raising roof

I just had a client call in a change on a project thats nearly done....(#%#!!!) wanting to raise all walls from 9 ft to 12 ft..

I had no trouble increasing wall heights in elevation view.. but cannot seem to raise the roof to match.. I have deleted and redone the roof.. tried the transform-replicate object and the z-plane.. .. its not the effect I needed ..I realize now that this raises and lowers planes and not the roof proper( from what I gather)
The reference manual on page 307 shows a 'change roof pitch or height.'. saying it will appear when you"attempt to snap the corner or edge of a roof plane near the edge of another roof plane whcih does not match vertically"..
My roof is a single level gables 6/12 with several wall bump-outs and gables above each.. and has no other plane vertically..
I m sure this is something where I cant see the trees for the forest.. but cant seem to find anything in the threads, or help
data base.. etc
appreciate any suggestions..
thanks all..
Randy

To raise the roof I use transform replicate on all of them, or for each roof plane lock the roof pitch and raise the baseline height.

Jason.. thanks.. it worked good..
I m not totaly sure why it didnt work the first couple of times I tried it.. ( I had not done that before)..using the tranform replicate..
anyway.. as we say around here.." doubtless a great mystery is solved..."

thanks again bye

Randy ...

I've had good luck by selecting the roof planes in plan view and go straight to the replicate tool. No locking anything.

Another thing that helos me with roofs is creating a layer set that has nothing but roofs and walls.