View Full Version : Taking down a cinder block chimney safely.
carubah
Feb 5, 2009, 07:47 AM
I need to take down our free standing, against the house, cinder block chimney, with a clay liner.
The house is a 1 1/2 story house. The Chimney is located close to the peak of the roof area.
There is about an inch space between the chimney and the house.
Right now I have metal straps attaching it to the house to stabilize it.. which can be taken off and then the chimney would be 'unstable' enough to push over, I think? But how to go about it is the question I have?
Do I chisle partway down the chimney to loosen the top section of blocks and then try and remove that top section first?
Or with the clay liner would it be impossible for the cinder blocks to free from the liner and not work?
There are fruit trees also in the line of where the chimney would fall.
I would appreciate any help with this!
Thank you, Don
ballengerb1
Feb 5, 2009, 10:12 AM
The safest way is to remove the chimney block by block. It sounds like you are hoping to just push it over and that is not a safe approach.
KISS
Feb 5, 2009, 12:06 PM
Well, if I were to do it, you would need:
1. A wide chisel and mallot
2. An impact drill or tool.
3. A cutting wheel on an angle grinder.
I had to remove a couple of courses on a brick chimney, but the cement was damaged.
21boat
Feb 5, 2009, 01:45 PM
Be careful here carubn
I would like to add here. Taken quite a few down already.
I see a possible accident here that wasn't mentioned yet.
If that chimney has a gap already and now it's a floating chimney, the two straps aren't enough for safety.
Once you get the block down past the first strap then that next part of the chimney is unstable and if that lets loose and rips the lower strap out, the chimney could hit the scaffolding and you can fall with scaffolding chimney and all,
Add a couple of more straps to stabilize that middle section.
Set the scaffolding up to the roof line and use plumber's strap form scaffolding to roof rake. If something did happen then the scaffolding is also stabilized.
The best tool to use is a demolition hammer from a rental store. Something equivalent to a Bosch 11305
Bosch 11318EVS Demolition Hammer (http://www.drillspot.com/products/76645/Bosch_11318EVS_Demolition_Hammer)
A chisel and hammer will take to long. The mortar is most likely good and tuff. It's the footer that was to small from the house out for a free standing chimney. A coupe of masonry ties won't hold a chimney if the footer is bad or undersized. 90% of most block chimneys develop a gap because of footer problems.
It will be tempting to push it over but if you do the bottom can bind against the house and damage it.
I have saw cut the bottom like a tree and pulled them over but you need to know what to look for and as a novice do it by the block.
At 12 feet of chimney 1 1/2 story you have about 19 courses of block. A 16x16 chimney block weighs about 63lbs with its mortar. An 8x8 flue weighs 32 lbs a piece so that's 192 lbs in flue at 12 feet and 1,197 lbs in block total is 1,389+ in total weight. I did this caluc for you in case you need to haul it away in a pickup so you know the load.
Signed 21 Boat
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