If the thimble is slightly cracked you should go ahead and repair it.
Chimney thimble replacement.
A thimble should be cemented with high temperature cement into the masonry wall of the chimney and the stovepipe inserted into the thimble without cement for easy removal for cleaning and replacement.
To do it you need to mix mortar to a fairly watery consistency to be able to easily work with it into the cracks.
Single wall stove pipe going from the stove to the chimney must have a minimum of 18 clearance to combustibles.
180 degree heat shields are available for single wall pipe to reduce clearances to 6 for walls and 9 to the ceiling.
You should pack insulation snugly against the outside box frame of the thimble but never place insulation into the area within the thimbles s cylinder.
If you can in stall a clay thimble y.
Installing a thimble in a chimney isn t difficult but the job needs to be approached carefully and systematically to avoid damage to the interior chimney flue.
For ideal results you should fill the cracks from both the inside and outside of the thimble.
Wood stoves use thimbles made of clay to handle high temperatures a the junction between the wood stove and the chimney.
Things you ll need refractory mortar trowel putty knife hammer chisel.
The proper way to close off a thimble port is with brick and mortar to create a solid and safe enclosure.
If there s no lining due to the flue then a new one needs to be installed.
How to replace the chimney thimble.
The thimble enters the flue inside the chimney at a 90 degree angle and is designed to accommodate the entry of a stovepipe from a wood stove.
If the stovepipe is connected to a masonry chimney it should extend through the near wall of a chimney to the inner face of the chimney liner but not beyond it.
The duraplus system from duravent is designed to the duraplus system from duravent is designed to stay cool on the outside provide a hot draft on the inside and boost stove efficiency offering a fire safe design that protects both the chimney and building.
It s important that your chimney service technician checks that the area that gets closed off has a lining.
