I am finishing basement and have finished the rough-in for the new plumbing. Now i need to connect to existing house plumbing. I have located an accessible location to tee in my 3/4 hot and cold water lines into the 3/4 exisiting lines. But I am having second thoughts before I cut into the existing lines since I cannot determine whether I will have enough play in the existing lines to push aside to get my 3/4 tee in place. I would have to remove a large part of the ceiling to see if I have any play. Any suggestions??