In this video this old house general contractor tom silva shows how to properly install a roof mounted bath fan vent.
Venting bathroom fan through roof.
Options for venting a bathroom exhaust fan include best to worst.
Choice is go up to roof 5 6 feet or out the present vent 15 18 feet with insulated pipe or shorten the line by going straight to side of home but this requires going up high with latter to drill a new vent hole as tight quarters in attic prevent drilling from attic.
Through the roof or an exterior gable wall.
Behind a soffit vent.
In order to accomplish this the roof has to have a hole cut in it.
From inside the attic drive a nail through the roof directly above the bathroom vent fan.
No need for special tool.
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Leave the drill bit sticking through the roof so you can find the hole.
Try to keep it close to the fan location.
Going to the soffet is 12 feet.
From the roof find the nail and use the utility knife to cut roof shingles from around the nail.
Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.
This involves running ductwork from the fan usually though an attic and out through the roof.
Center the nail between two rafters.
From up on the roof use a jigsaw or reciprocating saw to cut a 4 in.
It is because of this that many builders tend to advise against this method.
This old house general contractor tom silva shows how to properly install a roof mounted bath fan vent.