That and you can back into the garage if you want.
And no oil/fluid leaks on the garage floor.

It’s a larger garage, and I am installing it primarily for IAQ improvement (PM dilution) because of my activities in the garage. For now, blowing dust on my neighbors will have to do, before I spend more on noisy filtration systems. Yes, I do have dust removal while I am working in the garage, but there is always plenty of residual floating around and by running the exhaust fan overnight, I am hoping to remedy that. Should I run a CONTAM simulation for that? Probably. But I am just going by my instinct here.

Given the right conditions, there may be days here in our Atlanta climate when the garage will be colder, especially in the first half of the day, and may in fact be below exterior dew point. Those days would be to watch our for.

But the Intl Mechanical Code has a solution for CO buildup in section 403.3. This requires 100 cfm of continuous (exhaust) ventilation per bay in residential attached garages.

In my 20 years experience testing garages, the IMC spec is good enough to a) lower pressure in garage relative to attached house and b) remove all toxic air pollutants from the garage to outdoors so they never reach dangerous levels in garage or home even if a vehicle is left idling. Most garage doors are so leaky there is no need to provide any air intakes. (Controllers that only run exhaust fans for up to 2 hours after garage door opens are not sufficient to prevent deaths from CO if the source is an idling vehicle. Engine may be started by child pressing key fob in kitchen without anyone ever opening garage door. )

I recommend installing bathroom fans with low sone ratings for this application as they can’t be heard from adjacent rooms. They cost under $200 retail and less than $25/year to run. The greater expenses are installing them through an exterior wall and running wiring to code.

Allison…THANK YOU for the quick reply…I appreciate your advice and thoughts. I could have never imagined any odor lasting so long. The wall is marginally better after a year but still has some odor. I even tried a Hydroxyl generator last summer. I did look into an exhaust fan, but have to break a hole in the brick wall on one of the garage side walls. But it’s on the list of options as I know air exchange is one of the best things you can do. In the summary my garage is so humid you can feel the water on the wall. I need to also look into a dehumidified. I think I’ll give it a few more months while trying to improve circulation, as sounds like you agree with my concerns that adding a membrane may result in other issues. I did enjoy your article on preventing my garage from making me sick…it’s been my life the past year!

Steve: I can’t imagine that the drywall is going to keep offgassing for a long time since that’s a secondary source. Rather than try to use membranes or coatings on the drywall, I’d recommend installing an exhaust fan in the garage. Run it continuously as long as necessary and then put it on a controller like the GarageVent, which I wrote about here:

Another Way to Prevent Your Garage from Making You Sick

I got sort of a attached garage / air barrier issue maybe you can provide some advice on if you have a min. Last year I had a polyaspartic (epoxy like) floor applied, but the contractor mixed the chemicals wrong which resulted in a horrendous odor that would not dissipate, even with the garage door open constantly for one month with fans. Also leaked into my house. Another contractor mechanically grinded the floor off, and re applied. Floor is good now, but the painted drywall absorbed the original odor and no matter how much I air out (over a year) or paint over, still have the odor.

My question…I found some sealers that I can apply to the walls which create a membrane to seal in odors, sort of like shellac, but more chemically sensitive. But concerned if I apply this over the drywall and ceiling I’ll in effect create an air / vapor barrier between the garage (no heat or no ac) and house (back wall and ceiling) and side exterior walls, which may cause moisture / mold issues in the walls.

Not sure if this in effect would be similar to an air barrier, but any thoughts / suggestions would be greatly appreciated! I live in New York.

THANKS!!!

Steve

Alexander: Yeah, you could do both, but in addition to cost, it adds complexity.