floor (renovated last year), they were neither as numerous nor as pronounced. Back then, I also wouldn’t have noticed that cracks are visible on the ceiling to the upper floor. The largest crack is also exactly over or at a wall underneath.
From what I have read so far in the forum, I am uncertain ("cracks in concrete are normal" versus "a professional should look at it"), so I am attaching a few pictures that indicate the extent.
Thank you for your help, here are my questions
1. How critical should such cracks be assessed, or what danger do they pose.
2. Based on that: Is the insertion of concrete staples + resin sufficient, or should a specialized professional company handle it.
3. A black substance can be seen in the pictures. I cannot identify it. Most likely tar? Was it a common practice to tar and coat cracks with lime?
I am renovating the attic (= 3rd floor) of our end-terrace house from 1956. It has continuous ceiling slabs (concrete beams with a height of 14 cm spaced at 62.5 cm, with a 5 cm concrete slab on top). I have noticed severe cracks. I removed the white "filling" because it was already cracked at the original cracks and feels quite loose, thus providing no added value. It doesn’t seem to be gypsum; I suspect lime with a pinch of cement. This was applied either during the first renovation in the 90s or even earlier. So, they are not new.
While chiseling out, I only became aware of how extensive the cracks and holes really are. Although we also had cracks on the 1st floor (renovated last year), they were neither as numerous nor as pronounced. Back then, I also wouldn’t have noticed that cracks are visible on the ceiling to the upper floor. The largest crack is also exactly over or at a wall underneath.
From what I have read so far in the forum, I am uncertain ("cracks in concrete are normal" versus "a professional should look at it"), so I am attaching a few pictures that indicate the extent.
Thank you for your help, here are my questions
1. How critical should such cracks be assessed, or what danger do they pose.
2. Based on that: Is the insertion of concrete staples + resin sufficient, or should a specialized professional company handle it.
3. A black substance can be seen in the pictures. I cannot identify it. Most likely tar? Was it a common practice to tar and coat cracks with lime?