Lightmap help

Hi again, I seem to have gotten around the weird shadows, even with lower lightmap resolution, but I cant seem to get rid of the light seeping through the roof/top of the walls…
This is built with only one specific mesh:

http://puu.sh/gHqZR/e8ab856dfa.jpg

And the lightmap looks very simple and padded, or am I wrong?

http://puu.sh/gHr1J/d6532945c7.png