We have an old concrete stair that was probably cast in place when the house was built. In the last five years, it has started to crumble (probably due to salt used previously) and I've tried to repair it several times, but the repairs have crumbled away by the next year, and the staircase itself has deteriorated a bit more. I'm starting to get desperate. I would have preferred to keep it if it could be fixed.
How do you make a concrete repair last?
How do you make a concrete repair last?
Since it's impossible to know how the concrete in the staircase is composed, I suggest that you either completely remove the staircase, mold and cast a completely new staircase, or alternatively chip everything down to the reinforcement (which lies flat with the underside of the staircase about 3-5 cm above the 'bottom') and use the 'shell' that remains as a mold for a new staircase. Then you need to reinforce the cup again and place it with a 3-4 cm distance to the old one. Then set the form for the risers and cast a new staircase with the correct concrete composition. In this, you can add frost-proofing agents so that the concrete doesn't freeze/erode in the future.
Simply scraping off the eroded parts is not enough. The problem lies in the fact that the concrete is not correctly composed. Often, there has been skimping on the cement. And there's nothing that can be done about it now.
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Byggaren
Simply scraping off the eroded parts is not enough. The problem lies in the fact that the concrete is not correctly composed. Often, there has been skimping on the cement. And there's nothing that can be done about it now.
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Byggaren
What happens in all masonry, plaster, and concrete is that salts are precipitated through thermal moisture migration. (Seen as white 'curtains' on a basement interior wall, for example.) This is the first stage of leaching, which causes the lime and cement in the mortar to lose their binding effect. Then the finer gradation of the aggregate (gravel and stone) weathers (or more accurately: disintegrates) internally and damage occurs. It's a long-term process that takes several years to develop. In some cases, it can appear after just a few years. Usually, in a masoned/plastered exterior basement wall.akhe said:
In your case, the stairs are heated from the top by the sun, and the moisture moves to the underside, where it probably hasn't been visible or has been taken for granted since the moisture from the ground condenses and rises through the solar heating and adheres to the concrete underside. It's natural for the stairs to weather/disintegrate first from the front side.
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Byggaren
Maxit has a primer called bethoheft and a special repair concrete, the problem is that you need to have a layer of at least 10mm! so you need to chisel away at least 10mm as mentioned.akhe said:
I repaired mine with good results by first chipping away 3-5 cm from all exterior surfaces. Then I built a mold and cast a new surface layer using bagged fine concrete. After it had set properly, I slurry-coated the entire staircase. It turned out great.
Good thread!
How's it going Akhe? Have you fixed the stairs? If you've gone ahead, I'm very interested in the method, experiences, and results.
I'm hijacking the thread here and posting pictures of my stairs. At the same time, I'm wondering if anyone has suggestions on how I should fix my stairs. There are very nice granite slabs on crumbled concrete.
Per.
How's it going Akhe? Have you fixed the stairs? If you've gone ahead, I'm very interested in the method, experiences, and results.
I'm hijacking the thread here and posting pictures of my stairs. At the same time, I'm wondering if anyone has suggestions on how I should fix my stairs. There are very nice granite slabs on crumbled concrete.
Per.
Where did the response about duracoat and duratrapp go? I received information about a new post in my email just now but can't find it here in the thread?