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 2×6 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.