Ventilation Information
Yesterday I installed the housing and vent for my new bath fan. Everything went pretty smoothly. I drilled a hole through the old access hatch that used to go up onto the roof. I figured that might have a few less layers of built-up roof on it. It also had a coupe layers for sheet metal flashing, but nothing too difficult for my new DeWalt tools! ha ha!
My new fancy roof cap went on beatifully. I picked it up last thrusday out in Halethorpe at US&D, a HVAC supply place. When I went in and asked for the part the two guys there looked at each other and and scratched their heads. "Flat roof? You need it for a flat roof?" Apparently I'm the only person in Baltimore who doesn't have a pitched roof. At least the only one who wants a bath fan. After a while they did find finally find the flashing I needed. Maybe I should have just gone with the wall vent. Ugh.
After I installed it, I noticed that the metal housing for this thing is totally covered in little holes. Holes for screws, nails, knockouts for the electrical. Now I have to figure out how to cover this things so that it doesn't spew moist bathroom air into my attic and grow mold everywhere.
So I started to do a little research and realized I did a lot of stuff wrong. First off, I need to use foil tape or duct mastic to connect the vent duct instead of regular old duct tape. I kind of knew this already but since home Depot didn't seem to be selling the stuff, I wasn't worried. But regular duct tape, or even industrial strength duct tape is going to get old and crumbled after a while. Yet again, Home Depot doesn't know crap.
The bigger problem is my 4" pipe reduced to a 3" pipe which impedes the ventilation and then to make matters worse, there is a 90" bend right at the fan. Panasonic recommend against all of these things.
Fortunately the duct is really short and my bathroom is really small so this might not be a problem. The fan is rated at 80 CFM and I only need probably 50 CFM. Basically, I'm going to have to hook this thing up and test it to see how well it works.
It's my own fault. I should have just stuck with the wall vent I ordered. I wouldn't be having any of these problems if I had done that. All because I didn't want to ugly up the back of my house.
Will it work good enough? Am I too anal? Can too much information be a bad thing?!