I have a quick question about my collar ties that are located on each rafter in my cape cod 1.5 story attic. The collar ties (1.5 in by 5 in) are positioned at 7.5 feet high ( at the bottom of each collar tie) with the apex of roof at 10 foot. The rafters are 2x6 and go all the way down to the eaves. Are these collar ties structural or can I take them out or at very least every other one? Even after taking out every other one I would still have them about every 2.5 feet. Currently they are spaced a tad over a feet apart. Reason I want to remove some or all is that I have flashed and batted the underside of the rafters and want to do a cathedral ceiling.