How to Block a Chimney

How to Block a Chimney

You may consider blocking your chimney or fireplace due to several reasons. There can be a leak in the chimney, or you may be getting cold air from the fireplace. Also, the chimney is the big reason for escaping of cold or hot air from your home. Because of these reasons, many homeowners want to seal the chimney for some time or permanently. If you want to block your chimney and don’t know how to do that, then here are some simple steps to help you. 

  • For blocking your chimney temporarily, you will need to visit your roof and inspect the chimney first. If required, ask a professional for inspecting the chimney and cleaning it before blocking it.
  • After that, remove the chimney cap and measure all sides of the chimney. Now, wear heavy gloves and cut a piece of sheet metal as per the size of the chimney opening.
  • Then take a bead of butyl rubber and apply it around the chimney opening. After that, place the metal piece on the chimney opening.
  • Compress the metal piece into the rubber bead. Then put back the chimney cap and fully close the fireplace damper.
  • Now, measure the sides of the chimney opening below the damper. Cut a piece of rigid foam insulation as per the measurement done.
  • Then place the foam piece inside the chimney tightly. Take a bead of butyl rubber and apply around the sides of foam insulation.
  • Once the blocking is done, it will block the rain. But if you seal the chimney completely, then the moisture of your home can’t escape and cause decay.

This is a simple method of blocking your chimney. If you want to use the chimney again, then you can conduct a chimney inspection before doing that.
Now, you might be thinking that why it is dangerous to seal a chimney completely. Here is the reason.

Why Sealing the Chimney Is Not Safe?

When the chimney is fully sealed, and someone makes a fire in the fireplace, your home will be filled with smoke. Although this is not dangerous, it can cause inconvenience. If there are gas logs in the fireplace, then there is a danger. In some homes, people use the blocked chimney without noticing that it is blocked. This will increase the heat inside the chimney and cause carbon monoxide poisoning.

Moreover, a blocked chimney experiences different temperatures, which cause the moisture to condense and form liquid inside the chimney. Over time, this will increase and let more water enter your home. Also, the creosote, heat, and smoke won’t escape from your home, and they will find their way back to your home. This will damage your home decors and cause breathing issues.

Therefore, you can consider seal a fireplace temporarily, as explained above, instead of blocking it completely.

How To Block A Chimney Permanently?

If you are not going to use the chimney again in the future, then you can consider blocking it permanently. To do that, you can dismantle the chimney and build a roof over that. However, most people don’t follow this because they want to reopen the chimney in the future. That’s why most people follow the above method to block the chimney safely so that they can open it when needed.

Therefore, the temporary solution is better than the permanent one. So, you should follow that method for blocking your chimney.

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