Direct Vent Flue Clearance

[Michael Chambers]

Is there some guidance or standard/code on vertical clearance for direct vent fireplace flues? This one measures 3 ft. 11 in from the top of the direct vent flue to the vinyl siding components under the framed chase above. And before anyone mentions it, the obvious thing would have been to get the make model number of the unit, but it's not helping me to think of that here at home a couple of hours later. That's why I'm asking the brain trust here. This is a 19 year old home, with no heat damage to the vinyl siding components. I do imagine however, that this fireplace was added at some time after the house was completed. As always, thanks for your help with this.

Mike Chambers
St. Louis, Mo.

[Bob Harper]

Well, without the obvious, you don't know.

That termination was done improperly and will leak water. Makes you wonder what else is wrong. As usual, get a pro in there.

Make, model, serial number
Make, model, serial number
Make, model, serial number.....

[Fred Weck]

Typically it's 30" to vinyl soffit, 18" for other materials.

[Ken Bates]

I agree with Fred Weck.

On Thurs. 3/10/11 I attended a seminar that covered just about every issue re these direct vent units.

30 inches is plenty of room.

Hard to find any code directives on these so it is the manufacturers advice that is followed.

If it were 18 inches below the bump out then there might be a small diverting shield on top of the outer plenum (forgot the term for the termination cage)

It can be even closer (12") with other siding.

Looks good to me.

See if the bump out area is cold inside the unit.

Builders sometimes omit the insulation that is to be put at the base of the bump out.

How is the glass in the frpl.?

Is it clear or does it have a filmy haze.

A haze that remains is sulfur compounds and will permanently etch itself into the glass if left for a few months.

[Michael Chambers]

Thanks all for the help with the clearance question, and that was a good tip on a hazy film on the glass. I wasn't aware of the potential there, and have seen that before in other houses, but not in this one.

Bob, what exactly is your observation on the termination? I was thinking that the vinyl siding wasn't cut back enough, and should have been finished with flashing and a J-bead, and I didn't like the angle at the top caulked to the siding. That again should have been cut back more, and should have had a rain cap flashing slid up under the siding to bring water to the outside.

[Bob Harper]

The siding should have been cut back, the framing cut-out tape flashed, termination screwed to wall, caulked top & sides, J channel, then siding tucked in. There is a rain gutter built in to the top of that termination.

Haze on glass is primarily from silicone off-gassing, not just acids. There is only a trace of sulfur in gas these days but you do make carbonic acid along with a dozen others. They make special cleaners for gas fireplace glass but you can use Brasso or Noxon metal polish, too. Just use a soft cloth in circles as though you were compounding a car's finish because that's what you are doing--grinding the crud off with a microabrasive. Then use a non-ammoniated glass cleaner because ammonia has been linked to causing a rainbow discoloration of glass that gets heated.

I know of some units from this mfr. that require a 42" clearance to a soffit so as I continue to state on this forum, refer to the listed instructions because you can never ASSume.

[Michael Chambers]

Thanks Bob! Good info for all of us! I've seen the rainbow discolored glass before, and just thought that was the result of the manufacturing process. I kind of like the affect, and now I know how to get it.

[Corn Walker]

They make special cleaners for gas fireplace glass but you can use Brasso or Noxon metal polish, too. Just use a soft cloth in circles as though you were compounding a car's finish because that's what you are doing--grinding the crud off with a microabrasive. Then use a non-ammoniated glass cleaner because ammonia has been linked to causing a rainbow discoloration of glass that gets heated.

I'm pretty sure both Brasso and Noxon 7 contain ammonia (in the form of ammonium hydroxide). Rutland's #84 conditioning glass cleaner isn't as effective (in my opinion) but according to their MSDS doesn't contain ammonia.

[Bart Ogden]

I'm pretty sure both Brasso and Noxon 7 contain ammonia (in the form of ammonium hydroxide). Rutland's #84 conditioning glass cleaner isn't as effective (in my opinion) but according to their MSDS doesn't contain ammonia.

We have had excellent results from using Rutland's #565 White Off and following up with Sprayway ammonia-free glass cleaner.

Brasso definitely contains ammonia (5 - 10%) and is pretty nasty to work with as indicated by the MSDS sheet. DANGER: HARMFUL OR FATAL IF SWALLOWED. EYE AND SKIN IRRITANT. VAPORS HARMFUL IF INHALED. COMBUSTIBLE. Do not ingest. DO NOT inhale. DO NOT breathe dust from dried product. Use product in a well ventilated area. Keep away from heat, sparks and flame. Keep container closed when not in use. Contains petroleum distillates and silica.

We've found that the non-combustibility of the White Off and the Sprayway are a much safer combination to work with. You also don't have to worry about the VOC's coming off the brasso when you use the White Off and Sprayway.

Bart Ogden
Wichita, KS