Hi,

We’re doing a major remodel on a 3 story + basement, 20-unit apt building. There are 3 interior corridors that are completely enclosed (no outside wall).

Code here in Oregon says corridors should be ventilated @ .05 cfm / cu ft. But the building was built in 1900 without ventilation, so the requirement does not apply (existing condition).

My problem is that if we don’t ventilate, there might be stale air or odors; but if we do ventilate, the cold winter air may cause condensation and possibly mold growth, not to mention it will make the hallways uncomfortably cold.

You’re going to say, heat the air. We looked at electric duct heaters, which are relatively simple to install but are ugly and would cost some $2,500 a year to operate. We looked at a central air furnace but the ducting would be extremely problematic to install because hardly anything stacks from floor to floor in our 1900-vintage framing, and 1-hr corridors intersected by a 2-hr stairwell shaft make penetrations highly problematic.

So here is my question. In your opinion which of the following is best:

1. Ventilate as per code (.05 cfm / cu ft, or 3 air changes per hour) and take a chance w/condensation and mold;

2. Ventilate minimally (.015 or .2 cfm / cu ft) in the hope that condensation and mold would no longer be an issue due to the small amount of outside air supplied, while still providing roughly one air change per hour. Maybe in conjunction with an air purifier.

3. Leave as is (no ventilation)

What do you think? Your feedback is appreciated.

Thanks, Frederic