I asked Timbo about it...
[16:25:19] <OverFlow> and if I cover an area with a 'no build' covered brush... no one should be able to build inside correct?
[16:26:05] <Timbo> ....may....... be....
[16:26:28] <OverFlow> cause it doesnt seem to <.<
[16:27:19] <Timbo> are you using custinfoparms and all that crap?
[16:27:36] <OverFlow> eh?
[16:27:51] <OverFlow> common-trem/nobuild
[16:28:10] <Timbo> yeah, but you need to build with a custinfoparms thingy too
[16:28:17] <OverFlow>

[16:28:19] <Timbo> unless you use a patched q3map
[16:28:23] <OverFlow> nope
so I have no idea what anything he says means... anybody help? <.<