Old coal chimney

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  #1  
Old 09-29-18, 04:26 AM
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Old coal chimney

There is an old coal chimney flue over 3 floors in our house (built 1910).
i want to remove the flue bit am not sure if I have to remove the chimney as well?
Does the brick work in each floor support the chimney or is the chimney only supported up on the roof?
Can I knock out this square wall in each floor and then just cap the flue?
 
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  #2  
Old 09-29-18, 05:12 AM
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The support for the chimney starts at the ground/basement. A chimney gets removed from the top down. If you take out a middle portion you run the risk of the brick above collapsing.
 
  #3  
Old 09-29-18, 07:15 AM
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If I was to remove the chimney first then, what's the best way to waterproof?
I would need some support underneath the new roofing material to cover?
 
  #4  
Old 09-29-18, 08:20 AM
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1. Remove the chimney.
2. Patch the hole with the necessary framing and roof sheathing.
3. Install roofing felt and new shingles in the patched area.

Be sure new shingles at the top row are underneath the row of old shingles above.
 
  #5  
Old 09-29-18, 08:23 AM
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If the layer is underneath then doesn't that allow water in? I would have thought the new felt would go on top of the old one with the roofing adhesive.
 
  #6  
Old 09-29-18, 09:04 AM
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A little hard to tell from the pic, is it a flat roof or does it have a low slope?
 
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Old 09-29-18, 09:05 AM
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Low slope to one area with a drain on one side.
 
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Old 09-29-18, 09:13 AM
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The high side of the patch should be underneath the existing roofing, the rest would be on top.
 
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Old 09-29-18, 10:25 AM
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I still don't get it
So, I have to lift up the current felt and then slide in some felt patch so it's underneath, then adhesive?
To me that just seems like it would let water in. Why not put the patch on top of the hole and existing membrane?

Or do you mean because I'm folding in that membrane where the chimney is now?
 
  #10  
Old 09-29-18, 11:16 AM
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If water is running down hill you don't want it to intersect with a patch that is above the rest of the roof. When the adhesive fails the water will find it's way under the patch. If the patch goes all the way up to the curbing it won't need to slide under the high end.
 
  #11  
Old 09-29-18, 03:31 PM
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Originally Posted by marksr View Post
The support for the chimney starts at the ground/basement. A chimney gets removed from the top down. If you take out a middle portion you run the risk of the brick above collapsing.
https://www.youtube.com/watch?v=HF1pHzGkSC4
 
  #12  
Old 09-30-18, 03:05 PM
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If water is running down hill you don't want it to intersect with a patch that is above the rest of the roof. When the adhesive fails the water will find it's way under the patch. If the patch goes all the way up to the curbing it won't need to slide under the high end.
Understood though isn't it the same if the patch is under? All patches need adhesive and if the patch is under, it acts like a little area that catches water...like a mini flat basin?

Also, the roof has a type of grey gravel on it. Is this a tar roof or a membrane roof? I thought the gravel only went on tar?
 

Last edited by qwertyjjj; 09-30-18 at 03:55 PM.
  #13  
Old 10-06-18, 06:33 PM
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So, if I put framing in place to fill the hole, what do I patch with? Felt? and elastomeric coating or just an amount of plastic cement? Is there any need to throw grey gravely bits over like there is at the moment or just leave as a piece of black felt?

I think what we have is TPO membrane or elastomer
 
  #14  
Old 10-07-18, 02:18 AM
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I'm not a roofer but you need to install plywood over the framing/hole. I'd at least cover the felt with elastomeric or roofing tar. I wouldn't be overly concerned about making it blend visually.
 
  #15  
Old 10-07-18, 05:30 AM
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Over the hole or underneath it for the wood?
i assumed the finish would be flat. If the plywood goes over the hole then there will be a little 3/4" raised lip to put the felt over, then tar over the felt?
 
  #16  
Old 10-07-18, 05:50 AM
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Install your framing so the plywood will set flush with the surrounding decking.
 
  #17  
Old 10-07-18, 10:56 AM
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Do I need felt at all or can I just cover the plywood in elastomeric coating?
 
  #18  
Old 10-07-18, 04:09 PM
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I'd use felt. If you forgo the felt you'd need some sort of membrane embedded in the elastomeric.
 
  #19  
Old 10-07-18, 06:48 PM
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And can I just leave the felt there or does it really need to be covered with some sort of gravel or shingle?
 
  #20  
Old 10-08-18, 01:51 AM
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The felt needs to be covered. Shingles [your roof is likely too flat for shingles] roofing tar or an elastomeric coating.
 
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