HELP!!!!Chimney Severe Roofing Condensation

mockas_owner

Hi,

So, had a new roof installed after we noticed all wood was rotten around the chimney. New Roofing, New flashing all good but during a repair wetness was detected between the chimney and roof in the attic. The roofing Co. Came back assured the flashing was all good.....removed shingles around but no wetness was found above....only some moisture between the galvanized metals that fold between the shingles and the chimney brick.

3 sides get very wet, where water runs down the brick and some condensationforms under the plywood why not the 4th side? This even if there is no snow on the roof ....or rain. It's winter and the average in this area has been 35 Fahrenheit.

WHATS CAUSING THIS? I belive the chimney does have a orange clay liner! Is it too big maybe? It is condensation or its definitely the flashing ? Again, no water or snow on the roof and still happens.

Jamie Hall

How's the ventilation in the attic? Is it well sealed from the living areas, and does it have vents -- eave and gable or something like that? Probably is condensation from warm moist air getting into the attic space.

nde

If flashing it sound usually the mortar, brick, stucco, etc or cap itself is cracked allowing water in. If there is not cap it could be the tile is leaking around three sides. Have a reputable chimney sweep or chimney mason check the condition. May need mortar redone, cap redone, cap installed etc. If this is a gas exhaust chimney it should be lined with stainless liner. Could be moisture just dumping into the chimney near top.

mockas_owner

Jamie,  the chimney was literally isolated. Meaning, it was insulated all  around to see if that would help. ...but it seems it got worse. More insulation was added to the around the chimney above the ceiling to better seal it from the living areas.....the attic ventilation I assume is poor at it was finished.....but all this particular area is uncovered and there is ventilation....yet the problem is there.

pecmsg

mockas_owner said:

Jamie,  the chimney was literally isolated. Meaning, it was insulated all  around to see if that would help. ...but it seems it got worse. More insulation was added to the around the chimney above the ceiling to better seal it from the living areas.....

How was this done?

mockas_owner

Nde,

Yes indeed, the mortar all around the chimney above the roof has small cracks. As a way to determine whether this was the problem, the top cover cap was removed and a temporary cap covering all crown on top was added. Then the top cap was reinstalled.....no blockages of any kind. Could it possibly be that the hair thin cracks are allowing this? Just the cold causing the condensation? Because it's definitely no water coming down from the top, again....it was blocked.

Steamhead

What kind of heating unit is connected to that chimney? Has it been serviced recently? What was the stack temperature?

mockas_owner

Pecsmg, 

We had rolled insulation cut and placed all around the chimney in the attic as a way to "isolate it" to see if the insulation would prevent early potential condensation right at that area.....but it seems to have gotten worse!

mockas_owner

Steamhead,

I'm sorry, I'm not a technician so I can't really tell you about the stack temperature but it's a Heil furnace about 5 years old......as it's fairly new, only air filters are changed

pecmsg

mockas_owner said:

Pecsmg, 

We had rolled insulation cut and placed all around the chimney in the attic as a way to "isolate it" to see if the insulation would prevent early potential condensation right at that area.....but it seems to have gotten worse!

Was this insulation installed with a vapor barrier?

Where is the chimney condensing, outside inside or both?

JUGHNE

Pictures of the furnace might explain things.
Back up to show everything, including of course the venting connections.

Include the water heater and it's venting connection.

mockas_owner

Pecsmg, I have been trying to upload pics but it won't let me.

It was installed with the vapor barrier . And this condensation forms right where the roofing plywood meets the chimney brick. Water runs down the brick and condensation forms below the roofing plywood. 3 sides

Again, roofer removed all shingles and I myself saw not water stains above the plywood. Only a bit of moisture  in between the metal placed between the shingles and chimney to divert water down.

pecmsg

So its condensing in the attic?

KC_Jones

The chimney is leaking flue gases. They are hitting the cold roof, outer chimney, or whatever cold surface is in the attic, condensing into water and running down the chimney.

It got worse with the insulation because the insulation kept all the flue gas contained to condense more efficiently.

Best guess based on what is presented so far.

mockas_owner

KC Jones,

That sounds like a very plausible explanation. Based on the fact that this issue was long present to the point that all wood had to be replaced when the roof was installed.
And yes, the insulation made things worse....

Pecsmg,
Yes the condensation is in the attic

JUGHNE,

I will try and get pictures for the furnace and all connections.

