This is one of the most common mistakes we see from people who are not experienced with air ducts.
Is my dryer vent on the roof.
Most people don t have such a ladder.
Next you must access the inside of the vent on the outside of your house.
The vent was on the front of the house directly over the third floor laundry room.
It should go out through a wall or the eve of a roof.
Remove the guard to the dryer vent on the roof.
And to access it from the rear a 40 ladder would be needed.
In my humble opinion dryer vent terminals should be accessible from the ground if you already have a home with a dryer that terminates at the roof be sure to have the terminal cleaned on a regular basis and consider having the terminal replaced with a dryerjack terminal.
Get the extra clearance model 486.
You might find that there are gobs of lint stuck on in.
You can remove some of this with your hands.
The new dryerjack is the most efficient.
Trust me you don t want to do that.
To access it from the front a ladder would have to have been placed on the metal front porch roof.
In fact if it is not easily accessible you are probably better off simply hiring a professional.
Considering that back pressure higher than 6 wci is generally recognized as inefficient you can see that venting through the roof with non dryer specific vents is immediately problematic.
If it is on your roof this can be a tricky step.
When you get on the roof you should find that the vent is covered by a guard.
If you can access the vent from a ladder safely detach the vent cover by unscrewing it and using your knife to remove the caulk.
It is not advisable to vent a dryer through the roof.
If you can remove it.
Dryer vent specialists will tell you that a vertical approach to installing a dryer vent is inefficient and creates a fire risk for a home if it goes unchecked.