I am attaching a plastic bathroom exhaust fan vent (like a dryer vent) to an aluminum soffit. Should I use long enough screws to go thru aluminum soffit panel and into the old wood soffit above or would just using small sheet metal screws to attach it to the aluminum only be sufficient? I prefer to do the later but what is the best method? p.s. if it makes a difference the vent is attached to the duct with tape and a clamp.

I have some rotted T1-11 siding I need to repair. I am thinking about repairing the rotted T1-11, putting house wrap then Hardi Lap Siding. I have some question. 1) Looking at the photo below you can see the bottom of the T1-11 is rotted. [url=http://screencast.com/t/r2csJEHCvdb2]02.27.2016-11.07.21 - Bobby1002's library[/url] I could cut out the bottom 16” or so, Z Flash and install new T1-11, but I was thinking it would be better to cut out the rotted T1-11, install blocking and install Pressure Treated Plywood in the damaged area and patch the T1-11 and Plywood butt joint. My thinking being near the bottom if water splashes up or weeds grow up the Pressure treated plywood would not rot like the T1-11. So it will look like the photo below: [url=http://screencast.com/t/hXnvpG8UpYnT]02.27.2016-10.56.44 - Bobby1002's library[/url] If I go this route my question is the T1-11 is 5/8”. I am still looking to find a local place that sells 5/8” Thick PT plywood. Does this option seem the best way to go. 2) The 2 roofs intersect on both sides where I will be installing the Hardi Lap Siding as shown in the photo below. As you can see they used T1-11 with z flashing. I am thinking on the roof sloping down I would use either L or step flashing and some type of rain diverter at the end to direct the water away from where the facial would hit my new Hardi plank. I would caulk between the Hardi and the Facial, which seems like a leak potential. I circled the ares in green. I am not sure how to best side this location. Any suggestions? [url=http://screencast.com/t/hyMZCWUg9lwH]02.27.2016-11.22.15 - Bobby1002's library[/url] 3) Between the Studs and the original T1-11 Siding is felt paper as a WRB. Is adding house wrap between the T1-11 and the Hardi going to be an issue? 4) Flashing around the windows and door. I am not sure how you can do a perfect leak proof flashing without removing the T1-11 and windows, which I am not going to do. I am thinking about running the house wrap right up to the window and then run Flashing tape against the window edge and over the house wrap. Then install the window 1x4 trim, top header and then Hardi.