Replacement of individual clinker bricks - Which mortar mix to use?

Hello everyone,

Question for you specialists:
We are converting an old barn into an apartment. We have partially lowered "normal" windows to floor-to-ceiling windows. That means some bricks have been removed. I drilled out the joints with a drill, removed the bricks, and chipped off the remaining mortar with a hammer and chisel. Now we have to reinstall half bricks around the window opening. Although I am an amateur, I trust myself to do it. Still, of course, I don't want to do anything wrong and hope there are experts here who can give me tips. Oh yes, the entire joint renovation is being done by professionals; the old joints have already been removed.

1. According to the architect, the structural integrity is not affected.
2. Which mortar mix do I have to use/make?
3. Are there any other things I should consider?

Thank you in advance for your help.

Regards
- wilsumer -

If the joints are going to be worked on afterwards anyway, your question probably isn’t about a color tone problem at the old/new transition (?). There are different mortars for different stones because they differ in thirst, meaning how much water they withdraw from the mortar during its setting. For this reason, pre-wetting the stones is sometimes recommended (more for bricks than for clinker). You obviously can’t put the stones in the existing wall into a bucket of water, but you can of course treat them with a sponge. I consider small shrinkage cracks between mortar and stones unproblematic after joint treatment, and the stability concerning these half stones in the reveal is also not a cause for concern.

The keyword here is pre-wall mortar. There are also different variants for strongly and weakly absorbent stones.