Y⃒̸̷̝̜̙ͥͥͥngmar

It worked! We've had a few heating/cooling cycles now and the crack stays gone. There's a few hairline cracks in the surface but those are just from the heat drying the limewash out too fast and a second coat (applied when cold) should get rid of them too.

Thanks to whoever suggested this. Can't remember who, maybe @valentinzi?

#Chimney #Crack #Repair #DIY #Lime #Limewash #Homestead #Sauna

Sep 25, 2025 at 1:01pmWeb
Show threadvalentinziSep 30, 2025
For crack repair, I used a hydraulically setting chamotte mortar. (It is important that the material has a similar composition to the bricks). For small cracks, I use a very fine grain size, for larger cracks a slightly coarser (still fine) grain size. It is important to open the crack wide with high temperatures, make it slightly larger at the edges, remove dust and loose parts. Then I poke and press the mortar (while it is still hot) into the cracks with a very thin spatula (always in approx. 5 cm steps, otherwise the mortar hardens too quickly). I only use lime mortar for plastering (where temperatures do not exceed 200 degrees). Sometimes it takes several steps to close the crack. But small hairline cracks are not a big problem. I'll finally get around to plastering my oven in the next few days (weeks).