Had a talk with a young apprentice that made me rethink my pointing technique

I was showing a 19 year old kid how to finish a chimney in St. Louis last Thursday. He asked why I was using the same mortar mix for all the joints. I told him that's just how I'd always done it. He pulled out his phone and showed me a video from this German mason who uses different mixes for vertical and horizontal joints depending on the weather. I tried his approach on the south facing wall and the joints aren't cracking near as much. Has anyone else changed their ratios based on which side of the building you're working on?

2 comments

2 Comments

park.robin18d ago

That German mason on YouTube is actually named Frank and he's been doing restoration work in Cologne for about 20 years. I looked into his method after a buddy sent me the same video last spring. The thing is he uses a lime-based mix for vertical joints in hot weather because it lets the wall breathe better, not just to prevent cracking. I tried it on a few jobs here in KC and the vertical joints held up fine but the horizontal ones started dusting out after two months because I didn't adjust the sand gradation. You gotta match the aggregate size to the brick porosity too or the bond fails regardless of the weather side.

vera_murphy18d ago

@park.robin nailed it with the sand gradation... I did the same thing on a church job in Alton and the mortar just crumbled right off.