Crown Repair in preparation for now Wood Insert

[racingmason23]

I am a longtime lurker here who finally decided to get a new wood insert to replace the old 1980s Black Bart that was rusted to hell. I had a chimney company come out and do an inspection for our new insurance company per our policy. I knew when we purchased the house 6 years ago that during heavy / blowing rain, a small amount of water would get into the flue and down into the insert, but noting I was concerned about until this month when we got heavy rain and the insert had over a quart of water in it. The inspection came back as not to use and a whole list of repairts. The cost to line the chimney with an 8 inch liner, retrofit the stove, and upgrade the fan, is more than a new unit with the tax incentives. One thing that was identified was the crown had some cracking on it an the repair from the previous owner was where the leaks were coming from. The quote to cut out the old crown and redo it was outrageous, which I could expect as we are in a small town with only one chimney service company. I plan on removing the old crown, the top 12x12x18 flue tile as it is cracked, and removing the mortar on the top row of bricks as it's lifted from many freeze-thaw cycles here in the South.

As far as I can tell, this mortar and crown are original to the 1969 construction of the house. I plan to form and pour a concrete cap that will overhang 1.5 inches on all sides, leaving an expansion joint around the new flue tile and sealing with silicone, fixing the mortar, and then water sealing the brick. How tall should I leave the new flue tile I'm putting in to replace the cracked one?

 

[Ctwoodtick]

I’m planing on DIY’ing a chimney crown like yourself hopefully this Spring. Out of curiousity, what were they quoting you on that?

 

[racingmason23]

I’m planing on DIY’ing a chimney crown like yourself hopefully this Spring. Out of curiousity, what were they quoting you on that?

$1000 for the crown not including new cap and flue replacement/extension. I have all the tools to remove and do the work and have done enough concrete on other home projects I feel comfortable doing it. Its a one story house with a 6/12 pitch room so pretty easy to get 6-7 bags of mix up there.

 

[Ctwoodtick]

$1000 for the crown not including new cap and flue replacement/extension. I have all the tools to remove and do the work and have done enough concrete on other home projects I feel comfortable doing it. Its a one story house with a 6/12 pitch room so pretty easy to get 6-7 bags of mix up there.

I bet you will do a much better job too.

 

[racingmason23]

I bet you will do a much better job too.

I am meticolous. Trying to decide if I should remove the top course of bricks since that is what forms the current drip edge.

 

[bholler]

I am meticolous. Trying to decide if I should remove the top course of bricks since that is what forms the current drip edge.

I probably would. It will look better. Do a bond break under the crown as well. I just use a sheet of plastic

 

[Ctwoodtick]

I probably would. It will look better. Do a bond break under the crown as well. I just use a sheet of plastic

Do you need to put anything under the sheet of plastic to prevent the weight of the wet concrete from caving the plastic in?

 

[bholler]

Do you need to put anything under the sheet of plastic to prevent the weight of the wet concrete from caving the plastic in?

Well yeah it needs supported somehow