Return register on ceiling in garage above gas water heater

**mark petty** · 02-03-2017, 05:21 AM

The Villages, FL
2002 home with natural gas water heater in attached garage.
Return register above unit that just vents into attic; does not connect to HVAC system
All homes in this area have exact same situation.
Can anyone tell the purpose of the vent opening?
Does it have something to do with expelling a gas leak?
Thanks, Mark

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**Dom D'Agostino** · 02-03-2017, 05:44 AM

It's for combustion air.

Dom.

**mark petty** · 02-03-2017, 06:34 AM

You'd think the garage itself would supply enough combustion air. As I understand; the garage should be air tight from the home, attic, crawlspace etc to prevent auto exhausts from migrating to the interior. Kind of conflicting. Would like to hear more on this.
Thanks

**Jerry Peck** · 02-03-2017, 07:39 AM

As Dom said, it's for combustion make up air.

I would think that a garage would be large enough to not require additional combustion make up air, but nothing prohibits adding more ...

... except for one thing.

If that is just an opening and does not go from the garage, through the attic, to the outdoors ... then that is a hole through the separation between a garage and the living space and it's attic.

It is also possible, but highly unlikely, that the wall between the garage and the living space is continuous to, and sealed to, the underside of the roof sheathing, in which case simply a hole through the ceiling would be okay.

**mark petty** · 02-03-2017, 08:05 AM

Jerry, Dom thanks
I agree on the breach in the fire rating of the ceiling and no, there is no firewall separating the garage attic from the living area attic. The register on the garage ceiling just has a short section of pipe (12" tall and 12" diameter) going up into the attic and not through the roof. As noted; all homes around this one and other locals in the Villages have this same situation. I guess I'll just explain the situation and have buyer discuss it further with the building department unless someone has a better idea.
Thanks again.

**Jerry Peck** · 02-03-2017, 08:49 AM

I had a long post almost completed on my phone and the browser closed and reopened ... losing the pot. Urrrgh!

I will have to retype it later from my computer. Urrgh!

**mark petty** · 02-03-2017, 09:24 AM

okay, thanks Jerry

**Gunnar Alquist** · 02-03-2017, 10:26 AM

Originally Posted by Jerry Peck

I had a long post almost completed on my phone and the browser closed and reopened ... losing the pot.

Technology is soooo wonderful!

**Jerry Peck** · 02-03-2017, 01:49 PM

Originally Posted by Gunnar Alquist

Technology is soooo wonderful!

Yessss it isssss (at times).

The result, though, is that it allowed me to make a drawing instead of just explaining making the drawing.

Not sure that was worth losing that entire long post, though.

Originally Posted by mark petty

I agree on the breach in the fire rating ... firewall separating
.
I guess I'll just explain the situation and have buyer discuss it further with the building department unless someone has a better idea.

First, addressing some incorrect terminology:
- "fire rating": there is not "fire rating" for anything to breach
- "firewall": there is no "firewall" (or "fire-resistance rated horizontal assembly" is what a rated ceiling is), a "firewall" is a specific thing, a "wall" for one thing, and there are no "firewalls" in dwelling units

Second, YOU need to be the one to ASK the building official about it in such a way that you are clarifying your understanding of the requirements - and using the proper terms so you are not dismissed as 'not knowing what you are talking about'.

Then, your method of that clarification needs to clearly explain what he may not be aware of that is going on (which gives the building official to agree with your understanding - making you look better in his/her eyes), and gives the building official the opportunity to get with his inspectors and the contractors, and ... hopefully ... not ignore what he is now aware of.

Take a drawing with you which shows the scenario, I have attached an example of a drawing you could use showing the actual scenario which exists.

When you are ASKING the building official to help clarify your understanding of the code, you can use your drawing and walk through it, something like:

Mr. Building Official, I would like to make sure that I have a proper understanding of the requirements for separation between a living space and its attic and a garage (pointing to the drawing to the various items as YOU question YOUR understanding of the requirements) - this is the living space and its attic, and this is the garage, my understanding is that separation is required between the garage and the living space and its attic, such as like having a separation wall here and a ceiling which serves as the separation from the attic here, am I understanding that correctly? (don't have that opening shown on your drawing, you will draw that in by hand soon enough)

When the building official says something like 'That is correct, this wall needs at least 1/2" drywall (he may call it "gypsum board", which is the correct term anyway) on the garage side, and the ceiling needs to be at least 1/2" drywall too, just like you show.'

You then continue to set the hook with something like 'Good, I wasn't sure if I understood it right or not.' ... brief pause ... "Here is why I was wondering if I was confused, I frequently find what looks to be a combustion make up air opening through the ceiling above the water heater (draw the opening and short piece of duct on the drawing), the bottom is a return air grilled, the duct is 12" diameter and about 12" tall, it is open to the attic ... that makes a 12" hole through the separation ceiling, doesn't it?' ... don't pause too long, you want to continue before he has time to respond ... 'Shouldn't that duct go all the way through the attic to the outdoors so it is not an opening into the attic?'

You now wait for him to think and respond ... and there really are only two responses: a) that combustion make up air opening should not even be there; b) yes, if combustion make up air is needed, then that duct needs to go through to the outdoors. Then, hopefully, the building official adds 'You say you find this in a lot of homes? Where?' That is when you clarify that they are in his/her AHJ.

Will likely take it hook, line, and sinker.

**mark petty** · 02-03-2017, 02:06 PM

Jerry,

Can't believe you took the time to put all this together. You nailed it very well. Can't thank you enough. I won't be going to the building department but will relay this info and drawing to customer so he can better explain himself and have the fun.

Mark

**Garry Sorrells** · 02-04-2017, 08:56 AM

Originally Posted by mark petty

Jerry, Dom thanks
.........As noted; all homes around this one and other locals in the Villages have this same situation. I guess I'll just explain the situation and have buyer discuss it further with the building department unless someone has a better idea.
Thanks again.

Originally Posted by mark petty

Jerry,

Can't believe you took the time to put all this together. You nailed it very well. Can't thank you enough. I won't be going to the building department but will relay this info and drawing to customer so he can better explain himself and have the fun.

Mark

Mark,
Exactly why would you not go to the building department and get the answer straight from the horse's mouth. Then after you knew the reasoning for your self you could report back and share that info with the rest of us. Especially Jerry Peck who went to alot of effort to assist you with your questions.

**Jerry Peck** · 02-04-2017, 12:38 PM

Originally Posted by Garry Sorrells

Mark,
Exactly why would you not go to the building department and get the answer straight from the horse's mouth. Then after you knew the reasoning for your self you could report back and share that info with the rest of us. Especially Jerry Peck who went to alot of effort to assist you with your questions.

I'm not concerned with any time making a drawing as we all can learn from it and/or the drawing gets corrected to represent what is there that I guess wrong on ... my concern would be 'does the building official know what is being done' (apparently his inspectors know, or maybe they think the duct goes all the way through to and through the roof), i.e., does the building official actually condone and approve that practice - which leads to what Garry said " ... go to the building department and get the answer straight from the horse's mouth. Then after you knew the reasoning ... " that reasoning would be very interesting to know (provided that the building official actually approves that practice).

Mark,

Do you know if the AHJ for The Villages is the Sumter County Building Department? If so, is the Building Official Steve Wilcox?

Will you find out and verify - I will send a letter stating that this practice is being done in his jurisdiction and that I am just letting him know it is being done.