You better make sure your insurance will cover you since you're gonna be higher than two steps on a step ladder. Besides, when obtaining the permit to do such work.... as you put it 'That High' you'll need to show proof of probably at least 2 or 3 million worth of liability insurance . If you go up there and don't hurt yourself, can you imagine the damage you could do if a drill or hammer falls, let alone if you step back to admire your own work ??