Thread: Bath exhaust fans Interesting discovery

Hi all,
This is actually my first post, even though I have been reading this forum and all your posts for quite some time. I must say, I have enjoyed reading all the posts and comments and have picked up a few things along the way that have benefited me as a home inspector. There certainly is a lot of you with many, many years of experience out there.
I came across something interesting today. First, the main bath & the master bath ventilation exhaust fans were tied in to the same duct. I think I've read that this is against current code. Is that correct? However, the more interesting thing was they were also both wired together. THAT I have never seen. When you turn on the switch for the main bath fan, that fan & the master bath both come on. Same thing happens when you flip the switch in the master. Has anyone come across this, and is there some code that says this is a problem. Its weird, and would be very annoying, but Is this a safety issue?
Thanks,
Rob

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I don't believe it violates any code. Are you sure there were two fans, or were both bathrooms ducted to a single fan in the attic? This is sometimes done with inline fans like the type used for Radon mitigation systems.

Originally Posted by Mark Reinmiller

I don't believe it violates any code. Are you sure there were two fans, or were both bathrooms ducted to a single fan in the attic? This is sometimes done with inline fans like the type used for Radon mitigation systems.

Thanks for the reply Mark. There are definitely two separate fans. very odd.

Originally Posted by Mark Reinmiller

I don't believe it violates any code. Are you sure there were two fans, or were both bathrooms ducted to a single fan in the attic? This is sometimes done with inline fans like the type used for Radon mitigation systems.

Mechanical code says air exhausted from bathrooms shall not be recirculated. (Means they can't be tied together!) But if both fans are turned on at same time, this might get past the code problem? Never seen this before.

Originally Posted by Vern Heiler

Mechanical code says air exhausted from bathrooms shall not be recirculated. (Means they can't be tied together!) But if both fans are turned on at same time, this might get past the code problem? Never seen this before.

Thanks Vern, that's what I was thinking, about them being ducted together, but still amused by them both wired together. That is an interesting thought that both always turning on together may get around code. Of course that may not have been the code in 1991 ?
How annoying that is going to be for the new buyers. I'll definitely note it in report, but I sure can't give a reason as to why.

Originally Posted by Mark Reinmiller

I don't believe it violates any code. Are you sure there were two fans, or were both bathrooms ducted to a single fan in the attic? This is sometimes done with inline fans like the type used for Radon mitigation systems.

I was hoping for a reply to Mark's comment about having a common fan in the attic or on the roof (in the attic is more likely for a house).

That would certainly explain both coming on at the same time.

Two separate fans being ducted together and switched on at the same time? I suspect that would not pass the smell test (pun intended) for meeting the code as one fan could fail or not turn on for a variety of reasons.

Like Mark, I am thinking it is a common fan in the attic.

And, yes, that common fan in the attic would require access to it, so you should have been able to both see it and access it.

Originally Posted by Jerry Peck

I was hoping for a reply to Mark's comment about having a common fan in the attic or on the roof (in the attic is more likely for a house).

That would certainly explain both coming on at the same time.

Two separate fans being ducted together and switched on at the same time? I suspect that would not pass the smell test (pun intended) for meeting the code as one fan could fail or not turn on for a variety of reasons.

Like Mark, I am thinking it is a common fan in the attic.

And, yes, that common fan in the attic would require access to it, so you should have been able to both see it and access it.

Thanks for replying Jerry,
I guess I can't say for sure because I could not safety get to the back of the house where the bathrooms were. I tried twice. After I could not find any venting to the exterior, I went back in the attic to try again. The access was up front in the garage and with the vaulted ceilings , weird roof lines, and high quantity of insulation I was having trouble not falling through the ceiling. Normally I can get to a good portion of an attic by being a monkey and crawling through trusses. The reason I felt it was two fans is when you look up into the actual shroud attached to the drywall you see the fins on the fan motor turning. I hate not being able to access a section of a house, especially when there is a possible issue, but getting hurt or damaging the insulation and sheet rock is not a great way to end your day either.
What might you have done in this situation?
Thanks again,
Rob

Originally Posted by Spearhead Inspections

After I could not find any venting to the exterior, I went back in the attic to try again.
.
.
The reason I felt it was two fans is when you look up into the actual shroud attached to the drywall you see the fins on the fan motor turning.

Rob,

You've provided information which answers two important questions:
- No exhaust fan discharge openings to the exterior. (not through the roof or through the soffit, I presume)
- Two exhaust fans on one switch. (you could see the blades turning in each exhaust fan)

I would write it up as:
- not having any verifiable bathroom exhaust discharges to the exterior (which is required)
- then address the issue of both exhaust fans coming on with one switch with no separate exhausts to the exterior (you did not find any, much less two) and that the two separate exhaust fans should be individually switched and have separate exhaust ducts to the exterior.

Originally Posted by Jerry Peck

I would write it up as:
- not having any verifiable bathroom exhaust discharges to the exterior (which is required)

I would say
Unable to locate ( or verify) XXX

Maybe I just didn't see or recognize it, but it may be there.
It happened!!!!
Kinda embarrassing

Originally Posted by Jerry Peck

Rob,

You've provided information which answers two important questions:
- No exhaust fan discharge openings to the exterior. (not through the roof or through the soffit, I presume)
- Two exhaust fans on one switch. (you could see the blades turning in each exhaust fan)

I would write it up as:
- not having any verifiable bathroom exhaust discharges to the exterior (which is required)
- then address the issue of both exhaust fans coming on with one switch with no separate exhausts to the exterior (you did not find any, much less two) and that the two separate exhaust fans should be individually switched and have separate exhaust ducts to the exterior.

Thanks Jerry,

I put together most of my report last night and that is pretty much what I said. I also recommend they install an attic access on the south section of the house to be able to readily access the section over the bathrooms.

I do appreciate everyone's input and different perspectives on the variety of topics listed in this forum.

Originally Posted by Jerry Peck

- not having any verifiable bathroom exhaust discharges to the exterior (which is required)

Originally Posted by Rick Cantrell

I would say
Unable to locate ( or verify) XXX

Maybe I just didn't see or recognize it, but it may be there.
It happened!!!!
Kinda embarrassing

You say 'ta-ma-to' and I say 'to-ma-to' ... you say 'pa-ta-to' and I say 'po-ta-to' ...

You say "unable to locate" ... and I say "not having any verifiable" ...

(you couldn't verify its location and I couldn't locate it either )