I have been trying to post pictures but I have not been able so far

pecmsg

KC_Jones said:

The chimney is leaking flue gases. They are hitting the cold roof, outer chimney, or whatever cold surface is in the attic, condensing into water and running down the chimney.

It got worse with the insulation because the insulation kept all the flue gas contained to condense more efficiently.

Best guess based on what is presented so far.

mockas_owner said:

KC Jones,

That sounds like a very plausible explanation. Based on the fact that this issue was long present to the point that all wood had to be replaced when the roof was installed.
And yes, the insulation made things worse....

Pecsmg,
Yes the condensation is in the attic

JUGHNE,

I will try and get pictures for the furnace and all connections.

I have been trying to post pictures but I have not been able so far

You stated a vaporer barrier was installed. If installed properly then the chimney wouldn't leak exhaust gasses.

ChrisJ

pecmsg said:

KC_Jones said:

The chimney is leaking flue gases. They are hitting the cold roof, outer chimney, or whatever cold surface is in the attic, condensing into water and running down the chimney.

It got worse with the insulation because the insulation kept all the flue gas contained to condense more efficiently.

Best guess based on what is presented so far.

mockas_owner said:

KC Jones,

That sounds like a very plausible explanation. Based on the fact that this issue was long present to the point that all wood had to be replaced when the roof was installed.
And yes, the insulation made things worse....

Pecsmg,
Yes the condensation is in the attic

JUGHNE,

I will try and get pictures for the furnace and all connections.

I have been trying to post pictures but I have not been able so far

You stated a vaporer barrier was installed. If installed properly then the chimney wouldn't leak exhaust gasses.

How is a vapor barrier related to a flue and whether or not it leaks?

mockas_owner

It was just insulation with its own vapor barrier that was placed around the chimney....this is why I find KC Jones view very interesting....because after this insulation, the condensation got much, much worse!

We will have that insulation removed for sure and look at the main flue to see if at that particular height the mortar failed and its causing hot gases leaks that subsequently forming that condensation

pecmsg

ChrisJ said:

The chimney is leaking flue gases. They are hitting the cold roof, outer chimney, or whatever cold surface is in the attic, condensing into water and running down the chimney. It got worse with the insulation because the insulation kept all the flue gas contained to condense more efficiently. Best guess based on what is presented so far.

KC Jones,

That sounds like a very plausible explanation. Based on the fact that this issue was long present to the point that all wood had to be replaced when the roof was installed.
And yes, the insulation made things worse....

Pecsmg,
Yes the condensation is in the attic

JUGHNE,

I will try and get pictures for the furnace and all connections.

I have been trying to post pictures but I have not been able so far

You stated a vaporer barrier was installed. If installed properly then the chimney wouldn't leak exhaust gasses.

How is a vapor barrier related to a flue and whether or not it leaks?

A chimney leaking is highly unlikely also. 

ChrisJ

I vote fart fan vented into attic.

PC7060

I’d look for a source of moisture in the building envelope. Looks for unvented or improperly vented bathrooms. Insulating the chimney may have reduced the area where the moisture could condensate so more moisture ended up on the cold underside of the roof. 

JUGHNE

I ask about pictures because, it has happened that a condensing furnace was piped directly into a masonry chimney.

"New furnace 5 years ago"

PVC coming off the furnace stuck into the chimney would be an obvious.
Happens more than one would think.

PC7060

JUGHNE said:

I ask about pictures because, it has happened that a condensing furnace was piped directly into a masonry chimney. "New furnace 5 years ago" PVC coming off the furnace stuck into the chimney would be an obvious. Happens more than one would think.

Agree @JUGHNE, improperly vented bathrooms as well. Similar to what Dan was recently quoted regarding troubleshooting steam systems, the solution is rarely in the same location as the problem.  

ChrisJ

The new insulation made it worse because the attic is colder now.

mockas_owner

Furnace and water heater

mockas_owner

Actual brick flue base was wet as you can see in the picture and the residue inside as well 

ChrisJ

Is that romex right up against the water heater flue pipe?

And a fabric tarp draped over the water heater and drafthood?!

mockas_owner

Flue interior  picture taken in the basement and the problem manifest 

mockas_owner

No its just coaxial cable garbage 

PC7060

That chimney looks terrible. You should really consider installing a liner to service the heat and hot water. 

I assume that’s the before picture the chinmey
clean base clean out?

Jamie Hall

Hmm... you may have a condensation problem inside the flue which is somehow getting out -- which means the chimney, lined or not, has cracks or bad joints. And it is oversize for the appliances going into it. I'd agree -- a liner, material and size appropriate to the appliances, is needed anyway, even if condensation isn't the problem.

