can't seem to get func_physbox to cast shadows properly in a room

[[Maxx]]

im making a map with tornadoes in it and one of the buildings is a trailer park-type area
it has this one building where the roof is just sliced into 8 physbox entities, and i can't seem to get it to block the sun properly.
[IMG]http://images.akamai.steamusercontent.com/ugc/353895563090602798/D3607B96492025DD0CC0F4731B58AEA9B412CCBF/[/IMG]
normally, the light inside the building would just illuminate the area rather than the sunlight, and it would be able to be turned on and off
but for some reason it doesn't prevent light from passing through, it acts as if the roof isnt even there
what can i do to fix this?

[Firegod522]

Because the older version of source your using doesn't support dynamic lighting very well, other than the flashlight projected from you face, it has to pre-bake the lighting into the map, and it ignores most brush objects like func_brush and what not.

I believe a way to solve this error is just to put a brush with the blocklight texture inside the ceiling brush, can be inside the brush itself, so that way it tells the compiler not to cast light through it, because it is a ceiling.