Hello.
I have a 1.5-story 1960s house with a brick chimney located at the gable (half of the chimney extends into the house and half extends outside the outer gable).
Part of the chimney goes through the side attic, and that part has recently been told by the chimney sweep that I need to plaster in order to use it for burning. The other parts of the chimney facing the furnished part of the house appear to be plastered and then covered with gypsum (I think), as far as I can see from the side attic.
Do I really need to do this? What is the danger? The part of the chimney that goes through the side attic has lots of airspace around it, and nothing flammable is against the brick.
And if it were the case that the parts of the chimney that are against interior walls are not plastered, I can't access it anyway (even though it looks like in the places I can see, it is plastered).
Is the chimney sweep being overzealous? What does the law say? Is there any fire risk with an unplastered chimney side in the side attic??
I have a 1.5-story 1960s house with a brick chimney located at the gable (half of the chimney extends into the house and half extends outside the outer gable).
Part of the chimney goes through the side attic, and that part has recently been told by the chimney sweep that I need to plaster in order to use it for burning. The other parts of the chimney facing the furnished part of the house appear to be plastered and then covered with gypsum (I think), as far as I can see from the side attic.
Do I really need to do this? What is the danger? The part of the chimney that goes through the side attic has lots of airspace around it, and nothing flammable is against the brick.
And if it were the case that the parts of the chimney that are against interior walls are not plastered, I can't access it anyway (even though it looks like in the places I can see, it is plastered).
Is the chimney sweep being overzealous? What does the law say? Is there any fire risk with an unplastered chimney side in the side attic??
I don't know the rules for this, but a plastered chimney is denser and thus reduces the risk of fire.
It's common for the chimney not to be plastered where it isn't visible, such as at a floor joist. That is where it most needs to be plastered due to fire risk.
It's common for the chimney not to be plastered where it isn't visible, such as at a floor joist. That is where it most needs to be plastered due to fire risk.
mats_o expressed it more accurately; of course an unrendered chimney can be sealed, but the risk of it not being sealed is greater than for a rendered chimney.
As I said, I don't know the rules, but it's a reasonable point; there have been some fires due to unsealed unrendered chimneys.
As I said, I don't know the rules, but it's a reasonable point; there have been some fires due to unsealed unrendered chimneys.
I made a three-channel brick chimney in our new house. The chimney sweep said that all edges indoors must be plastered. (then it was as tight as a steel pipe)
As someone wrote earlier, a plastered chimney is tighter than an unplastered one.
Mix the plaster, take a brush and a bucket of water up. Moisture the bricks a bit by tossing water with the brush. Then it's just a matter of throwing on the plaster. If you want to get a bit of an old style, let the plaster dry a little 10-30 min depending on the temp, then brush the plaster with the wet brush.
There are some pictures in the blog http://www.byggahus.se/bloggar/malmborg
As someone wrote earlier, a plastered chimney is tighter than an unplastered one.
Mix the plaster, take a brush and a bucket of water up. Moisture the bricks a bit by tossing water with the brush. Then it's just a matter of throwing on the plaster. If you want to get a bit of an old style, let the plaster dry a little 10-30 min depending on the temp, then brush the plaster with the wet brush.
There are some pictures in the blog http://www.byggahus.se/bloggar/malmborg
Hello,
As a note, it can be mentioned that combustible building parts near the chimney must not be exposed to temperatures over 85 degrees C. This is because wood exposed to elevated temperatures for extended periods increases its gas absorption. Naturally, drying also occurs. In other words, you get wood that is dried out with an increased oxygen content. Under these conditions, ignition can occur at just 100 degrees C...
It's because of this that a single spark can be enough to ignite wood near a chimney.
Regards,
Wasa
As a note, it can be mentioned that combustible building parts near the chimney must not be exposed to temperatures over 85 degrees C. This is because wood exposed to elevated temperatures for extended periods increases its gas absorption. Naturally, drying also occurs. In other words, you get wood that is dried out with an increased oxygen content. Under these conditions, ignition can occur at just 100 degrees C...
It's because of this that a single spark can be enough to ignite wood near a chimney.
Regards,
Wasa
Well, I have polished it now and got approval from the sweep before Christmas. It's nice to be able to light a fire.
What's a bit unsettling is that you don't know if there's wood next to the chimney in places you can't see, like floor joists and the parts of the chimney that form interior walls. You don't know how careful they were in the '60s when they built the house.
The chimney is pressure tested and sealed anyway, plus I've applied plaster to the attic section of the chimney.
Interestingly, the sweep said that the regulations only care if there's load-bearing wood next to the chimney. According to him, it's OK according to the regulations to have non-load-bearing wood in contact with the chimney. It seems a bit strange, one might think.
What's a bit unsettling is that you don't know if there's wood next to the chimney in places you can't see, like floor joists and the parts of the chimney that form interior walls. You don't know how careful they were in the '60s when they built the house.
The chimney is pressure tested and sealed anyway, plus I've applied plaster to the attic section of the chimney.
Interestingly, the sweep said that the regulations only care if there's load-bearing wood next to the chimney. According to him, it's OK according to the regulations to have non-load-bearing wood in contact with the chimney. It seems a bit strange, one might think.