I recently switched to natural gas heat, and in doing so found out the hard way (via CO alarms) that my chimney isn't drafting properly. After numerous inspections and experiments, it seems the culprit is the power vent in the attic. When it turns on, it essentially sucks air through the house and down the chimney, causing the boiler to spill exhaust right into the basement. I have already installed a powered fresh air supply (Fan in a Can, it's called) next to the boiler, so my next step is to address the attic ventilation situation. I don't want to simply turn off the fan and the leave the attic as is... it surely needs some ventilation. So the question is, what do I do? For reference, the roof in that area is square with a peak in the center, so there is no place for a ridge vent. The power vent is about halfway up the side of the roof. My initial thought was to install soffit vents around the perimeter (3 of the 4 sides) and see if that provides enough air flow for the power vent, but that would be a lot of money down the toilet if it didn't work (I wouldn't be able to do that myself). My next thought was to replace the power vent with a standard square vent, then add the soffits and maybe another square vent on another side of the roof. I am thoroughly confused, as you can tell. Any suggestions?

I am doing a 8' x 12' pergola over my master bedroom decking attached to ledger board at house. I plan on a 2/12 pitch, just enough for rain run-off. I need to cut my rafter with a slant to get the pitch. How much of the wood do I cut at a slant to get a 2/12 pitch? Thanks for all your good information here!