Thought on this vent system

Sorry no pictures for this but I walk into the garage there is a 24 inch updraft vent fan in the ceiling of the attached 2 car garage. The roof is gable with end vents and clay tile.
The fan is thermostatically controlled.

So the question is? any other faults besides the negation of the fire rating for the garage, drawing combustion fumes into the attic, and the negative pressure created in the garage when the door is closed?

Other than a possible breach in the fire wall, I would also be very concerned about CO finding it’s way into the home.

Needs to be vented out the sidewall or removed.(Period)!

Not necessarily true Bob. :smiley:

Firewall issue.

Was there a damper on the opening? Sometimes they have normally open contacts that are hooked up to the smokes. When the smokes go into trouble, the damper automatically closes.


Currently as described I would agree it is a Firewall issue…

Call out the defect and move on…

There may be many ways to correct the situation, and it is up to the Client as to how this work is done.

For a HI to tell anyone that there is one way to correct this is not very clever.

Of course some of the 4 hours inspectors just do not know when to keep quiet…:wink: Hence the long draaaaaaaaaaaawn out inspections…:smiley:

Was the area above the fan able to be viewed? If so, does the vertical portion of the vertical/wall firewall extend up to the roof? I mention this to rule out whether the d/wall on the ceiling was added after original construction.

All things equal… there may be 2 issues here. But simply put, if you can’t see the firewall extend and properly divide the living space and the garage you should call it out, whether it’s that the fan violates the integrity of the firewall OR that you can’t see/confirm the firewall, this is up to you as you were there. Basic firewall construction and protection is just that … basic.

The fan/pressurization issue is another one entirely… fuel burning appliances and so on.

Speaking of Dry-Walled garage ceilings

I see a fair amount of Dry-walled garages that originally were just a firewall that extended up into the trusses or roof framing and unfinished studs and walls, kinda like an unseedy club. Well, many times the drywall is put on after the fact by a less than knowledgeable contractor or a Home Owner and creates an area with NO ventilation, just Damp Framing :slight_smile: Then a few years later, Saggy Framing. If you haven’t seen the movie Soggy Framing Boys by the COHN Brothers… it’s a goodie BTW.

There was no attempt here to comply with ANY codes or safety issues. There was no fusible link automatic closing fire damper, it vents directly into the attic that has a straight shot through the entire attic. no vents in the garage walls or door. The register on the face of the fan was not even like the old whole house fans that opened upon operation.
I think this was installed by the AC guy to prevent condensate buildup on the air handler located in the attic, by reducing the attic temp.

…and your alternatives ?.or are you just spouting till someone else answers for you.:smiley:

drawing fumes into the attic should be a concern on the account if there is no fireproofing in the attic if attached to the house. if the two attics are not sperated then yes major concern. if detached other than neg pressure the venting should be able to disharge the fumes created by stored chemicals/gasoline etc. my question is why the vent. is this client a painter and using the garage as a spray booth? look around for clues that might help to understand why it is there. and then make your notes into the report you create. this is my opinion but take it for whats its worth for i’m new into home inspecting but have a variety of construction background

Bob, I can think of a number of ways to correct the defect. :wink:

But telling a Client that “The only way” to fix something is “This” is asking for trouble, IMO.

You will get someone who comes along after you that will say something else, and in this case they will be right. :smiley:

OK name one.:twisted:

They could stick the vent Up your a sssss :twisted: :mrgreen: :mrgreen: