Look at this halfs walls I found @ MTS
:
http://www.modthesims.info/download.php?t=380720Description
Why? WHY!? Why did EA leave this out of the game? This has frustrated me since day one of The Sims 3, if you want something done right, you have to do it yourself, so that's exactly what I did, and of course shared with you guys . The half wall acts like an ordinary fence in The Sims 3, it is a fully Castable fence, so you will need to latest patches for your game if you don't own World Adventures (but please note: World Adventures is NOT required for this). The railing and wall itself are two seperate recolorable parts so you can make it match virtually any existing wall you have. It is also great with counters, it fits all the game ones perfectly so there is no chopping on anything of that nature . I guess that's all I need to tell you, enjoy!