It is not so much that the roots are on a seek and destroy mission as they are opportunistic. Roots flourish where there is moisture, and you can see how well they did when the drains provided it. If you plant a big tree close to your drains they will take advantage of leaks, and wet spots. Cedars are thirsty plants, you can't blame them, it's a case where hedging was a bad option. If your property line is close to the house sometimes a fence is your best privacy option.
In our area, houses can be as close as 5 ' off the property line, now that is very close, but resist the urge to plant a hedge along this side of your property. In the case of the Western cedars you will have the added problem of plant side. This tree wants to be BIG, even with regular shearing it will encroach on your walkway. We have seen what happens underground, it's not much better above, and you may have created the same problem for your neighbour.
Cedars are beautiful hedge plants, fast and easy to grow, but often a terrible choice for the urban lot. When you choose a hedging material always consider maintenance, size of mature plants, and things like other plantings, and hardscaping. You may find the area at the foot of a hedge very hard to plant, leave ample room for beds. The foot of a cedar hedge will be dense with roots, and very dry without irrigation. They may also need to be pruned 2-3 times a year to keep them in check. You can save yourself a lot of money and heartache choosing the right planting .
Cedars are beautiful hedge plants, fast and easy to grow, but often a terrible choice for the urban lot. When you choose a hedging material always consider maintenance, size of mature plants, and things like other plantings, and hardscaping. You may find the area at the foot of a hedge very hard to plant, leave ample room for beds. The foot of a cedar hedge will be dense with roots, and very dry without irrigation. They may also need to be pruned 2-3 times a year to keep them in check. You can save yourself a lot of money and heartache choosing the right planting .