When laying impregnated bricks the end joints will dry out by evaporation as the brick does not absorb water through the headders.
Please note!
It takes a little longer before the joints can be pressed/completed.
In generel, we recommend that you use the mortar FM 2½ from Weber for impregnated bricks. For the brick type 2.4.27 Heimdal however we recommend the mortar FM 5 also from Weber.
For load bearing walls engineers or architects can demand special type of mortar.
Read more about laying impregnated bricks in wintertimer here...