Thanks for your input , pretty much raising concerns that I thought might occur so shows i'm at least thinking along the right lines .
@SantoToribio : Yup the buildings have core meshes since that video, so you can still destroy the pillars but a frame remains in place.
@Carsten: Yeah thats true lol. This has been sorted so that during the play testing the rocket launcher wont damage the environment. Im scripting my own weapon and only that will be able to destroy the buildings, and only 4 or so of these will be available to each team over the game. Hopefully this is make teams co-ordinate their hole-in-wall blowing ability