42" Neapolitan oven in SW Ohio

[buckeye_brian]

OK...after a long discussion with a masonry contractor on my jobsite...he suggested I top off the fire brick chimney base with solid 4" x 8" x 16" concrete block. He said (like you David S) to NOT USE the flue liner. I was asking for problems down the road. I have probably 15 - 20 more fire brick on hand. I will use them up and top off with solid concrete block to get my 4' height. Then I will go around it with my historic red brick.

Side note: I work for a developer / construction / real estate company in Cincinnati. I have been restoring circa 1850 - 1870's buildings in the Over-the Rhine section of the city for the last 10-years. They call it OTR because it is the section of the city that was settled by German immigrants in the early / mid 19th century. The Erie Canal used to split Cincinnati in half. The Germans called the canal the "little Rhine" after the Rhine River in Germany. The canal was replaced by Central Parkway in the 1930's (I think), but the name OTR stuck. I have been collecting bricks for years to use on my Man-Kitchen from the buildings we restore. I actually have all the brick from a bakery oven that was built in 1848 on Elm St across from Findlay Market. One of the oldest continually operated markets in the US (opened in 1852). The bakery operated almost 100-years but had to close in the early 1940's do to threats by the populace because they were "German." I guess no one like the Germans in the early 1940's...go figure. I did not trust the firebricks to use as "firebrick" but I will find a use for them someday.

So what do you think about my solid concrete block idea? I think it will only be one course at the top of the 48" +/- chimney.

[david s]

If you insulate around the outside of the flue liner, it will prevent it from cracking. It is the difference between the inside and outside temperatures which sets up a difference in thermal expansion that creates the problem. The insulation fixes this problem.A solid concrete block is a different story. The Portland cement can’t handle high heat and may crack in that position. I’d be sticking with the insulated flue liner, surrounded by the historic clay bricks and skipping the stainless flue.