Projectiles going through floor only

Built a map in unreal editor. Used default floor (mesh) and blocked it out with bsp geometry. Both in rendered game and playing in editor, projectiles go through my floor. They hit all other bsp objects no problem. Even non projectiles such as enforcer, sniper, and link secondary hit the floor. Rockets, flak, goo do not, they go through. Tried blocking volume, no success. Tried replacing entire mesh floor with bsp and still no success. Read a ton on the internet and have implemented “fixes” but no success. Really need some help. Once I solve this I can begin to texture it. The map is an Elimination map for unreal tournament.
thanks
Mondogrunday