I am installing a mini washer/dryer into a second story bathroom. I want it to be the safest and easiest installation that I can do myself. I understand the basics: minimum 4" diameter tube. Use hard tubing not flexitube, No more than 25' and subtract 2.5' for each 90 deg bend, etc... But here are a couple questions about doing it right in my particular situation.
Most dryer venting systems are attached to the wall. In my case, there is already a conduit under the floor where I am laying pipe. The conduit is between a major beam and a 12" floor plank which will be under the bathroom floor. I want to run my dryer vent in that conduit. But access to the conduit will be on the floor. Can you do that?
The venting pipe will go into the garage attic, make a 90 deg bend and then go 10' to the nearest outside wall. The outside wall happens to be above the garage roof. The vent will exit on the second story about 2' above the surface of the garage roof. Is this acceptable? ( I see other cases where people vent dryers onto their roofs. I don't know if its a good practice.)