A deck can be built around a pool even if the ground around the pool is uneven, sloped or has a retaining wall nearby. The first and second row of blocks can be placed at different levels, and the posts are braced to each other, as the following photograph illustrates. One of the main concerns is making sure that the blocks are firmly planted, tamped and upright.  View the Frank and Adele Deck Project to see an example of building on sloped ground.