Dear forum members,
I am new here and hope to get some good advice from you to successfully complete my current project.
It involves renewing an old terrace. I have several questions, but I will post them in separate threads so that the answers can hopefully be helpful to others as well.
Currently, there are paving slabs laid on sand over a concrete foundation. I want to extend the concrete foundation by 65cm (25.6 inches). The question is whether I could use the existing sand for mixing concrete. Normally, one would either use ready-mix concrete or mix cement with concrete aggregate (1:4), but I thought that by reusing the sand, which otherwise would need to be disposed of, I could kill two birds with one stone. This would save effort and costs. As far as I understand, cement mixed with sand only is less load-bearing, but I think in this case it may not matter much. On the other hand, I don’t want to do a poor job.
The sand is not mixed with soil since it lies directly on the foundation slab.
What is your recommendation on this topic?
Best regards, Pivi
I am new here and hope to get some good advice from you to successfully complete my current project.
It involves renewing an old terrace. I have several questions, but I will post them in separate threads so that the answers can hopefully be helpful to others as well.
Currently, there are paving slabs laid on sand over a concrete foundation. I want to extend the concrete foundation by 65cm (25.6 inches). The question is whether I could use the existing sand for mixing concrete. Normally, one would either use ready-mix concrete or mix cement with concrete aggregate (1:4), but I thought that by reusing the sand, which otherwise would need to be disposed of, I could kill two birds with one stone. This would save effort and costs. As far as I understand, cement mixed with sand only is less load-bearing, but I think in this case it may not matter much. On the other hand, I don’t want to do a poor job.
The sand is not mixed with soil since it lies directly on the foundation slab.
What is your recommendation on this topic?
Best regards, Pivi
W
WilderSueden9 Aug 2023 21:33The smaller the grain size, the less stable the concrete will be. Using sand will produce more of a mortar with correspondingly lower load-bearing capacity. A professional wouldn’t do this, but an amateur can obviously cut corners as they please. For a few garden chairs, it’s probably enough, but two trailers of gravel aren’t that expensive.
WilderSueden schrieb:
The finer the aggregate, the less stable the concrete will be. Using sand results more in mortar, which has correspondingly lower load-bearing capacity. A professional wouldn’t do this, but as an amateur, you can obviously cut corners as you please. For a few garden chairs, it might be sufficient, and two trailer loads of gravel aren’t that expensive anyway. It’s more the effort than the cost. However, I see both previous answers point in the same direction, so I’ll get rid of it. Thanks in advance!
Pivi2000 schrieb:
I am new here and hope to get some good advice from you so that I can successfully complete my current project.
It is about renovating an old terrace. I have several questions related to this, but I will post them in separate threads so that the answers will hopefully be useful to others as well. Sorry, I had to help a friend finish his birthday cake last week, otherwise I would have responded to you immediately: if your project discussion is meant to be helpful for others (and not least for yourself), then do NOT scatter it across fragmented threads where it becomes maddening to keep the facts clear!
It’s best to close the offshoot threads, but not without linking back here.
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