Fire protection around chimney with insert stove?

[Sir Duke]

Hi everyone!

I'm thinking about installing a stove in an existing chimney. I believe it's called an insert stove. Do you need to fireproof around the entire chimney at floor level? There is parquet flooring there now. Can you place a glass or metal sheet on top of the wooden floor? However, as mentioned, it doesn't really spark on all four sides of the chimney. But should you also consider the heat from the chimney?

 

[Tombrittberg]

Hello everyone!

Planning to install a stove in an existing chimney. I believe it's called an insert stove. Do I need to fireproof around the entire chimney at the floor level? There is parquet flooring there currently. Can I place a glass or metal plate on top of the wooden floor? But as mentioned, embers don't scatter on all four sides of the chimney. But do I also need to consider the heat from the chimney?

Hello Sir Duke.
I don't quite understand your situation, do you have an open fireplace that you're planning to insert an insert into?
Or are you planning to place a stove directly on the floor?
Either way, it should come with a mounting guide.
Protection for the floor is measured from the stove's firebox opening.
You have to consider combustibles along the entire length of the chimney.
Feel free to provide a bit more info about the house and stove etc.

 

[Sir Duke]

Hello! No, it is not an open fireplace, it is a closed plastered chimney. There are internal channels for ventilation and to release exhaust gases from the former wood and oil boiler in the basement. Therefore, I am considering installing an insert stove. This will be placed perhaps half a meter up from the floor. Is it still inappropriate to have wooden flooring around it?

 

[Tombrittberg]

Hello!
No, it's not an open fireplace, it's a closed plastered chimney. There are channels inside for ventilation and to release exhaust gases from the previous wood and oil burner in the basement. Therefore, I'm thinking of installing an insert stove. This will perhaps be placed half a meter up from the floor. Is it still inappropriate to have wooden flooring around it?

You must cover the wooden floor, call the chimney sweep and find out what the regulations are.

 

[AndersS]

If I remember correctly with the insert we have, it was 30 cm in front and 10 cm on the sides where there should be non-combustible material. A plate on the floor is a solution.

 

[AndersS]

Here is Boverket's text, where I have bolded.

5:4223 Hearth floor Fireplaces for burning solid or liquid fuels must be equipped with protection against downward fire spread to prevent floor ignition due to spills, embers, or sparks. General advice Protection against downward fire spread is fulfilled if floor covering or hearth floor is constructed in at least fire technical class A2-s1,d0. If there is a free space under the fireplace or hearth base, the hearth floor should also cover this area. The hearth floor for boilers fired with solid fuels should be at least 2 meters in front of the side with the fireplace opening and at least 1 meter outside the other parts. For smaller, enclosed fireplaces, the hearth floor should extend at least 0.3 meters in front of the fireplace and at least 0.1 meters on each side of the fireplace or have at least 0.2 meters additional on each side of the opening. For larger enclosed fireplaces (such as tiled stoves), the extension sideways can be limited to the width of the fireplace opening with at least 0.2 meters additional on each side of the opening. For open fireplaces, the hearth floor should be arranged so that the horizontal distance from the center of the rear part of the fire to unprotected combustible floor is at least 1.0 meter. From a larger open hearth, the hearth floor should also always extend at least 0.3 meters in front of the fireplace. If the hearth base is higher than 0.4 meters above the floor, the distance should be increased by half of the excess height measurement.

 

[Sir Duke]

Thank you all, great info!
What I was really looking for is whether it was prohibited to have wooden floors, both as subflooring and top flooring. Not because of embers directly from the stove, but because the chimney gets warm when you burn and it could be a risk if wood was directly against it. But it seems to be okay then. Wooden floors right up to it with some plate on top against embers.

 

[Stefan1972]

Though it sounds like there is some confusion here? If you don't have a fireplace today, then you shouldn't get an insert stove but rather a freestanding one that you connect to a chimney using pipes.

 

[Sir Duke]

Aha, I just call it insert but maybe that's wrong. But the stove is supposed to be built into the chimney. Is it called a cassette maybe?

 

[Stefan1972]

Ah, I just call it insert but that might be wrong. But the stove is supposed to be built into the chimney. Maybe it's called a cassette?

Yes, but you can't mount such a thing into a chimney in that way. The chimney is a straight pillar with channels in it. If you want an open fireplace, it's built to the side and in that, you can have a cassette/insert stove. Or a tiled stove. Or a freestanding stove.
You can't chip away at the chimney and think you can embed an insert into it. Where would the channels go, then?

 

[Sir Duke]

Understood, but I have 8 channels, of which only 2 are used for ventilation today. No longer any connected boilers. I've had two companies here who have looked and calculated and offered to install a fireplace inside the chimney.

 

[Tombrittberg]

Understood, but I have 8 channels, of which only 2 are used for ventilation today. No boilers connected anymore. I've had two companies here who have looked and calculated and quoted on installing a stove inside the chimney.

I think it's a complex project you're starting. You're dealing with substantial weight, especially if you remove 50% of the chimney. But it's interesting with unusual tasks. Feel free to update with ongoing posts and maybe some pictures of the project.

Good luck.

 

[ylven]

Do you mean that you intend to connect a stove to the chimney? Or that you plan to hollow out the chimney and place a stove inside it?
If you only plan to connect a stove to the chimney, it is not a complicated job. You just need to drill a hole in the chimney to connect the flue pipe, lay out a hearth (e.g., a glass panel or sheet metal) underneath and in front, and ensure there is nothing combustible at an unauthorized distance (you can easily shield this with a sheet or board of fireproof material with air behind it).

The flue needs to be tested for tightness, preferably beforehand, so there are no unpleasant surprises when it's time for inspection. Considering that there have been fireplaces connected to the chimney before, there should not be a problem with combustibles too close (such as inserted) to the hotter parts of the chimney.

 

[Sir Duke]

I think it seems like a complicated project you're starting with. It's quite a heavy task you're dealing with if, for instance, you remove 50% of the chimney. But it's interesting with unusual assignments. You can keep us updated with ongoing posts and maybe some pictures of the project.

Good luck.

Thank you!
Of course, it will be professionals who do the work. Those who have been here to look have been optimistic. They're going to carve out the chimney but not the whole thing, just a corner. They say they first drill several through holes above and then insert iron rods to bear the load.

 

[Sir Duke]

Do you mean that you are going to connect a stove to the chimney stack? Or that you are going to hollow out the chimney stack and place a stove inside it?
If you're just going to connect a stove to the chimney stack, it is not a complicated job. You only need to drill a hole in the chimney stack to connect the flue pipe, lay out a hearth (e.g. a glass plate or sheet metal) underneath and in front, and ensure that there is nothing combustible at an impermissible distance (this can be easily screened off with a plate or sheet of fireproof material with air behind it).

The flue needs to be tested for tightness, preferably before, so there are no unpleasant surprises when it's time for inspection. Considering that there have been fireplaces connected to the chimney before, there shouldn't be issues with combustibles too close (like inserted) to hotter parts of the chimney.

Thanks for the input!
The stove will be inside the chimney stack.
Professionals will be doing the work.
They will use slip casting on the channel so it's tight.