> Help on Home Water Leak and Gas Vent

[hammersley]

OK - I have a Bumpout that only serves as place for my Fireplace - that is a gas zero clearance. If you look at these photos you'll see what I mean. Now I have a shop under my house - only because it was built on a hill and I have access to the area underneath - it wasn't planned as a walkout basement. Now where the bottom of the bumpout rests on the sill plate there is some water seepeage about 1 foot up from that sillplate. (I can only see that from the inside because that area is not finished - so I can see the OSB and the 2x6's - the outside siding is Hardiplank) I notice water at the spot where the CDX was joined down to the sill plate - which is a seam where the bottom foot was added during frameup. I also noticed that some of the nails - for the CDX that missed the 2x6's - have a drop of water on them... . NOW here's the issue..... THERE IS NO WATER INSIDE above that bottom section..... i. e. it is not running down from the inside..... I think it's coming between the OSB and the Hardiplank - BUT WHERE!!!!



Now I might also mention that this does dry up in the summer - so there's no internal water issue..... and no water pipes near here..... and no water damege anyplace else..... several of us have looked at this and we are stumped.....



Everything is sealed up tight as a drum SO I think it's either the Bump Out Roof... OR THE GAS FIREPLACE VENT... .



Look at these photos... . my question is this - How does this fireplace vent deal with rain water???? There is no cover for it and this is common on these in my neighborhood - although many are closer to roof line cover. I mean in my application you can see that it will get water dripped onto it from the small roof section above and any wind blown rain... . now this does face North - but it will get a bunch of rain from the roof section... I don;t understand where any water would go if blown in or dripped in...



Had I not had access to this area I would never have known about this issue - makes you wonder how many people have a problem like this and don't know about it.....



#ad


#ad


#ad

 

[Little Bill]

If you only see it during the winter and if you are using the gas fireplace during the winter then it may be condensate leaking from a joint in the vent. You make a lot of water burning natural gas or propane.

 

[hammersley]

How hard is it to fix that.....I mean when you look at the photos...

I guess you can take that off and see what's underneath... ...

 

[Little Bill]

I'd start by pulling the hat off the vent and sticking my arm in there to see if it's wet or if there is a puddle. Then you can investigate options like maybe insulate the vent pipe or stab in a drain at the low point. Burning it harder might be enough to increase both the vent pipe temp and the velocity to carry the water vapor all the way out.

I had a similar problem with a super high efficiency natural gas heater. Not enough temperature in the exhaust gas to avoid condensation. Corroded the 3' galvanized vent tube in 1 year. Went to s/s, insulated and added a drain in the first elbow.

 

[Hoefler]

It is most likely condensation from the incoming air from under the house the fireplace draws in for combustion. Most zero clearance fireplaces require an air source from somewhere other than the living space. It is drawing moist air from under the house. To fix this, you will need to install a duct from the fireplace to the outside and seal off the area from underneath the house.

 

[kenny61]

To fix this, you will need to install a duck from the fireplace to the outside and seal off the area from underneath the house.

Whats a duck gonna do and wont PETA get upset?



:-laf:-laf:-laf:-laf



It looks like there is no flashing where the top of the vent meets the siding make sure the caulking has not dried shrank and cracked or if it was ever caulked at all. Sounds like it is condensation if it only happens in winter when using the fire place. but check the top of the vent anyway