installing bath vent fan into old house
alexpesta
| Posted in Construction Techniques on
Anyone know the best way to install a bathroom vent fan into an old brick house? I was thinking about routing the duct into the attic, turning down and venting out of the soffit. However, I am concerned about condensation (living in Cleveland) at the turn down at the soffit. Any suggestions?
Replies
Can you go through the roof? Probably a better choice.
What you say will work, but it takes a little extra care. Use seamless duct as much as possible, slope it towards the outside slightly, and insulate it. Consider adding a secondary flapper above the fan unit, to minimize air leakage when the fan is off.
You'll have to hunt around to find a vent outlet to go under the soffit (you want something to keep the birds out, plus it's good to have something with a flapper), but these units can be had. Don't use a unit designed for a wall.
I think DanH is right -- seamless ductwork (pitched down slightly), covered with fiberglass pipe insulation all the way back into the house. Use a cap with flapper.
I used this technique on my own brick house for two different second floor bathrooms. The set-up has been used now for about 12 years with no problems.
The biggest problem was getting through the 12 inches of wall (3 layers of brick). I tried a hole saw, and finally gave up. Instead used an SDS drill to make 1/2"holes around the 4" hole's diameter, and then broke it out with a cold chisel. All of this was above the soffit, so is not visible. Filled the rough edges of the hole with mortar.