Bath Vent Through Top Course Of Cmu Wall?

bob_cntrctr

Gentlemen,

New bath fan in an old house with cmu walls. Bathroom's on an exterior wall, making placement real neat - ceiling mount right close to the outside wall with the exhaust pointing toward the wall - a nice short, straight, exhaust.

BUT - there are no soffits, think 'open eaves'. So an in-the-ceiling intallation with soffit vent is out.

So I'm looking at a dropped ceiling over the toilet, then out the cmu - but that would put the 4" vent pipe hole in the top course of the 8" cmu. I'm wondering about that last bit - 4" hole in the top course - seems to me like it might promote cracking. Maybe if at least it's not directly under a truss?

Thanks.

We Fix Houses

Your method is done everyday unless there's something your not mentioning. Stay between the bearing forces of the roof above. The cores of the bearing area may be solid filled but I doubt it. A 5" hole through the outside wall is not a problem.