Is it safe to plug my fireplace?

Submitted by thecosmicradiation t3_yh0pbk in DIY

Hi there,

I'm living in an old villa and my bedroom has an unused fireplace. This has not been fully blocked off - instead the landlord has covered it with black plastic and sealed the edges with tape. I can hear the plastic shift and crinkle with the breeze blowing in down the chimney.

My question is, is it safe for me to more effectively cover this fireplace? I would probably shove a rubbish bag stuffed with newspaper up the chimney, or maybe an old pillow, and cover the front face entirely with an old blanket or sheet. Google tells me that you need to keep a good airflow going in the chimney to prevent condensation - will blocking the chimney in this way cause a problem there? Or is it okay because the air can still come in from the top, and I'm just blocking its entry into my room?

I've also heard of chimney balloons or dampers, but I just need a cheap option, doesn't matter if it's ugly.

This fireplace will never be used, but I'm not allowed (and can't afford) to have it and the chimney dismantled.

Edit: image of the fireplace is here: https://imgur.com/xIAwInJ

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Comments

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No_Coyote_ t1_iubgj6e wrote

Just stuff some fiber glass batt insulation up into the flu. Easily removable when your lease is over.

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thecosmicradiation OP t1_iubkb9x wrote

Will blocking the flue cause any issues with condensation?

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No_Coyote_ t1_iubo5oi wrote

Looks like an old house and not very airtight. I don’t think condensation would be any issue whatsoever.

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thecosmicradiation OP t1_iubwmya wrote

It is an extremely old house. Right now the airflow doesn't bother me so much because we're coming into summer but I imagine in autumn I'll want to block it more effectively.

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MidnightAdventurer t1_iucjvwd wrote

Condensation seems unlikely to be a significant issue. The only major issue I can see is if rain gets in the top of the chimney and you get a whole lot of water in there. Whether or not this is possible very much depends on what the top looks like
Is it safe for you to access the top of the chimney and put a cap over it or otherwise block it from the outside?

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PerspectivePure2169 t1_iubyr9y wrote

You don't want to use fiberglass batt for this. It's permeable and a chimney has a powerful draft effect even without a fire. It will still leak and will probably get wet and moldy.

You can always spot where the air leaks are in tops of walls up in attics because the fiberglass insulation gets filthy there. It's just an air filter in that case.

Chimney balloons are cheap and effective. Rigid foam insulation spray foamed into place is even better. Whatever it is should be damp proof and air impermeable.

For OP, there will still be enough air movement for the brick to dry itself above the plug if you do this fix.

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_catkin_ t1_iuddru7 wrote

Make sure it’s visible. If someone tries to use the fire with it blocked up, no bueno.

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draftstone t1_iudrytp wrote

Also, if anyone ever buy a house with a chimney, get it fully inspected and cleaned up before using it. You have no idea if the previous owner was safe or not and it is a really dangerous fire hazard if you start a fire in a chimney that you have no idea is safe.

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musofiko t1_iuejzwv wrote

Ask the land lord to tarp the top of the chimney or put a temporary seal on it as the noise keeps you up.

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musofiko t1_iuekntj wrote

Just shove a tarp up there if you need to do it yourself water will still drain around the edges and anything that is pooled won't be much, it won't be letting huge amount of air through which is the main thing. I am Australian and we are known for easy solves with zero fucks for looks.

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