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How to extend concrete patio on uneven land...
When building a patio one has a tendency to get in a hurry and not get the base of the patio compacted evenly. If the base is not compacted evenly, the stones will settle differently and therefore, after a few years you may find areas of your patio that have settled more than others. This settling can also happen in areas of heavy traffic. This can cause pooling of water on the stones and may cause someone to slip or trip on the uneven areas.
Build a patio with your own DIY patio blocks made of soil cement