ᐅ Wide joints in aerated concrete blocks

Hello,

We are currently building a new house (KfW40 standard) with exterior walls made of aerated concrete blocks (17.5cm (7 inches)) that will later be clad with brick veneer after insulation is installed. In several places where cut aerated concrete blocks meet, relatively wide joints (about 1cm (0.4 inches)) have formed, which are still open at the moment. The site manager does not see this as a problem. The gaps are planned to be filled with mortar on the outside and sealed airtight on the inside by plastering.

Is the presence of such joints already considered a defect, or is this acceptable? Will the insulation be affected by these joints? Is the planned method of sealing proper, or should it be done differently?

Thank you very much!

Hello,
there will still be an external thermal insulation composite system (ETICS) applied, right? Then it’s not a problem. Structurally, it doesn’t really matter anyway.
What else could they do, cut a brick just for one centimeter?

Best regards,

Andreas

Yes, there will be insulation made of expanded polystyrene (160mm (6.3 inches), WLG 032) applied. I do not expect 1cm (0.4 inch) thick panels. But isn’t it generally possible to cut the blocks to size?

You didn’t photograph the entire wall. Could the length of the wall be exactly X bricks plus 1 cm (0.4 inches) there?

Are there any guidelines for... insulating mortar might be an option if the width is outside the standard range (just assuming that without knowing for sure). But I wouldn’t worry about it.

No, this happened because the stones were not cut precisely. In other rows, the fit is exact. In the end, there are still only a few joints that are slightly wider.