Transformed by summer our site is a birdsong filled paradise. We take up where we left off in rainy February, to erect the pair of fireplace pillars.
Carefull preparation back in February has paid off, with the pillar positions already marked at half a foot below floor level.
Now they are wedged at the base with smaller stones and mortar, which is how the original structure was except that it was secured into the foundation by mud only.
Jambs built to each
side support the pillars.
Useful in their repositioning are weathering marks, showing where the stones met the floor, and the depth at which they were tied into the wall.
The inner hearth has a gentle elliptical shape, which the lads expertly build.
After the buttresses have been cleaned of old cement, they are lifted atop the pillars.
limewindow 
What are the thoughts on lime withstanding heat in a hearth? Old fireplaces & chimneys were lagged with a 50/50 mix of blue till & cow dung which was said to set hard and prevented seepage of soot. The same mix is used in India though the clay there is different.
Allan
Structurally the chimney interior shall differ, supporting/enclosing the clay flue (8’’) pipe, with an insulating (2’’) dry sand and lime mixture packed around it. Modern flue insulators are supposedly not that effective anyway. The clay pipe comes in sections and it needs two bends in it, for a better draw. I also heard about mixing hemp into the lime render (interior) for insulation – must research it!