Humber has Lakeshore Campus where we contract it all out. Our North Campus, however, we contract out the roadways and parking lots, while doing the walkways inhouse. Because of this I can easily compare the costs of the 2 models, and it is very similar.
In house give us better control of the quality, which is particularly important for the walkways. But there is also more risk because I don’t have 24/7 coverage, and what happens if one of the 4 guys gets sick.
Overall, I’d probably tend towards contracting out the entire thing, if I was starting from scratch.