And I also agree. What is that tarp doing over the water heater? The draught hood is intended to be free drawing.

JUGHNE

I would say the WH cover/blanket is a health and fire hazard.

One case like this, the brick was taken down to the attic floor, then "B" vent was lowered down to the new chimney opening in the basement.
Came out of the chimney with double wall "B" 90's.
Roof closed up and B vent up and out the roof.

You could do a flex liner but someday the masonry above the roof will fail and you start over.
The B vent solves that problem permanently.

You could relocate the WH to the front of the chimney to shorten up that run and the run of the furnace.

mockas_owner

What size of the flexible liner should I use for this? Or should I use Galvanized? And what size?

Please advise,

People are working there...the tar will be removed and the flue was cleaned at the base

Bob Harper

You really need a chimney pro in there that knows what they're doing. So much going on. First of all, you cannot pack insulation or anything around a chimney. You must maintain a 2" clearance to combustibles air space around the chimney. It must be properly firestopped. The chimney must be properly lined, which it is not. The vent connectors must be replaced and properly supported. There is insufficient vent rise off the furnace. The exterior masonry is a separate issue. Regardless if a chimney is used, you must keep the water out of the building. That starts with a rain cap, spark arrestor/ animal guard, overhanging cast concrete crown, dampproof course with weep holes, masonry preferrably laid in lime mortar then treated with water repellent that is 100% vapor permeable, proper step and counterflashing that is 'let' into mortar joints- not caulked or nailed. If the chimney is greater than 30" wide, it needs a cricket uphill to divert water around it. Due to the inadequate clearances alone, it must be lined. This must be sized properly. I would bring the WH and furnace together into a manifold with one breaching as high as clearances allow. You can install a condensate tee in the base of the ss liner. No galvy pipe cemented into the wall. A listed liner does not require a cleanout.
As for flue gas condensation, you must run combustion analysis to know what's going on. You can also measure the exhaust temps. at the top of the chimney with the appliances individually then together and observe condensation. If condensation continues to be a problem, you can install double acting barometric dampers with spill switches and that will reduce it. Also, ensure that furnace has a post-purge of about 4 minutes.
HTH

Ciupaga_PL1

mockas_owner said:

Flue interior  picture taken in the basement and the problem manifest 

Where is the insulation in the 1st picture? Look's like you have non on the ceiling. That's what's causing the problem. 
Also do you have baffle vents in the attic? and soffit vents? Roof vents? 
You need more inflow air in the attic then outflow 

This is definitely not a chimney issue. If you had to change all the wood you're getting heat loss in the ceiling and possibly near the edge around walls. 

Ciupaga_PL1

Can you take a picture of chimney flashings and roof. 
If it's a reputable roofer or a cheap roofer? Was it subbed out to another company? 
Sub roofers usually don't care because they get paid per square and don't want to waste their time. 
I've been roofing 20 years, most common condensation issues.
No insulation near the edge of the house, its hard to push it in there with the roof deck in the way. If it's blown insulation then the air coming in through soffits will eventually blow it back. 
No soffit vents/intake vents, no baffle vents.
Bathroom exhaust pipes not connected or not insulated 

mockas_owner

Ciupaga, PL1,

See roofing pictures attached and the flashing.
Again, roofing shingles were removed and no wetness or water stains detected, unlike underneath......so its clearly condensation.

There is plenty of air flow around 3 sides of the chimney, 4th is poor....there are vents in the soffit 

mockas_owner

Update, the insulation around chimney in attic was removed since as stated, it had worsened the condensation.
And that insulation was placed in the attic area floor close to the chimney to prevent heat escape...more was added.
You could tell that this alone reverted the condensation to the original level.
After cleaning the base of the chimney flue, we started to notice wetness at the base as well....

We checked the furnace and it's a 80k btu, for a poorly insulated 970 sq ft home with a finished attic but no heating vents to it.

Could it possibly be that the unit is oversized and causing excessive moisture issues? By cycling warm air?

We have ordered a  6" chimney liner to install it and channel this potential moisture outside more efficiently......your thoughts gentlemen?
Will this help?

ChrisJ

Is the chimney leaking when it rains?
Is the top of it sealed correctly? Is a proper rain cap installed?

pecmsg

You need a Cricket on the uphill side!

mockas_owner

ChrisJ, no, the days when there was no snow or rain the condensation still accumulated.