I need to install a 4" dryer vent thru my floor of my laundry room.The reason for going thru thr floor is because the room is in the middle of the house and there's no exterior wall in the room. It will go into the crawl space and out through the closes wall.My question is after I cut my 4 1/8" hole through the floor, what do I put through the hole and how is it attached? I can't seem to find any duct piece made for this.

Hi Jettyspicer

There really isn't any "special" thing we do with these... ;) Here, we usually just cut the hole and hang the dryer vent every few feet and run it so it pitches toward the outside at all times. For long runs, I would also recommend that you install a cleanout tee with a cap every 20 feet or so, so you can clean the vent periodically, OK?

If you want to get real fancy, they do make a concealed through the floor dryer kit. It gets installed in the wall and is expensive, but they do make it... see image.

Finally, if you want to get a flanged duct piece I'm sure a local sheet metal fabrication shop will make one up for you pretty darn cheap!

Back to you...

Mark

Mark gave you good detail. I only use 4" metal duct, galvanized. Snaps together. You will need a 90 degree ell through the floor and another ell to change direction so you can vent it out a wall. Keep the pipe as short as possible, give it a slight drop so any condensed water flows out and be sure to install a wall cap. I would also install a collar around the floor opening to keep "things" from crawling in.