Garage Chimney Repairs & Planning Ahead

[mnowaczyk]

I have a detached garage with a chimney that I plan to get repaired and capped with a concrete cap like that on the house in the coming week.



I think I want to put one liner in each floor of the chimney planning ahead for whatever various thinks could possibly be done inside this garage that has a 100 amp power panel, natural gas, water and sewer and also houses the pool pump and filter stuff. I hope to build a bathroom in there and maybe create a guest house some day.

But now I need to protect the chimney and it’s stucco. Water obviously enters the chimney and shows cracks in the stucco every time we get a lot of rain. I have a great stucco and chimney guy that is willing to do the work, but I want to make sure I choose the right chimney liner materials for this all masonry chimney:

- double wall?
- Terra cotta?
- stainless?
- galvanized?
- aluminum?
- vermiculite?

While I understand as a GARAGE the space may not legally house a wood stove, I could see possibly getting around that in the future somehow, like maybe removing the garage door, or dividing interior space. You never know.

Now upstairs, the floors are wood. And heat rises so well, I don’t see ever installing a fireplace or wood stove upstairs. Maybe a heater, water heater etc could possibly go upstairs.

So maybe two different types of liners should be installed. Then fill with vermiculite. Then somehow block off the top around the liners with some non-flammable material. I’m thinking of something like plywood but obviously not plywood. Maybe concrete tile backer board would work well. Then the chimney can be capped with concrete like the house.



wood stove? Well, it would be wonderful to be able to have an open fireplace which would require a big flue. Right? I’ve only really got a max of ~8”x8” x2 that I can fit in the chimney. Maybe that’s plenty. Just do terracotta?

My chimney guy is ready to start, but I want to make sure this gets done right. I will post some video I took.

 

[mnowaczyk]

3rd of 5 videos:


4th video of 5:

 

[mnowaczyk]

So I guess I need to figure out what appliances I want to install in order to figure out what size liver(s) I should install. I’d love to get this chimney situation all ironed out, but I guess the fact is that I may be trying to plan too far ahead.

BUT… if I could always slip a smaller liner inside a larger one, that may be an argument for just installing two 8” round liners now to have something done.

Whatever I do, I’m going to need rain deflectors on the tops of the liners so I don’t just have water draining inside the liners into the living space below.

Maybe I should really be investigating caps like a spring loaded cap for an open fireplace. Hmm

 

[bholler]

So I guess I need to figure out what appliances I want to install in order to figure out what size liver(s) I should install. I’d love to get this chimney situation all ironed out, but I guess the fact is that I may be trying to plan too far ahead.

BUT… if I could always slip a smaller liner inside a larger one, that may be an argument for just installing two 8” round liners now to have something done.

Whatever I do, I’m going to need rain deflectors on the tops of the liners so I don’t just have water draining inside the liners into the living space below.

Maybe I should really be investigating caps like a spring loaded cap for an open fireplace. Hmm

There is absolutely no reason to have it lined until you know what is being installed it would be a waste of money otherwise

 

[mnowaczyk]

There is absolutely no reason to have it lined until you know what is being installed it would be a waste of money otherwise

Contractors are hard to get a hold of, and I really want to make sure this chimney doesn’t fall apart and was planning on having it capped with concrete like the house was done (off at the edge of the picture in the top post). But not knowing what liner needs to come out the top is what I’m struggling with.

If we went with two 8” terracotta, liners, which I believe would fit nicely, they’d have to be stacked all the way to the bottom of the second floor where the chimney gets narrower on both sides. If we did this, I’d still likely have to bust out some terra cotta in order to get metal liners in later.

So I’m thinking that just putting in the largest possible metal liners might make sense. Maybe just doing that with the cheap corrugated stuff would be good enough, as this chimney might never even get used. However, this video shows how going for “light heavy weight” smooth wall makes a ton of sense if you want something strong.

But again, without having a defined purpose, I understand this is premature.

Could the mason just put a single section of terracotta at the top to be able to make his concrete cap? If so, what would support the Terracotta? Terracotta seems cheap enough, and when I only really need about 30 feet total, about 16’ - 17’ to get to the first floor opening, and about 10” to get to the second floor where I could envision a second opening, it’s hard to call it a waste of money if it will make the chimney usable. Right now, it’s just a single layer of brick that can’t really be safe for any type of use. Maybe I could put a tailpipe exhaust tube into it for working on vehicles, but even that isn’t safe. LOL.

 

[mnowaczyk]

So i called up the HVAC supply house to give them a rundown of what I’m looking to do, and they said they only inventory/carry a 6” stainless corrugated liner that comes in a 35’ length which is $765. This could be an option for me, but they are out of stock, and with this week being a holiday, it sounds like it’s not coming in this week.

