Oh do please have another think and plant something else. We are plagued with these wretched confers by neighbours who let them get out of control. They grow at a rate of between 3 and 6 feet every year, and unless you have the time, the appropriate ladders and some expensive electric hedge trimming equipment you will find that despite your well meaning intentions, within 12 months they will have grown out of control and you'll be paying several hundred pounds a time for tree surgeons to come and do the job for you.
Also, the depete the soil massively around the roots, whether in your garden or your neighbour's garden so that nothing will grow, not even grass. If you want privacy, a much more wildlife friendly barrier would be a hedge of mixed shrubbery like hawthorn, wild roses, or even beech.