Wheel Tire Height Change: 27Plus to 29 All, 

I have a 2017 Scott Spark 720. It has 27.5 Plus Tires on it 2.8 maxis recon which I run at 16/18 psi (amazing traction).

I have been getting a lot of pedal strikes (In rocky/rooted turns, mild but annoying and throwing me off line) and have been considering purchasing a 29 inch wheel set to put 2.6 tires on it. I estimate that I would be running closer to 25 psi in them.

Approximately, how much would this increase my BB height by? I think if I could get 1-3 cm increase the pedal strikes would pretty much disappear.
The difference between 622mm rims on 29” wheels and 584mm on 27.5” wheels is only 19mm - about 3/4 if an inch. If you run a narrower tire the rim plus tire diameter different is even less. 

In general bike frames do not have clearance for larger wheels so this may not even be possible. 

Note that larger wheels will also change your steering geometry.