The Physical Effects of Explosions on Porosity

In my machinima documentary, I used fraps to capture images and videos clips.Every clips shows some part of crysis environment with different type of explosions of entities.
Different time of the say setting was very easy to use and also interesting.
I used grenade to explode the buildings in environment but the thing was, you have to be very close to the building so you can throw the grenade, and some building did not explode with grenade. I also use Vegas movie editor to edit my clips taken with fraps from the crysis environment.