I am building a new house and getting ready for the siding. The hose bibs, electric boxes and dryer vent have all be located and plumbed or wired but
I haven’t mounted the boxes on the 1/2″ osb wall sheathing. 

Contractors are all mounting the hose bibs dryer vents on a block and then
installing Hardie plank around them. 

Is there a better way to mount these utilities? I’ve seen the blocks crack after
a few years. What about using 1x material instead of 2x material?  

Thanks 
Rick