Installed Chiney Cap -- now smoke lingers, any advice?

[DrRod]

Last year I discovered that our stone chimney was losing some of its mortar. I had a mason come and fix it. He also made a concrete lip around the top and installed a cap. The place is 75 years old and we never had a cap before. Also should mention that the chimney has two flues in it: one from the fireplace and a smaller one from the basement that used to service a big wood furnace until the 50's. We also put a cap on it.

The cabin sits in a slight hollow that funnels air down from the mountain. This makes for a welcome cool breeze in the summer. The prevailing winds and weather come from the west but the mountain right behind us is east so there is this natural churn of air -- sort of bouncing off the mountain and rolling down the hollow.

So the problem is that the smoke now churns around the cabin. It used to go up in a high plume and blow away but now it circulates around the house. You can go out on the porch and see clouds of it. The cabin [chestnut logs from the 30's] has plenty of leaks so some of it gets pulled inside. And when the weather is right you can find a layer of smoke in the basement.

The basement is rock walled and dirt floored and moisture is always a problem. I considered closing off the second flue as it may be sucking smoke into the house but it may also be more useful as a conduit for air flow helping to dry out the basement. And in any case I don't think that is the main source of the problem.

So is the cap worth it? Anyone ever rigged a pop-up cap so it can be opened when burning? Any other thoughts?

Thanks

 

[CalG]

Last year I discovered that our stone chimney was losing some of its mortar. I had a mason come and fix it. He also made a concrete lip around the top and installed a cap. The place is 75 years old and we never had a cap before. Also should mention that the chimney has two flues in it: one from the fireplace and a smaller one from the basement that used to service a big wood furnace until the 50's. We also put a cap on it.

The cabin sits in a slight hollow that funnels air down from the mountain. This makes for a welcome cool breeze in the summer. The prevailing winds and weather come from the west but the mountain right behind us is east so there is this natural churn of air -- sort of bouncing off the mountain and rolling down the hollow.

So the problem is that the smoke now churns around the cabin. It used to go up in a high plume and blow away but now it circulates around the house. You can go out on the porch and see clouds of it. The cabin [chestnut logs from the 30's] has plenty of leaks so some of it gets pulled inside. And when the weather is right you can find a layer of smoke in the basement.

The basement is rock walled and dirt floored and moisture is always a problem. I considered closing off the second flue as it may be sucking smoke into the house but it may also be more useful as a conduit for air flow helping to dry out the basement. And in any case I don't think that is the main source of the problem.

So is the cap worth it? Anyone ever rigged a pop-up cap so it can be opened when burning? Any other thoughts?

Thanks

In this area, caps serve as a condensation plate for the H2O part of the combustion equation. What a mess!
Caps come off mid winter of the first year, not to be replaced, for anyone burning wood.

But it is cold here at times. ;-)

 

[zzvyb6]

It's likely that fixing the mortar stopped warm feed air from entering the chimney. So, with less heat in the flue(s) smoke and exhaust cool sooner. Try opening the other flue to get more air in there and see if the smoke rises higher.
I doubt it was just the cap change that has caused this new problem unless it is blocking the rise of warm air from below it.

 

[BoylermanCT]

If you are using a wood stove or insert, I would buy a chimney liner and insulate it. The liner will make a smaller chimney flue, and that will increase your draft. The insulation will keep the smoke hotter and it will also draft more. Higher draft will cause the smoke to go up and out of the chimney. Made a big difference in my brick chimney.

 

[pyro29]

Another option...stop with the wood non-sense and start burning anthracite coal.

After 25+ years, we switched from wood to coal and it was the best thing we ever did. I routinely get 35+ hour burn times without tending, the house is much warmer (sometimes too **** hot), and, to address your concerns, there is neither smoke nor creosote. Pulling up the driveway, you'd actually never know that there is anything burning at all. Hard (anthracite) coal, unlike the soft bituminous coal, doesn't produce that nasty black smoke nor does it pollute the air.

Our chimney has a slate cap (not removable) and the house is on the side of a large hill / small mountain which gives us some crazy wind patterns. The back yard would routinely fill with stagnant smoke when we burned wood. No longer have any issues.

Coal is available both in bulk and in bags on pallets.

 

[Ford850]

That second flue could be adding to your problem. If it isn't being used, I would cap the top to seal it. That might be what you meant was done already, but if you meant you added a screened cap, I would seal it tight instead. Sometimes that second unused flue stays cool and acts as an inlet for replacement air to the house. With the new cap on the wood stove flue, the smoke is easily pulled back into the smaller flue and into the basement.

 

[DrRod]

That second flue could be adding to your problem. If it isn't being used, I would cap the top to seal it. That might be what you meant was done already, but if you meant you added a screened cap, I would seal it tight instead. Sometimes that second unused flue stays cool and acts as an inlet for replacement air to the house. With the new cap on the wood stove flue, the smoke is easily pulled back into the smaller flue and into the basement.

That's sort of what I've been thinking. The second flue I open from basement to chimney top with just a screen and cap on top. I thought of blocking it from the bottom with some sort of door so that it could be opened in summer -- the air flow through the basement is important given the inherent dampness.

But we never had the smoke problem until we put the caps on. The fireplace is big and draws well so I have to think the problem is at the top. I'm no longer sure of the cost benefit of the cap if it keeps the smoke so close to the house.

 

[Egon]

That's sort of what I've been thinking. The second flue I open from basement to chimney top with just a screen and cap on top. I thought of blocking it from the bottom with some sort of door so that it could be opened in summer -- the air flow through the basement is important given the inherent dampness.

But we never had the smoke problem until we put the caps on. The fireplace is big and draws well so I have to think the problem is at the top. I'm no longer sure of the cost benefit of the cap if it keeps the smoke so close to the house.

Consider installing a dedicated inlet for outside air for the fireplace.

If the cap offers any constrictions these may create a turbulence that reduces draft and changes flue gas velocity. Outlet to small for the inlet?

Best solution would be an airtight insert or free standing stove with the proper flue diameter insert. It may seem costly but it will give more heat for less wood burned with increased interior comfort.