Chimney/vent Brick Crumbling

Does this look like it needs to be rebuilt from the roof-level up? House is about 100 years old. Was flipped 5 years ago, looks like the flippers just painted over it without actually repairing the brick chimney. As you can see in the picture, a few chunks of brick have fallen out.

I’m having my modified bitumen roof coated with a fibered sealant, and the roofer also gave an estimate to re-build the chimney for about 2k. Do you think it’s worth doing, or not necessary?

Not sure if this matters, but we don’t have a fireplace or anything I’m the house. Could this be a false chimney? A bit out of my element on what the purpose could be. If it doesn’t serve a purpose, can we just get rid of it?


Thats pretty rough. How will he rebuild it? A complete demo and new brick, including caps and flashings? Do you have something that runs on public service gas? A water heater maybe?

I dont think hes “re-building” it.
Maybe he is.
I just think hes charging you 2k extra to waterproof it and warranty it.
Which i still feel is reasonable.
I wouldnt charge you much just to coat something.
You get charged handsomely when i permanently solve a leak issue and warranty it.

1 Like

Looks like flexible b-vent sticking out the top. It’s common to vent gas furnaces/water heaters out through the chimney.

You can check in the basement to how they are set up. If they’ve been upgraded to high-efficency models (different vent method) or electric (no venting) and the chimney truly isn’t in use them you do have the option of removing it. If you have no fireplaces in the house, the chimney’s original use was probably a coal burning furnace.

Check to make sure the furnace/water heater are connected to the liner. The higher efficiency blower assist furnaces produce mainly steam and CO. When it’s blown from a 5" pipe into a 12’X12’ masonry chimney it condenses due to lost velocity and the cold brick. Saturated mud brick spalls like yours. I do alot of liners after the chimney has been rebuilt, reflashed, and caulked with 20 kinds of “AwesomeCrap!” in a tube. I’ve also seen liners dropped and not connected properly that will still spall the brick.

Thanks all for your responses so far. A few questions and answers:

  • My understanding after talking with the company was that they are going to rebuild with new brick and then properly flash it. The formal estimate I received also says that they will “rebuild the existing chimney from the roofline up.” I did my homework, and they’re a reputable company.

  • We have an electric water heater manufactured in May 2015. Our HVAC is on our roof. Note that the electric water heater itself is on the other side of the house from where that chimney is.

  • Note that there is a jutting-out from the wall that runs up the side of that part of the house - rectangular in shape - and I’m pretty sure that it runs directly up into the chimney on the roof. I’m also pretty sure there are metal beams framing the aforementioned rectangle jutting out. Apologies for my lack of proper terminology here. Anyway, I had thought that may have been where a fireplace was that led up to the chimney, although the only reason I have to think that is chimney at the top. It may have been changed into a completely structural component when it was flipped. Don’t really know! Is that helpful at all in determining whether or not it is necessary? Don’t want to make any rash decisions here, but I imagine demo + flashing over it may be cheaper than demo + rebuild + flashing.


If nothing is running through it, take it down to the parapet, fill the top couple feet with insulation, and cap it off. Below the parapet is structural.


Sounds like its best to remove it.
Shouldnt cost too much.
500-1000 sounds fair.

Thanks, all. If I could just get rid of it, it sounds like that would save me a lot of money!

Is there any way to confirm that nothing is running through it?

Would a roofer be able to tell that, or would I need to have someone else come and take a look? If so, what type of professional could I ask to do that? I’d obviously want to confirm that there’s no risk to removing it.

Start in the basement and go floor to floor looking for anything penetrating the chimney. Remove and patch any dead flue pipe. Put a battery operated CO detector on the cap to check for flue gasses.

1 Like

Holy fucc dark you’re so experienced, I think those guys pushing papers in stem labs should create some gadget to pull out all information from memory and spare it with anyone :smiley: I want your 60 year roofing experience right now

Not sure is that’s sarcasm, but my list of experts in various fields is dwindling. Few of them had formal education past high school. The passing of an old tradesman is the same as the destruction of a library.


Nope,I’m dumb and need more experience

Lucky you don’t have to re-deck and cut a few valley jack rafters!

1 Like

Hey everyone - Thanks for all of your responses. I had two chimney guys come and take a look at it and everyone was in agreement that the chimney doesn’t serve any function anymore.

Seeing as the brick in the chimney is spalling and the chimney no longer serves any purpose, we think it would make sense to just take down the chimney when we have work done on our roof in the next few weeks. After the chimney is demolished, it looks like we’ll have two options: (1) seal it and put a new crown on it, or (2) seal it and then roof over it.

Is one of those options better than the other from a roof-maintenance and leak-prevention perspective? And, if so, which one of those options would be more expensive? Just got an estimate today to seal it and put a crown on it for $1350.

Interested in hearing your input on this! Thanks in advance.

I would repurpose it(if possible). I would then use the opening as a vent for the kitchen or bathroom, or tie in all of the bathroom venting into on large one.

Any vents in the roof is a major source of leak. Chimneys are a notorious source of leaks.

What are you proficient at?


Nothing related to roofing.

That was directed at Teesla…

Oh, got it. Well any input would be appreciated!