That gets me thinking crazy thoughts…

If I’m just looking to build a conduit to later put a smaller liner into, terracotta makes sense, but maybe just using some frigging HVAC duct will make just as much sense for what I’m trying to achieve here. Even that would be better than just a single layer of brick. I could easily stack 8” galvanized HVAC pieces screwed together from the inside out so the screw points don’t stick into the inside of the duct. That seems like it would be better than nothing. But I don’t know, especially if it’s just bound to rot away into a huge mess to need to be removed.

 

[mnowaczyk]

So I talked to Delaware Brick before they closed at noon on Saturday, and they’ve got 8x8 Terra cotta in stock, $20 each. So with less than 30 feet needed, 15 sections, that will be $300. That sounds like it will be by far the most cost-effective option to have some type of liner installed.

Figuring out how to drop the liners in, preferably side-by-side and stacked nicely may be the challenge. I feel like this is some old-world work we are about to embark on, but I’m a little excited.

Making openings to assure that appliances can be hooked up in the future will be a concern too.

The first floor work will require that the liner be cut so the bottom where the liner sits doesn’t become a problem where it necks-down on the first floor. So cutting the middle wall out a little for each of the bottom liners will be required.

The second floor requires giving out where we want to put the hole in the chimney on the inside. That requires determine required clearances to combustible surfaces. I would guess the worst case scenario would be a water heater. A wood stove on the second floor of the garage would make no sense IMO. I’ve seen some neat tiny little wood stoves in a “tent dining” restaurant a few years ago. So MAYBE a tiny little wood burner could be very cool to have. Water heaters can be electric. But maybe also run indirect off a modcon or even a tankless. I had considered planning to buy a modcon for the house and buy an identical one for the garage that I could pilfer for parts in the event of a failure in the house. So really a modcon is the ideal heating option. I could vent that through the short second story chimney. That would likely have far less issues with distance to combustibles. So… maybe wood stove / fireplace on the first floor of the garage and modcon on the second would be the most ideal setup.

To take it to the next step. Since pool equipment is in the garage, the ability to have heat exchangers from both a modcon and also a wood-burner would be awesome,

So not to figure out where to bust into the chimney on that second floor.

 

[stoveliker]

Regardless of this all, if you have wood (roof etc.) or other combustibles touching the 1 course brick of the chimney, any liner needs to be insulated.
So if you put 8x8 terracotta in there, is that the outside or inside dimension? If it's the outside, it's going to be tougher to get a 6" insulated liner down later.

Make sure you can insulate the liner later on, i.e. leave enough space.

I think therefore why put a terracotta liner in there at all? Just have it capped with a solid slab. They can cut a hole later when you are installing an insulated liner? (But my cap knowledge is not great... So I may be saying something stupid.)

 

[begreen]

I think therefore why put a terracotta liner in there at all? Just have it capped with a solid slab. They can cut a hole later when you are installing an insulated liner?

I agree with bholler. It looks well maintained, just not safe for fire. At this point, it doesn't look like anything need be done. If the intent is to plan for the future a blank stainless (or copper) cap could be put on for now. If liners go in, I wouldn't do terracotta. Instead, I'd have 2, insulated, stainless steel liners put in and they would be 6" which covers most modern wood burning appliances.

Seeing this is a garage, check with the insurance company first. They may flat out say no for a wood stove in any place where gas powered equipment is located. However, that may only apply to the first floor. Check with them and the inspecting authority before investing.

 

[mnowaczyk]

Thanks guys. TerraCotta seems like the cheap and fast option to get work done early this week. I guess if there’s a way to just put in and support a small piece of terracotta or other liner at the top of the chimney so we can build the cap, that could be sufficient. Maybe I just buy 1-2 pieces of terracotta or heck, even some 8” round Galvanized duct work to only put at the top right now makes the most sense. That can enable us to build the concrete cap but still get into the chimney easily later. I’d prefer to not have to cut a cap in a few months or years after pouring it this week. Hmm…

Two 8” round galvanized duct work with an and cap on each to keep water out might be all I need.

 

[begreen]

Even with a terracotta liner an insulated stove liner would have to go in to be code-legal for a woodstove. The chimney does not have the required 2" clearances from combustibles that is required. This needs more thought and planning or it will be money wasted.

 

[stoveliker]

The point is you can add a cap/slab/metal sheet closing the whole thing off *without* a (terracotta or other) liner.
Cheapest option with all future options still open.

Just put a slab on top of the brick and be done for now.

 

[bholler]

Thanks guys. TerraCotta seems like the cheap and fast option to get work done early this week. I guess if there’s a way to just put in and support a small piece of terracotta or other liner at the top of the chimney so we can build the cap, that could be sufficient. Maybe I just buy 1-2 pieces of terracotta or heck, even some 8” round Galvanized duct work to only put at the top right now makes the most sense. That can enable us to build the concrete cap but still get into the chimney easily later. I’d prefer to not have to cut a cap in a few months or years after pouring it this week. Hmm…

Two 8” round galvanized duct work with an and cap on each to keep water out might be all I need.

You are really over thinking this. A crown with 2 8" holes formed in it would be fine. A stainless top plate is probably what I would do though