Do you think this will work? Fireplace draft

[Michael6268]

I have an excessive draft problem in my area. We use an open fireplace a couple times a week and have been battling the draft problem for years. Heat the house coal so let me say, im not trying to heat the house with the fireplace and know it is a waste of $$ as far as heating dollars are concerned. Ive experimented with closing the throat damper without much success. Seems that to make any difference I have to close it so much that I end up getting smoke in the house. Ok , what I have is a 12x12 inner dia. masonry, clay lined chimney. Today I went up on the roof, removed the chimney cap and installed a piece of 24gauge sheet metal on top of the last chimney tile blocking more than a 1/3 but less than 1/2 of the flue tile, and reinstalled the cap. I was a little worried if smoke may back up now so I just lit a bunch of newspaper and made a lot of smoke and no problem with smoke back up. Wont be trying with a fire till tonight. Can anyone think of any problems with doing this and do you think it will help my excessive draft problem? I know they make top mounted dampers. If this works I might consider istalling one next year.

 

[webbie]

In most cases, I don't see this doing any harm - it is a normal thing that a lot of chimney caps and chimney pots end up closing off 1/4 to 1/3 of the flue area - and, as you mention, top sealing dampers do the same.

In a worst case scenario it would be possible that with a poor chimney (cracked tiles, spaces, poor masonry), closing off the top could force some smoke out those cracks. However, if you see plenty of draft at the bottom this seems unlikely. Most fireplaces are just built...without thinking exactly about draft, so it would be natural for many to over over-draft and many to have under draft.

 

[Michael6268]

Well first fire was a smashing success! My experiment seemed to work out great. For the first time in five years I wasn't adding wood every 15 minutes while the house was getting colder, and the fireplace actually threw out some decent heat for a fireplace! Also noticed that due to the slower draft that we didn't feel the cold air rushing past us up the chimney, and the temp in the house didn't drop like it normally did due to the excessive amounts of air rushing up the chimney! In the past the house temp would go from 73 to 69 in about a half hour or so. Last night it actually went up a few degrees!

 

[begreen]

Sounds like a classic case of TMD.

(too much draft)